AIR SYSTEMS Flashcards
02 What is the maximum operating altitude of the CT-142?
25,000 ft ASL
02 What is the maximum crosswind component for landing?
36 kts
02 Name the 3 aircraft components
Fuselage, wings, empennage (tail)
02 What control surface handles pitch and what axis
Elevator (lateral axis)
02 What control surface handles roll and what axis
Ailerons and spoilers (longitudinal axis)
02 What control surface handles yaw and what axis
Rudder (vertical axis)
02 Define force
Energy to produce or defy motion
02 Newton’s 1st Law: Law of Inertia
A body at rest tends to remain at rest while a body in motion tends to stay in motion unless acted upon by an external force.
02 Newton’s 2nd Law: Law of Acceleration
Acceleration is directly proportional to the applied force and inversely proportional to the mass of the body F = ma
02 Newton’s 3rd Law: Law of Action and Reaction
For every action, there is an equal and opposite reaction.
02 Define static pressure
“Pressure exerted on an object by the molecular activity within a fluid.
It is measured as a force per unit area and is written: P static = force/area
EXAMPLE : at sea level, standard pressure is 14.7lbs/sq. in (the weight of a column of air above a certain area).”
02 Define dynamic pressure
A body immersed in a moving liquid will absorb the kinetic energy of that fluid (aircraft in the airstream): Pd+1/2 pv^2
02 Define Bernoulli’s Principle
An increase in dynamic pressure results in a decrease in static pressure.
02 Bernoulli’s Principle 3 requirements
Airflow is constant, air is incompressible, total pressure is equal to dynamic pressure + static pressure
02 What are the Forces acting upon an aircraft in flight?
Lift, Thrust, Weight, and Drag.
03 What type of engine gives a large mass of air a small acceleration
Turbo-Prop
03 How do propeller work?
“Pushes air backward to create thrust
Rotating blade produces lift and drag.”
03 What is the benefit of CT-142 variable blade pitch?
Engine and propeller always work at maximum efficiency
03 What is the name/type of the CT-142 engine and how many are there?
Two Pratt and Whitney 120A free-turbine, turbo-prop engines.
03 What are the specifics of the CT-142 Propeller(prop)?
Each engine drives a Hamilton Standard 13 foot diameter, four-blade, constant speed, hydraulically controlled propeller.
03 What is the shaft horse power of the CT-142?
1800 shp which can uptrim to 2000 shp in the event of an engine failure.
04 What is the certified ceiling?
25000 feet
04 What is the maximum operating speed?
242k IAS up to 14000ft, then linearly decreases to 207k IAS at 25000
04 What is the maximum landing cross winds and tail wind?
36kts, min 100ft wide | tail wind up to 10kts (20 in certain situations)
04 What is the emergency stopping distance?
1500ft on 2 engines, 1800 on 1 engine
04 What is the minimum retakeoff distance?
3000ft
04 What is the CT-142 height|length|width?
24 ft. 5 in high
77 ft. 6 in long
and has a wingspan of 85 ft.
04 What is the CT-142 base weight?
26500 lbs
04 What is the CT-142 empty tank weight (w crew and galley)?
28285 lbs
04 What is the CT-142 ramp weight?
34700 lbs
04 What is the CT-142 take off weight?
34500 lbs
04 What is the CT-142 max landing weight?
33900 lbs
04 What is the CT-142 max fuel with 8 crew?
6415 lbs
04 How many exits does the CT-142 have and where are they located?
4 Airstair door, mid-cabin emergency exit, forward cabin emergency exit, flight compartment hatch. Note the cargo door is not an emergency exit and can’t be opened from inside.
04 How is the main door pressurized?
It is charged from the pneumatic de-icing system and contains a reservoir sufficient to seal the door 4 times after engine shutdown. You must ensure the aircraft is de-pressurized before completely unlatching. And NEVER stand directly under the door when unlatching.
04 What kind of breaks does it have?
Main gear has disc brakes, anti-skid brake system and emergency/parking brake system
04 In case of loss of hydrolics, how is the landing gear dropped?
Gravity dropped, then hand-pumped in locked position.
04 How many fuel pumps does it have?
6, 3 per side.
04 What is the purpose of the surge bays in each wing tip?
They provide positive tank venting
04 What is the prefered fuel?
F-37 (JP8+100) | Freezes at -47
04 How many hydrolic systems?
3 separate hydraulic systems
No.1 engine driven
No.2 engine driven
Emergency hand driven system (hand operated from the cockpit and provides power for emergency landing gear extension)
04 What is bleed air used for?
“Air is bled off the compressors of the engines, for use in:
Air Conditioning
Pressurization
Pneumatic De-icing
Bleed air is also available from the APU”
04 Where is the AC control panel located?
Control panel is located on the overhead panel in the cockpit.
04 What is the aircraft pressurized to?
25 000ft
04 What compartments get pressure sealed?
“Once engines are running, bleed air is selected on, and flight compartment, cabin, cargo compartment, and underfloor are sealed.
“
04 Which part of the aircraft uses bleed air for de-icing?
“Bleed air is used to de-ice the leading edges of the:
wings
nacelle intakes
horizontal stabilizer
vertical stabilizer
“
05 As a student, when should you reset cct breakers?
As a student, never reset a CB, inform instructor or pilot.
05 Which wing has a green nav light?
The right wing. (Port wine is red, red i on the left/port side.)
05 What type of lights are used for landing/approach?
White, 600 Watt quartz-halogen sealed beam lights
05 What and where are the interior lighting?
*Airstair Door: And a light to illuminate the entrance
*Baggage Compartment: There are lights in the baggage compartment which come on with the switch, or when the baggage door is unlocked.
*Cabin Aisle: Four incandescent lights to illuminate the cabin aisle.
“*Cabin Overhead: There are five panels of fluorescent lights to illuminate the cabin
*Crew Rest Area: Two incandescent lights to illuminate the crew rest area.
*Galley Counter: There is an incandescent light over the galley counter.
*Galley Overhead: And one over the galley area.
*Lavatory Incandescent: The switch for the lavatory lights illuminates the incandescent light, and arms the fluorescent light.
*Lavatory Fluorescent: This light comes on when the door is locked.
*Wardrobe Overhead: Another light overhead the wardrobe area.
*Workstations: There is an array of lighting available at the individual workstations which you will see on your static visit.
05 What powers electric anti-icing and de-icing?
115Vac variable
05 What can be anti or de-iced?
“Prop Blades *
Pitot Tubes
Static Ports
Stall warning transducers
Engine intakes
Windshields
Pilot’s side window
Elevator horns
*NOTE: Because these can be turned on at the pilot’s discretion, they are considered in the AODs as part of the De-Icing System as well.”
05 What does static air provide information to?
“Air Speed Indicator (ASI)
Vertical Speed Indicator (VSI)
Air Data Computer
Standby Barometric Altimeter”
05 What does pitot air provide information to?
“Air Speed Indicator (ASI)
DADC”
05 Where are the Stall Warning Transducers and what do they do?
“Located on the leading edge of each wing
Measures the angle of attack”
06 What is a RADAR?
an electronic device used for the detection and location of objects
06 What does RADAR stand for?
RADIO DETECTION AND RANGING
06 What are the uses of RADAR?
Map Reading & navigation
Weather Detection and Avoidance
Traffic Detection and Avoidance
Altitude (Radalt)
Groundspeed and Drift (Doppler)
Guidance Systems (homing RADAR on missiles)
Target Detection and Homing
06 describe range determination
Short, strong bursts of radio energy (pulses).
Energy is reflected back to the receiver (echo).
Time it takes the energy to return can be converted to distance.
06 Name and define factors affecting determination
Range – due to spreading, return signal may be too weak to be detected by receiving antenna
Size – large targets more likely to be detected, small targets may be filtered out, depending on RADAR
Shape – right angled objects more conducive to reflecting signal back to receiver
Reflecting characteristics – some compounds reflect more readily than others, entire branch of military research is dedicated to researching and developing military assets that generate the least possible RADAR return.
06 What is the ideal RADAR pulse
one that reaches peak power very quickly (sharp leading edge), maintains that power throughout the pulse (flat top) and ends abruptly (sharp trailing edge).
06 A pulse that drops power gradually at the end of the pulse is said to have a _______, while one that builds slowly to peak power is said to have a _______
sloped trailing edge, sloped leading edge
06 Sloping edges effectively ______ the width of the pulse and can also cause timing ambiguities.
increase
06 Pulses which have varying power throughout the duration of the pulse are said to have ________. Sloped pulses are inefficient in that peak power is only achieved for a short portion of the pulse
Sloped tops
06 The shape required for range accuracy
To achieve the accuracy the set was designed for, the pulse must have a sharp leading edge. This allows an accurate start of the timing to measure the pulse, and thus, the target’s distance
02 what are the 2 basic ways to increase lift
Increase airspeed
Increase the camber of the aerofoil
02 What is the camber
the curvature of an aerofoil or its surface
03 Define thrust
Fuel is fed into some kind of “engine” where, in burning, its’ chemical energy is changed into thermal energy which is converted into the mechanical work done in propelling the aircraft against the drag.
03 What is coarse pitch setting used for?
cruise
03 Which type of engine gives a large mass of air a small acceleration?
Turbo-prop
03 Name four common types of engines
Ram-Jet.
Turbo-Jet.
Turbo-Fan.
Engine/Propeller Combination.
03 What is a free turbine
In the free-turbine system, the propeller is connected to what is referred to as a power turbine which “floats” in the high pressure exhaust gases in the turbine section.
03 Disadvantages of propellers
Difficult to make propellers work well at high speeds, because of:
Rotational speeds
Supersonic flow at the blade tips
03 types of pitch
Coarse Pitch
Fine Pitch
03 define pitch
Distance in feet a propeller travels forward in one revolution.
Angle at which the blade is set governs the pitch
03 define course pitch
Blade set at a large angle, therefore the blade will travel a greater distance forward per revolution
Best suited for high speed cruise
develops high cruising speeds at low engine RPM
gives good cruise performance and fuel economy
03 define fine pitch
Propeller will revolve at higher speed around its own axis, thereby enabling the engine to develop greater power
Best performance during takeoff and landing
good take-off and climb performance
inefficient both in speed and fuel economy in cruise
03 Mechanisms for Varying Pitch
Mechanical
Hydraulic
Electrical
03 function of a propeller
To convert the rotational force (Torque) produced by the engine into a forward push or pull, called thrust, for forward speed.
03 operation of a propeller
Designed to move forward in a corkscrew motion.
Pushes air backward to create thrust in the opposite direction.
Propeller blade cross-section is similar to an airfoil or wing.
As it rotates, it produces lift and drag.
Forces are designated as thrust and torque
03 Turbo-Prop gives a large mass of air a ______ acceleration
Turbo-Jet/Fan gives a small mass of air a ______ acceleration
small, large
03 Indicated Horsepower =
= PLAN/33000
P = Mean Pressure in lbs. per square inch (psi)
L = Length of the stroke in feet
A = Area of the piston in square inches
N = Number of power strokes per minute
33000 = 1 Horsepower = amount of work to raise 33000 lbs. 1 foot in 1 minute
AS 07 What are reception factors for radar?
*Target range, size, shape and reflecting characteristics.
*Pulse shape, width and repetition frequency.
*Radar power output and receiver sensitivity.
AS 07 How can you overcome sea return interference?
reduce altitude,
reduce GAIN. If the dash 8 radar is operated in Linear (degraded) mode, then gain must be manually manipulated.
raise antenna tilt, and
select sea mode; the Dash‑8 has an automatic sea switch that optimizes return for sea surface.
AS 07 What are the reception factors for sea vessels?
Ships and boats on the water will look similar to small islands on the radar. Careful use of the topo is required to avoid confusion.
Strength of return will vary depending on the composition of the vessel (metal or concrete hull will provide much stronger returns than wooden boats).
Sea state will have strong influence on the range at which targets can be detected.
AS 07 How do rivers show up on radar?
Rivers, if they are wide, will show up dark. The far shore of a river or lake will appear much brighter than the near shore. Narrow rivers may be identified solely by the bright return from the far bank.
During the winter, ice may cause clutter on the returns from lakes and rivers but the outlines should be easily identifiable.
AS 07 How do hills and mountains show up on radar?
Mountains block off the radar echoes and cause a mountain shadow. The shape of this area will change as the aircraft moves past the mountain. The near edge will appear brighter than far edge.
AS 07 What are the reception factors for urban centres?
*Buildings are very good reflectors due to their shape and the materials they are made of.
*Towns often lined up N-S/E-W creating cardinal effect.
04 What is the CT-142 Galley Equipment & Pubs weight
65 lbs
AS 07 What variables affect the strength of returns?
*target size and shape
*target composition
AS 07 What environmental elements show from strongest to weakest?
Metal, concrete, rock, wood, earth, water, ice
04 What is the CT-142 crew weight
1720 lbs
AS 07 How may the shape and size of an object be distorted?
POWER and PRF
SPOT SIZE (the resolution of your display)
PULSE WIDTH (1 microsecond = 328 yds) (Range Resolution)
BEAM WIDTH (Azimuth Resolution)
COMBINED ERRORS
AS 07 What are two ways to get range on a radar?
1.Check Range Selection
count markers and multiply marker value
measure to leading edge of target
be aware of slant range less than 10 nm at 24,000’ will result in 1 nm or greater error (we want ground range)
2.The TMT cursor will provide range to target in nm, it is controlled by the trackball and is displayed at the bottom left of the RADAR display
04 What is the CT-142 max empty tank weight
31000 lbs.
AS 07 Describe the interaction between radar and precipitation?
*The radar “sees” water droplets.
*The intensity of the radar return depends on the size of the droplets and their concentration.
*The larger the droplet and the greater the concentration, the more intense the return.
*Close relationship between turbulence and rain gradient (rain shear).
*The greater the change in water content, the more severe the turbulence.
AS 07 Describe the relationship between radar and thunderstorms?
*Beginning of mature stage of thunderstorm when turbulence greatest.
*Strong updrafts and downdrafts with rapid changes in wind direction occur.
*Depicted on radar scope as sharp edged echo rather than fuzzy one.
AS 07 What are two features of hail that make it difficult to detect?
*While ice may be a good material for reflection, the shape of hail, density, intensity may give varying levels of returns.
04 What is the CT-142 Main tanks capacity
5678 lbs
AS 07 What are radar returns associated with hazardous weather?
*Edges of the weather return resembling pointed fingers, or hooks may indicate hail, or even tornadoes.
*Scalloped edges or rapidly changing edges indicate a developing storm and should be avoided by greater distances.
AS 07 What is the weather avoidance rule?
*5 nm when flying below the freezing level,
*10 nm when flying above the freezing level, and
*20 nm if flying above 30,000 ft.
AS 07 What weather options does the AN/APS-504 have?
Weather (WX) or weather contour (CTR)
04 What is the CT-142 auxiliary tanks capacity
4566 lbs
AS 07 What does the Weather (WX) option do?
*orients display to line of sight (LOS) and sector offset
*provides signal processing to show areas of strongest returns within a cell
04 What is the CT-142 Total usable fuel
10244 lbs
04 What is the CT-142 max fuel with 8 crew
6415 lbs.
AS 07 What does the Weather Contour (CTR) option do?
*Suppresses areas of high precipitation in the display to give a brightly outlined weather display
AS 07 How can you register weather phenomena better with the radar?
*For best results, the antenna tilt should be adjusted to a point just above the reception of ground clutter to avoid confusing ground and weather returns.
*Radar range should also be adjusted frequently between short to longer ranges to avoid flying into a blind alley.
04 describe No.1 engine driven hydraulic system
1 System (WAIRM)
Wing Flaps
Anti-skid control valve
Inboard roll spoilers
Rudder actuator (lower)
Main Wheel Brakes
04 describe No.2 engine driven hydraulic system
2 System (LONER)
Landing gear
Outboard roll spoilers
Nose wheel steering
Emergency/Park brake
Rudder actuator (upper)
04 The #1 and #2 hydraulic systems are engine driven. Each system is backed up by an _________. All systems use a synthetic phosphate ester-based fluid (SKYDROL)
electrically driven standby pump
05 The CT-142 requires a _______ Ground power cart
28V DC 1500 AMP
05 Where is the battery compartment located
left side of the nose of the aircraft
05 Why 24V Batteries when the A/c works on 28V DC??
You always want the battery to be less than the system it is connected to because the output voltage of your generators will fluctuate, and you don’t want the batteries being used unless it is necessary. E.g.. Resort to batteries only if the normal system has failed, not when it is fluctuating normally because of system load….which could be, for example, between 25-29.5 Volts for a 28 V system
05 Define generator
generates electrical current through the movement (generally spinning) of either wires through a magnetic field or a magnet near a fixed coil of wires.
05 define motor/starter
the opposite of a generator. Uses current to generate a magnetic field which spins a magnet.
05 define dc
direct current; current that is always moving in the same direction along the wire. (can be fluctuating)
05 define ac
alternating current ; current that changes direction along the wire. (must be fluctuating)
05 define voltage
electrical pressure. A measure of the pressure under which electricity flows.
05 define transformer
either steps-up (increases) or steps-down (decreases) a given voltage (does not change frequency of AC and cannot change AC to DC or vice versa)
05 define inverter
converts DC into AC
05 define rectifier
converts AC into DC
05 where is the APU (auxiliary power unit) located
Located behind the rear pressure bulkhead in the fuselage of the aircraft.
05 How many inverters are there on the CT142 and what are they
3 for avionics
3 for the search radar
3 NTS inverters
05 DC power sources
DC – can use the acronym BETS
Batteries x 2 24 Volt DC
External DC 28 Volt DC cart
TRUs x 2 converts 115 Volt AC to 28 Volt DC
Starter/Generators x 2 28 Volt DC
05 ac power sources
AC – can use the acronym GEIA
Generators x 2 115 Volt AC
External AC 115 Volt AC cart
Inverters x 9 converts 28 Volt DC to 115 Volt AC
APU x 1 115 Volt AC
05 what is a Bus Bar Protection Unit (BBPU)
a box, tying or breaking of circuits if a loss is detected or a short circuit occurs. This prevents damage to the electrical system.
05 when is a one time reset for a tripped CB acceptable?
The AC is on the ground
There is no recent history of reported defects with the system or related systems or other evidence of anomalies.
There is no other evidence of anomalies with the affected systems; and
If a circuit breaker is reset, a record of this action must be made.
05 where is the pilot and copilot pitot head located?
The pilot pitot head is located on the port side of the fuselage and supplies the pilot airspeed indicator and the No. 1 DADC
The co-pilot pitot head is located on the starboard side of the fuselage and supplies the co-pilot airspeed indicator and the No. 2 DADC
05 what and where are the static heads located?
The static heads are located forward and above the pitot heads flush on each side of the nose.
Unlike the pitot heads which measure the pressure of the moving air, static ports measure the “still” air pressure (hence their name
AS 08 What are the parts of the antenna?
*14x42-inch flat plate planar array.
*360 degrees rotation capability.
*Pitch, roll and hdg from IRU are sent to the Antenna to ensure the Antenna rotational plane remains stationary with changes of AC attitude, up to 20° from horizontal.
*Manual Tilt control +/-16°.
AS 08 What are the parts of the waveguide pressurization system?
The RF energy from the receiver/transmitter is sent to the antenna through a waveguide flange to a waveguide rotary joint in the pedestal and is sent through rigid and flexible plumbing for radiation.
Located in the nose (through upper left nose equipment panel).
Pressurizes the waveguide and R/T with nitrogen to prevent condensation and arcing at high altitude.*
AS 08 What are the parts of the radar power supply?
There are three separate inverters located in the aircraft’s nose which provide power for the radar only.
These are accessible from the access panel on the Starboard side of the aircraft.
The radar power switch is located on the co‑pilot’s side console.
The radar inverter power switch allows the three radar inverters to power up and supply radar system with 115 V AC
Allows inverter DC source from either L Main or R Sec DC bus
Besides the three circuit-breakers in the cockpit, there are two 90 amp CB’s on the DC contactor panel in the radome.
These supply the DC power required by the Radar inverters (only one or other is used dependent on position of inverter switch)
AS 08 What are the parts of the radar receiver/transmitter?
The transmitter generates a RF signal and the receiver processes the returned RF signals for conversion to a video signal. The R/T isolates and monitors faults and key radar parameters.
The transmitter frequency is 9310 to 9375 MHz. It has an 80 KW minimum peak signal and 100 KW is typical. The receiver rejects USB. The R/T is located in nose.
The waveguide is the conduit that transports the EM wave from the amplifier to the antenna. Due to the high power output of the amplifier (100 Kilo Watts!), the waveguide needs to be pressurized to prevent arcing.
AS 08 Where are the main RADAR components?
*Power Supply – NTSC power supply (DC pwr)
*Navigation Training System Computer (NTSC)
*Remote Radar Interface Unit (RRIU)
*Synchronizer Processor Converter Unit (SPCU)
AS 08 What is the NTSC?
- The NTSC is the heart of the NTS. It interfaces with the radar via RRIU and it processes all video data.
AS 08 What is the RRIU?
*The Remote Radar Interface Unit (RRIU) interfaces the ATS computer with the search radar via a full duplex RS-422 data link. This interface allows the radar to be controlled by operator inputs through an emulated CDU.
The RRIU also interfaces the radar with the PCU, allowing pilot-control of the radar when the NTS is not selected
AS 08 What is the SPCU?
*Synchronizer Processor Converter Unit (SPCU):
*Provide overall radar system timing and control, video/signal processing and radar scan conversion.
*Supplies the transmitter with command and control signals.
*Receives radar video inputs from the receiver.
*Contains control/sync circuitry, video signal processing circuitry, and scan converter circuitry.
AS 08 What ranges are available on the Radar?
The 3, 6, 12, 25 mile ranges are narrow pulse, high pulse repetition frequency (PRF) for good target definition and range resolution; 100 and 200 nm are wide pulse, low PRF for long range detection.
AS 08 Which 50 nm positions for optimum operation are available?
50nm narrow pulse, high PRF is for target definition and good target detection at close range by providing more target returns per scan.
50nm wide pulse, low PRF keeps the average power high, provides the time needed to receive returns at longer ranges improving long range target detection capabilities.
AS 08 What are the range to RPM relationships?
3 nm to 50 nm NP = 30 RPM
50 nm WP to 100 nm = 12 RPM
200 nm = 7.5 RPM
AS 08 Explain Fault Response - Radar Hot?
This is an indication that the radar SPCU is overheating. The radar system has to be switched off via the radar power switch located on the co-pilot’s side panel to prevent any further damage to the radar system.
Open the computer cabinet and inspect for smoke or fire.
06 fill in the blanks
06 Narrow pulse = worse or better range resolution?
better
06 Wider pulse = greater/lesser total pulse energy = greater/lesser maximum range
greater,greater
06 what does the synchronizer do
Provides timing for the entire system.
Generates Pulse Repetition Frequency (PRF) and display range markers.
Triggers the modulator to release energy.
May be a separate unit by itself or it may be included in the transmitter.
06 what does the modulator do
Stores energy between pulses.
Determines the waveform of the output pulse (shape).
Releases pulses of energy when directed by the synchronizer.
06 what does the transmitter do
Provides RF energy at an extremely high power in very short pulses.
Carrier frequency must be extremely high to get many cycles into the short pulse.
Power is carried to the antenna by coaxial cable or a waveguide.
06 what does the antenna do
Highly directional, usually rotated or moved back and forth between two positions.
Normally a rotating planar array which transmits and receives RF energy.
Switching device (duplexer) is used to alternate between transmitting and receiving.
06 what does the receiver do
Very sensitive super-heterodyne receiver.
Superheterodyne receivers reduce the signal frequency by mixing in a signal from a local oscillator to produce the intermediate frequency (IF).
This allows better signal isolation (less noise and spurious returns/info)
Accepts signals from 1 to 10 MHz.
Detects and amplifies weak RF echoes.
Changes echoes to video and sends a signal to the indicator.
06 what does the indicator do
Visually presents all necessary information to locate the target on the screen.
Method of presenting the data, often referred to as a type of scan, depends on the RADAR’s purpose.
06 what are some common indicator presentations
‘A’ Scan
‘B’ Scan
‘C’ Scan
‘J’ Scan
‘E’ Scan
Plan Position Indicator (PPI) Scan
06 describe the A scan
Mainly used to determine range but rough direction can be obtained by rotating antenna until maximum echo is received is obtained.
The pulse travels from left to right across the indicator and Vertical deflections from transmitter pulse represent target returns.
06 describe the b scan
Used to determine range and bearing as well as determine target size.
The bearing and range of reflective objects are presented as abscissa and ordinate, respectively.
06 describe the c scan
The echo appears as a bright spot with the azimuth angles as the horizontal coordinates and the elevation angle as the vertical coordinates.
Has been used by night fighters to help follow enemy aircraft.
06 describe the j scan
Modification of the A Scan, in which the spot rotates in a circle near the edge of the CRT face. An echo appears as a deflection from the circle.
As the distance changes, the deflection moves around the circle like the pointer of the aneroid altimeter.
Normally used for radar altimeter
06 describe the e scan
Modification of the B Scan, echo appears as a bright spot with the range as the horizontal coordinates and elevation as vertical.
Normally used for precision approach radar (PAR), where A/C must follow a certain angular line to reach the touch-down point on the left of the screen.
06 describe the PPI scan
Provides range and bearing info
Most common for navigation radar
Provides a map like picture
06 how does the PPI scan work
The antenna generally is rotated uniformly about the vertical axis so that the searching is accomplished in a horizontal plane.
The beam is usually narrow in azimuth and broad in elevation, and large numbers of pulses are transmitted for each rotation of the antenna.
When an echo is received, the intensity of the spot is increased, and a bright spot remains at that point on the screen even after the scanning spot has passed. Thus it is possible to produce a map.
09 How many portable fire kits are there on the CT-142
3
09 How many and where are the hard wired O2 systems
2; one in the cockpit and one in the aft cabin
09 What are the three O2 systems on the Dash-8?
Pilot system
Nav trainer system
Fire Fighting Portable system
09 What are the components of the computer rack
Rack CBs, NTS server, NTS power supply, RRIU, SPCU, Nav Interface Module (NIM)
09 How many/where are the Fire Fighting Portable Oxygen Systems
3 crew O2 bottles, #1 is located behind the copilot on the floor. The second is stored in the emergency equipment stowage compartment by the airstair door. The third system is located next to the baggage compartment door on the front of the aft bulkhead
09 What is the max pressure/min dispatch for the NTS O2 system?
Max pressure 1800 psi (1248 L)
6 crew: 60 min/person O2 diluted setting
10 min/person O2 100% setting
Min dispatch 1300 psi
6 crew: 41 min/person O2 diluted setting
7 min/person O2 100% setting
09 Each console oxygen system consists of:
a pressure demand regulator
quick don oxygen mask
smoke goggles
09 If at minimum dispatch, time is reduced accordingly to _____ min at the diluted setting and _____ min if demand is at 100%.
41, 7
09 What is the max pressure/min dispatch for the Fire Fighting Portable O2 system?
Max pressure 1800 PSI. Min 1800 PSI !!
Demand or pressure breathing at 55psi at mask
Approximately 15 min (310 L) O2 @ 100%
09 What is the max pressure/min dispatch for the pilot O2 system?
-Max dispatch 1800 psi (987 litres)
2 crew: 140 min/person O2 diluted setting
25 min/person O2 100% setting
3 crew: 90 min/person O2 diluted setting
16 min/person O2 100% setting
-Min dispatch 1300 psi (2 crew) 1800 psi (3 crew)
2 crew: 98 min/person O2 diluted setting
17 min/person O2 100% setting
09
10 How do you know which console has tuning control of the HF Radio?
Green Bar is illuminated at the HF control switch.
10 What is squelch and where do we set the squelch when using the HF radio on the Dash-8?
Reduces background noise / full clockwise.
10 How do you get rid of an error message (E) in the display window?
Press the STO button.
10 Do the VHF radios on board the CT-142 use AM or FM? What is the frequency range?
AM.
118.00 to 151.975 MHz
10 How many comms Receiver/Transmitters are there on the CT-142?
4
2x VHF, 1x UHF, 1xHF
10 What is the practical UHF frequency range for the CT-142?
225.000-399.975 MHz, divided into 25 KHz steps.
10 The Audio Integration Systems at each student console consists of:
Audio Control Panel
Headset with PTT (press to talk) switch
PTT switch mount on the footrest
10 The Audio Control Panel provides aircrew with the means to:
Control transmission and reception on external radios.
Communicate internally on different interphone conferences (ICS - INT, PRI 1, PRI 2).
Monitor the aircraft navigation receivers (VOR/ADF).
Access the passenger address (PA).
10 What are the 3 interphone conferences available:
PRI1 , PRI2, and INT
INT is available to all positions
PRI1 is only available to the pilots, flight engineer, I1, I2, and rest areas.
There are two PRI2 conferences allowing each instructor to communicate with their students. Crew at the rest area can select which PRI2 to listen to.
10 CT-142 HF Radio System consists of:
King KHF 950 HF radio
Radio control panels
—–Located at each student consoles, instructor consoles, and centre console of the flight compartment.
Transceiver (Transmitter/Receiver)
—–Located in the avionics rack
Antenna
—–Located in the leading edge of the vertical stabilizer
10 What is the CT-142 HF Radio Frequency Coverage:
Frequency Coverage: 2.0 – 29.999 MHz
10 Tuning steps for HF radio
Take control of HF radio
Adjust volume and squelch
Set desired frequency – push freq selector knob
Rotate freq selector knob until desired digit displayed
Push freq selector knob again to switch to next number you wish to change
Once desired freq is displayed, select HF on ICS panel, key mic once and wait until “TX” stops flashing (approx 5 sec)
Once flashing stops, transmit message
10 If unable to tune radio, try the following troubleshooting procedures:
Change the volume setting, put it back to mid range and try again.
Recycle Power (Off/On)
Have another station take control of the HF, then take control back.
Have pilots take control of the HF, then take it back after 1-2 min.
10 What is SELCAL
SELECTIVE CALLING
When the ground station transmits this code, a light on the SELCAL control panel (located on the centre console) will flash and the crew will get a tone in their headset.
This enables you to monitor an HF radio without having to listen to static, or chatter that does not concern your aircraft (e.g. trans-oceanic flights).
10 VHF King KTR-908 Radio components
Two CDUs, one per radio (VHF1/2), located in the centre console of the flight deck
Transceivers for both are located in the avionics rack (in the wardrobe)
Antenna
Pilots can tune 2 frequencies, one active, one standby
10 What are the VHF King KTR-908 Radio Specifications:
Amplitude modulation (AM)
Frequency range: 118.000 to 151.975 MHz
Spacing of channels: 25 kHz
Line of sight operation (LOS)
Low power (not more than 26 watts)
Quiet, static free communication
Not affected by weather
Memory for 9 preset channels
Capable of Direction Finding (DF) – Ref AOD Sec 21.1.9
10 What are the UHF AN/ARC-164 Radio Specifications:
(AM) Amplitude Modulation
Frequency range - 225.000 to 399.975 MHz (in 25 KHz steps)
Memory for 20 preset channels
28 volt DC
Line of sight (LOS) operation
Quiet, static free communication
Not affected by weather
Capable of Direction Finding (DF) – Ref AOD Sec 21.1.9
10 What are the UHF AN/ARC-164 Radio Components:
2 Transceivers – located in cockpit on the centre pedestal, aft of the power levers.
1 main transceiver (for transmission and reception), and 1 Guard receiver (for reception only on 243.000 MHz).
1 Control Head – co-located with transceivers on centre pedestal.
Antenna
11 What is an Inertial Navigation System?
A navigation aid that uses a computer and motion sensors (accelerometers) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references.
11 What are the four basic components of an INS?
Accelerometers
Computers
Stable platform
Control and Display Unit
11 What is an accelerometer?
A basic device for measuring acceleration
11 How does the Ring Laser Gyro operate? (Stage 1 of 3)
Light is used to measure angular rates of motion.
A physical interference is created within a RLG using 2 lasers in a common cavity
The lasers are fired simultaneously and travel in opposite directions around the cavity but on separate paths (i.e. no interference between beams).
11 How does the Ring Laser Gyro operate? (Stage 2 of 3)
If the RLG is stationary, then the beams should complete the trip around the block in the same time since the optical path for both lasers is the same.
The phase relationship between the two beams at the detector (i.e. after beam travel) will be identical to that emitted initially.
11 How does the Ring Laser Gyro operate? (Stage 3 of 3)
The detector will observe an identical interference pattern to that emitted.
If, however, there exists angular or azimuthal displacement (rotation) the optical path lengths will be unequal.
This simply implies a time difference between the beams for the trip, which can be measured by phase difference and a changing interference pattern.
11 What does the Cervit block of the RLG consist of?
-3 or 4 mirrors
-Anodes and cathodes
-a prism
-photocell detectors
-dither motor
-optical paths for laser beams
-inert gas
11 Explain differential path length?
One error which degrades the performance of the RLG is differential path length:
Temperature differences between CERVIT cavities of even a fraction of a degree Celsius creates a time/phase difference.
Eliminated by using one CERVIT Cavity for both lasers.
11 Explain lock in?
A second error that can degrade the RLG is lock in:
Non perfect optics within the cavity and mirrors will cause a certain amount of back-scattering.
Back-scattered energy will tend to reinforce the beam energy traveling in opposite direction.
At low rates of rotation, frequencies are combined, producing a dead zone.
This would lead to drift rates of 40 to 50 degrees per hour if left undetected.
11 How can you eliminate lock in?
Via Mechanical Bias (dithering)
-Vibration of the RLG
-Any error created by the dithering motion is averaged out and eliminated
-dithering will cause two extremes every cycle but the average (right down the middle from both extremes) is the end result while preventing lock in
11 What are the two main advantages to INS integration?
-Much improved accuracy.
-Higher mission completion rate as sensors may be used independently.
11 What are the two main disadvantages to INS integration?
-Loss of complete self-containment
-Loss of covertness, dependence on external radiation
11 What are the four ways to integrate INS?
-Ground referenced hybrid system
-GPS-INS hybrid
-Doppler-INS hybrid
-Celestial-INS hybrid
11 What are the desired characteristics of an accelerometer?
Low threshold of sensitivity.
Wide range of sensitivity.
Linear output.
High resolution.
11 Explain levelling?
In the local level system this means bringing the X and Y accelerometers to a condition where no component of gravity is sensed
11 What is the reference for azimuth alignment?
True North.
11 What 10 coordinates are required for levelling and alignment?
-2 initial position coordinates -LAT/LONG
-2 initial velocities - N & E
-3 initial orientations - X,Y, and Z gyros
-3 orientation rates
11 Name 4 types of INS alignment?
-Self Alignment (most popular method
-Reference alignment (involving external data source)
-Moving alignment (carrier-based aircraft)
-In-Flight alignment (ability to align airborne)
11 What are the 5 steps of self alignment?
-Warm-up – no moving parts for strapdown system, alignment performed by the computer based on inputs from accelerometers and RLGs
-Coarse Levelling – accelerometer readings determine initial aircraft attitude
-Coarse (azimuth) Alignment
-Fine Levelling
-Fine Alignment AKA Gyro Compassing
11 What are the two High Latitude Alignment problems?
-Inability to accurately resolve True North (issue at latitudes above 70 degrees)
-undetectable tilt (prevents initiation of gyro compassing)
11 What are the differences between a bounded error and an unbounded error?
-Unbounded errors increase with time.
-Bounded errors oscillate about a mean value with time.
Bounded errors dominate first, then unbounded errors introduce the greatest errors.
11 What are three sources of bounded errors?
-Initial levelling (platform tilt-computer error)
-Accelerometers (acceleration errors)
-First integrator errors (velocity errors)
11 How long does the Schuler Period last?
84.4 minutes.
11 What are three sources of unbounded errors?
-Levelling gyro drift
(produces the largest single error source within an INS)
-Initial azimuth misalignment
(operator input)
-Azimuth gyro drift
(Second largest source of total error)
12 What are the two essential components of the IRS?
-Inertial Reference Unit (IRU)
-Mode Selector Unit (MSU)
12 Describe the IRU?
-The IRU contains an inertial sensor assembly, microprocessors, power supplies, and aircraft electronic interfaces.
-Located under the centre floor of the crew compartment.
-Housed on a rack that also serves as the electrical and mechanical interface between the IRU and the aircraft.
12 Describe the MSU?
-The MSU provides inertial mode selection, status indication, and remote test initiation.
-Located in the flight deck centre console.
12 What are the principles of operation for the IRS?
-The Honeywell IRS is a strap-down, Schuler-tuned inertial reference system that senses movement and attitude through the output of inertial sensors.
-Accelerometers and ring laser gyros in the inertial sensor assembly measure accelerations and angular rates of the aircraft.
-The microprocessors perform the computations required to provide parameters for the flight control and display instruments.
12 What are the electrical requirements for the IRU?
The IRU receives AC and DC power from the aircraft, and provides switching to primary AC or secondary DC.
12 What are the cooling requirements for the IRU?
-The IRU requires a cooling air supply. Cool air is supplied via the aircraft air conditioning system or the AC/DC blower kits.
-A loss of cool air will necessitate shutting off the IRU after a specified time.
12 What are the four basic inertial modes for the IRU?
-Off
-Nav
-Align
-Attitude
12 Describe Align Mode?
-The IRU aligns its reference axes to the local vertical and computes heading and latitude by measuring horizontal earth rate components.
-Completes alignment in a minimum of 2.5 minutes at the equator and a maximum of 10 minutes at 60° to 70° latitude.
-At latitudes above 70° additional alignment time may be required.
12 Describe Nav Mode?
-In the Nav mode, the IRU supplies inertial position reference for the aircraft and provides outputs via the FMS:
Aircraft attitude
Body rates
Body accelerations
True heading
Velocity vectors
Wind data (requires TAS from DADC)
Latitude and Longitude
Inertial altitude
-The IRS uses the latitude and longitude entered during the Align mode as the starting point for positional computations
12 Describe Attitude Mode?
-Once rapid levelling has been completed provides valid outputs of :
body axis accelerations,
attitude rates and angles,
vertical velocity, and
inertial attitude.
-No navigation outputs are provided!
-Should be selected in the air under two conditions:
When the MSU fault enunciator illuminates, (indicates critical fault & all outputs invalid)
After the IRS has temporarily lost all power
12 What are the alignment requirements?
-Operator must enter present position via the FMS.
-IRU conducts a reasonability test of new position: compares with previous position at last shutdown.
-If new position > 1° of the stored value, test is failed.
-A correct position may fail test if:
new IRU has been installed,
aircraft has been moved since last shutdown.
-Entering identical co-ordinates twice will override the test.
12 Describe the system performance test?
-Entered latitude must pass system performance test at end of alignment phase.
-Latitude entered must be within 30 min of arc of the latitude computed by the IRU during alignment.
-If the entered latitude passes the system performance test, alignment is complete and it allows entry into the Nav mode.
12 Describe IRU interaction with the ATS?
Information is fed from the IRU directly to the ATS. The ATS maintains a data base of inertial information, including:
True heading
True track angle (TMG)
Present latitude and longitude
Inertial groundspeed
Wind velocity (speed and direction)
System status
12 How does the IRU operate?
-Standard aircraft IRU operation
-IRU data to pilots through FMS
-IRU data to Navs through ATS via FMS
-Data presented and manipulated in an “Emulated INS”
12 What does the Warning light indicate on the Emulated INS control panel?
Light indicates a system malfunction that prevents alignment or when an incorrect latitude (>0.5 degrees) has been inserted by the operator
12 What are the three modes available on the emulated INS control panel?
-Manual
-Auto
-Remote
12 What does the alert annunciator indicate?
Light flashes yellow when the aircraft is 90 seconds from waypoint capture and stops flashing upon waypoint capture.
12 What does the Battery light indicate?
If this was a real INS, this light would indicate that there is an INS power supply problem. The ATS INS is emulated, so this is not functional.
12 What are the two main categories of information provided?
Navigation and Attitude.
12 What is the source of the inertial information used by the ATS?
The aircraft IRU.
13 What is an ADF?
An abbreviation for Automatic Direction Finding, which is a system in the aircraft.
13 What are the components of an ADF system?
An ADF receiver, antennae and a bearing indicator (RMI = Remote Magnetic Indicator).
13 What are the NAVAIDS used on the ground with the ADF system called?
Non-Directional Beacons (NDBs)
13 What are the principles of operation of an ADF? (1 of 3)
-Low/medium frequency radio receiver with directional and fixed antennas.
-Receive signals from navigation beacons and commercial radio stations.
-Indicates continuous COMPASS bearings to a transmitter which are indicated on a RMI.
13 What are the principles of operation of an ADF? (2 of 3)
-Readings must be corrected for aircraft variation and deviation to give TRUE bearings.
-In order to use an ADF true bearing, a protractor must be aligned to the local North of the aircraft.
-Subject to interference from atmospheric noise and thunderstorms due to the frequency band.
13 What are the principles of operation of an ADF? (3 of 3)
-The ground wave may be contaminated by sky-waves.
-Aircraft electrical fields and structure can also cause interference.
-Accuracy: ± 3° is the 402 Sqn accepted standard error (± 30° under poor conditions).
-Range: up to 200nm (200kHz) - 50nm (1600kHz) decreases at night (sky-wave contamination).
13 What are the components of the King KDG 806 ADF?
-Radio compass receiver - avionics rack
-Control display unit:
#1 pilot side, center avionics pedestal
#2 co-pilot side, center avionics pedestal
-Antenna assembly - underside of fuselage just forward of main gear
-Bearing indicators:
pilot, co-pilot, ACSO consoles
13 What are the operating frequency limits of the King KDG 806 ADF?
190.0 - 1799.0 kHz.
13 Explain how the KDG 806 ADF receives audio?
-The ADF needle indicates the relative bearing of the transmitter. The RMI compass rose enables indication of compass bearing to the station.
-Receiver audio is sent to the audio integration system.
-Absent or muted audio indicates that the selected frequency is too weak for dependable navigation, or that FMS is in Aux Mode.
13 Explain the characteristics of the VOR?
-Measures the phase difference between two radio signals
-Provides radials in degrees oriented to Magnetic, True or Grid North
-Frequency range:
VHF: 108.00 MHz - 117.95MHz with 50 KHz spacing
ILS freqs: 108.10 - 111.95 Localizer (VHF)
330.95 - 334.70 Glideslope (UHF)
13 Explain how the aircraft receives signals from the VOR?
-Equipment on the aircraft receives two 30 Hz signals from a VOR ground station.
-Measures phase difference between them.
-Converts phase difference to a radial which is displayed on a Remote Magnetic Indicator (RMI).
13 How do you plot a VOR?
To plot a VOR, the radial is plotted from the VOR with a protractor aligned to the station North (must be found in GPH 205).
13 How are VORs aligned?
VORs are normally aligned to magnetic north in Southern Domestic Airspace and true north in Northern Domestic Airspace.
13 What does VOR stand for?
Very High Frequency Omni-Directional Range (range meaning area not distance).
13 What is the theoretical accuracy of the VOR?
-Theoretical accuracy ± 2° - 5°
-accepted 402 Sqn accuracy ± 2.5°
13 What are the limits of the VOR?
-Line of sight
-Affected by a variety of site effects
echoes from hills, buildings
magnetic anomalies
-80° cone of confusion
13 What does TACAN stand for?
Tactical Air Navigation.
13 What is a TACAN useful for?
-Military, line of sight radio navigation aid
-Continuous range and bearing information
-Theoretically more accurate than either VOR & ADF
13 What methods of calculations are used for TACANs?
-TACAN operation can be broken down into two parts:
Radial (azimuth) calculation
DME (distance) calculation
-Radial calculation is different than either ADF or VOR methods.
-DME calculation is similar to radar ranging (e.g. time the signal takes to go out and back equates to a distance).
13 How does DME obtain range?
-Distance measuring equipment (DME) obtains slant range from the ground station by using an interrogation-response technique.
-The airborne equipment calculates range by sending an interrogation pulse and waiting for a reply from the ground station.
-The time interval between the interrogation and the response is converted to range.
13 What are the capabilities and limits of a TACAN?
-Range line of sight (UHF);
-Maximum of 252 channels, consists of 126 mode X and 126 mode Y channels.
-A cone of confusion can vary from 60º-110º across depending on the ground site;
-Bearing accuracy ±3/4; and.
-DME is slant range, accurate ±1 nm.
-TACANs are normally aligned to magnetic north in Southern Domestic Airspace and true north in Northern Domestic Airspace
13 Where is the TACAN system on the CT-142?
-The TACAN antenna is located on the lower forward fuselage;
-The TACAN system is located in the secondary avionics rack; and
-The NAV/TAC controller located on the Pilot’s side of the glare shield panel.
13 What will happen if the VORs are not able to receive a signal (off, ILS or too far from the station)?
The needle parks at the 3/9 o’clock position.
13 What’s the difference between tuning up a DME channel and a TACAN channel?
-If you tell the pilot to tune up a TACAN channel, the bearing and distance information will be seen.
-If you have the pilot tune up a DME channel (from a VOR/DME station) only the distance will be given, no bearing information will be available.
13 What is the difference between tracking and homing?
You apply drift for tracking.
14 What two pieces of info do transponders provide to ATC?
Identification and altitude.
14 What is Mode 1?
Military; 2 digit ident code selected on control unit
14 What is Mode 2?
Military; 4 digit ident code selected on R/T
14 What is Mode 4?
Military; Legacy encrypted challenge and reply code
14 What is Mode 5?
Military; New cryptographically secured challenge and reply code (NOTE: Canada does not have this one)
14 What is Mode 3A?
Civilian; 4 digit ident (squawk code)
14 What is Mode 3C?
Civilian; 4 digit code and pressure altitude from DADC system (squawk code + altitude)
14 What is Mode 3S?
Civilian; 4 digit code and pressure altitude and other pertinent info (squawk code + altitude + requested info)
14 What does SQUAK XXXX mean?
Operate designated four-digit code ( dial in code)
14 What does SQUAK IDENT mean?
Engage transponder ident feature (press ident)
14 What does RECYCLE TRANSPONDER mean?
Aircraft data not displayed as expected, re-enter the code
14 What does RADAR IDENTIFIED mean?
Aircraft tagged and tracked
14 What does RADAR SERVICE TERMINATED mean?
Aircraft no longer under SSR coverage, resume normal position reports
14 What are the essential MODE 3 codes?
-7500 Hijack
-7600 Comm Failure
-7700 Emergencies
14 What is the primary transponder system on the CT-142?
The Collins TDR-94/94D transponder. Used for missions operated under civil ATC only.
14 What do the control heads provide a means for setting?
-ATC squawk codes;
-modes of operation;
-self-test operation;
-annunciators; and
-self-test diagnostics
14 What can Mode S do?
-16 million codes - each aircraft has its own unique signature
-Can provide ATC with additional requested data from FMS (hdg, speed, etc.)
-Can provide DATA LINK
-DATA LINK:
clearances and routing
weather and maps
aircrew can acknowledge by the push of a button
required in Europe and soon N.A. (civilian)
-Integral component of TCAS
14 What modes does the BENDIX AN/APX-100 (V) IFF/SIF posses?
-Mode 3/A and C
-Mode 1, 2 and 4
Provides military controllers with positive ID of friendly aircraft
Codes change as often as operations dictate
14 What is TCAS?
-Traffic Alert and Collision Avoidance System (TCAS) also known as ACAS
-ACAS manufactured in the US is called TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM (TCAS)
-TCAS equipped aircraft interrogate other aircraft with at least mode A (mode A will have bearing only, no altitude)
-Directs pilots to take corrective action without the input of ATC
14 How does the TCAS on the CT-142 work?
-Requires other aircraft to have at least a Mode C transponder
-If the IFF system is selected, the TCAS system will not be operational as the Mode S is put into standby mode
-TCAS control panel and the corresponding TCAS display is integrated with the Vertical Speed Indicator
-TCAS commanded avoidance maneuvers will most often involve a climb or descent
14 What are the principles of operation of the radio altimeter? (RADALT)
-Pulse is transmitted from aircraft to ground and is reflected back
-Time taken to complete cycle is measured
-Time converted to a distance = height
-Absolute Altitude displayed in feet
-Does not contain temperature and density errors unlike pressure altimeter
14 What are the basic components of the radio altimeter (RADALT)?
-Receiver/transmitter
-Indicator
-Antenna system
most systems have two antennas
allows for continuous transmission/ reception
14 What is the operating range of the RADALT and how is it displayed?
-Operating range - 0 - 2500 feet
-Flight Deck: displayed on Electronic Attitude Director Indicators (EADIs)
0 - 2500 feet
10 foot increments above 200 feet, 5 foot increments below 200 feet
-Nav Consoles: displayed on Altimeter
0 - 2500 feet
10 foot increments
14 What does the Ground Proximity Warning System (GPWS) do?
-Provides a visual, and synthesized aural voice annunciation
-GPWS is active whenever aircraft electrical system is powered (i.e. automatic)
14 What are the components of the GPWS?
-a computer unit (avionics rack)
-cockpit speaker and variable attenuator
-left and right side PULL UP/GPWS TEST -switch lights (glareshield)
-left and right side BELOW G/S (Glide Slope) -cancel switch lights (glareshield)
-GPWS flap override switch (pilot side console)
-the GPWS fail light (master caution panel)
14 Explain GWPS Mode 1?
-Excessive Sink Rate
-illumination of PULL UP GPWS TEST switchlights and repetition of aural “SINK RATE” annunciation.
-followed by “WHOOP - WHOOP PULL UP” if the rate of descent is not corrected
14 Explain GWPS Mode 2A?
-Excessive Closure Rate
-voice annunciation “TERRAIN - TERRAIN” is repeated and PULL UP GPWS TEST switchlights are illuminated
-if closure rate continues “WHOOP - WHOOP PULL UP” annunciation repeats
-after the aircraft has been pulled up, the “TERRAIN - TERRAIN” voice message will continue until an additional 300 feet of altitude has been gained
14 Explain GWPS Mode 2B?
-Excessive Closure Rate on Landing Approach
-in approach configuration with either landing gear or flaps extended
-altitude gain function is inhibited
-“WHOOP - WHOOP PULL UP” annunciation is replaced by “TERRAIN - TERRAIN”
14 Explain GWPS Mode 3?
-Altitude Loss after Take-off
-Penetration of altitude loss warning threshold provides a repeated voice annunciation “DON’T SINK” and illumination of PULL UP GPWS TEST switchlights
14 Explain GWPS Mode 4A?
-Proximity to Terrain, Gear Up
-activated upon clearing 700 feet AGL after take-off
-when warning envelope penetrated below 157 kts IAS with gear up, repeated voice annunciation “TOO LOW - GEAR” is heard and GPWS PULL UP TEST switchlights are illuminated
-above 157 kts IAS, voice annunciation “TOO LOW - TERRAIN” is heard and GPWS PULL UP TEST switchlights are illuminated
14 Explain GWPS Mode 4B?
-Proximity to Terrain, Flaps Up
-provides protection when gear is down and flaps not in landing configuration
-upon penetration of envelope below 130 kts IAS a “TOO LOW - FLAP” annunciation is repeated and the GPWS PULL UP TEST switchlights are illuminated
-above 130 kts IAS a” TOO LOW - TERRAIN” annunciation is repeated and GPWS PULL UP TEST switchlights are illuminated
14 Explain GWPS Mode 5?
-Descent Below Glideslope
-when aircraft descends below ILS glideslope, the BELOW G/S switchlights are illuminated and the voice annunciation “GLIDESLOPE” is repeated
-rate varies as a function of radio altitude and glideslope deviation
-may be canceled below 1000 feet by pressing either BELOW G/S switchlight
automatically rearmed by climbing above 1000 feet AGL
14 Explain GWPS Mode 6?
-Descent Below Radio Altitude DH
-aural annunciation “MINIMUMS - MINIMUMS” is given once when aircraft passes through the selected radio altimeter decision height bug setting between the altitudes of 1000 and 50 feet
-will not function again until aircraft has descended below 50 feet or climbed above 1000 feet
-may be inhibited during VFR approaches by setting DH bug to 0 feet
14 Which SSR mode does the Collins TDR-94/94DATC use?
Mode S.
Common errors in troubleshooting
Poor Goal-Setting
Lack of Awareness
Failure to Consider The Implications
Poor Planning
Failure to Act
Lack of Knowledge
PPFFLL
The “Four Point System”
a troubleshooting methodology to be used whenever a system isn’t operating as advertised. This methodology was designed to minimize the exposure of the crew and aircraft to undue risks and stresses
Initial actions
Analysis
Corrective actions; and
Follow-up actions
Initial Actions
provide awareness of an actual or suspected equipment malfunction and conduct appropriate first reactions.
should inform the crew as soon as possible
Any quick reaction or memory items pertaining to the situation shall be carried out
*Confirm with instructor if simulated problem
If it is a system degradation, considerations must also be made for urgency of the situation vs. degradation before informing the crew
Analysis
detailed awareness and understanding of the actual or suspected equipment malfunction
-scanning mission kit to identify all affected systems
-noting all observed malfunctions
-noting system status (status, message history, alert area, satellites tracking
-confirming switch selection
-confirming recent maintenance
-consulting publications and checklists to ensure all checklist items were carried out properly
-inspecting CBs
Corrective Actions
attempt a rectification of the malfunction.
Actions can include the following but not limited to:
> turning system OFF and then ON
> resetting/rebooting / reinitializing the system
> redoing all initial checklist items for the system
> passing control of the system to another crew member
Follow-up Actions
system malfunction cannot be rectified.
The crew must make a decision if the flight/mission can continue
This will require coordination between the Aircraft Captain (AC) and the Mission Commander (MC/Lead student). Ultimately,
the AC is responsible for the safety of flight while the
MC is responsible for effective mission completion.
1- Safety of flight
2 - Major mission degradation
3 - Minor mission degradation
22 Safety of flight
1- Safety of flight: The affected system is required for safety of flight, therefore the flight/mission must be aborted and the crew shall RTB or land at the nearest suitable aerodrome (AC’s decision);
22 Major mission degradation
2 - The system malfunction is imposing a degradation that makes it impossible to complete the mission, therefore the flight/mission must be aborted and the crew shall RTB (MC’s decision); and
22 Minor mission degradation
The system malfunction is imposing a degradation that doesn’t make it impossible to complete the mission, therefore the flight/mission will continue (MC’s decision).
15 What is the GPS
Space based radio navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.
15 What are the basics of GPS
Provides highly accurate 3D position
Provides velocity vector and time
Global coverage
Continuous availability
Passive service (receiver)
Unlimited number of users
Somewhat resistant to interference
spread spectrum
Allows common grid reference
15 The Global Positioning System consists of three distinct segments:
Space Segment
Control Segment
User Segment
15 Control Segment consists of:
5 unmanned monitoring stations located around the world:
Passively monitors the satellites in view and collects range and time data transfer
One Master Control Station (MCS) in Colorado Springs (plus two backups one in California and one in Maryland):
Collates satellite data from the monitoring stations on the satellite’s clock drift and orbital position.
It uses this information to send corrections to the satellites (if necessary) and predict the satellite behaviour over the next few hours.
14 What are the RADALT basic components?
-Receiver/transmitter
-Indicator
-Antenna system
-most systems have two antennas
-allows for continuous transmission/ reception
15 What are the system segments of a GPS?
-Space Segment
-Control Segment
-User Segment
15 What are the basics of GPS?
-A space-based radio navigation system.
-Widely used in a large variety of military and civilian applications.
-Principle: Measures ranges between the receiver and satellites.
15 What does the space segment consist of?
-Final constellation baseline provides 31 satellites for world-wide coverage
-6 orbital planes of 4-5 satellites (non-uniform)
-6 to 11 satellites are always in view
-Orbit period is 12 hours (approximately)
-Orbit altitude is approximately 20,200 km
15 How do the GPS satellites orbit?
-GPS uses semi-synchronous orbit
-2 Satellite orbits for 1 Earth orbit
-Satellite advances 4 mins each day WRT local time
15 What does the User Segment consist of?
-Antenna
-Signal processing equipment
-Oscillator
-Computer
15 What are the characteristics of Standard Positioning Service?
-Civil users and some military
-Coarse acquisition (C/A) on L1 frequency
-Interim use of L2 frequency for carrier phase
-7.8 m error
-Civil accuracy degraded further when national (i.e. US) policy dictates
15 What are the characteristics of Precise Positioning Service?
-Military
-C/A on L1 and P/Y on L1 and L2
-≤ 5.9 m accuracy
-Anti-jam (spread spectrum) and anti-spoof (Y code) all Block IIs
-Requires decryption to access full capabilities
16 What two solutions are possible with three satellites available?
-The receiver can reject one position based on its relative position to earth or it has an impossibly high velocity.
-We can also use the earth and a Baro altimeter (for altitude) instead of a third satellite.
16 What would a fourth satellite be used for?
(i) absolutely resolve the ambiguity due to the two-position possibility and
(ii) resolving the errors inherent in the receiver clock.
16 Describe the capabilities of the GPs clock?
-MCS controls GPS time using Caesium (Cesium) clocks
-Constantly updates the satellites’ clock to the correct time
-Clock drift in between updates is predicted and passed to users to allow more accurate positioning
-Each satellite has four atomic clocks
2 caesium and 2 rubidium
-One nanosecond clock error = one foot position error
16 What is coarse acquisition (C/A) code?
-available to all users of GPS
-Also known as clear access code or Gold Code
-Total of 32 codes assigned to GPS satellites
-Each satellite has its own unique C/A code to allow for satellite identification by receivers
-C/A code is recycled as satellites are replaced
-C/A code is 1,023 bits long (chips) and is transmitted at the rate of 1.023 Megabits/sec
-Repeated every millisecond
-Provides position accuracy of 13.9 meters 95% of the time
-Transmitted on the L1 carrier frequency only
16 What is P code?
P Code has a 10.23 Mega Bit/sec transmission rate and is broadcast on both L1 and L2 frequencies. This allows greater accuracy in two ways:
-the higher bit rate allows for improved sampling and increases accuracy
-the fact that it is broadcast on the 2 carrier frequencies allows sophisticated receivers to compare the arrival time of both carriers and correct for atmospheric refraction.
Accuracy is less than or equal to 6.6 meters 95% of the time
16 What is Y Code?
-US Military can encrypt the P Code which is known as Y Code
-P Code requires a much more sophisticated receiver than that required for C/A code
-Y Code requires crypto capability
Encryption for the P Code is available to US military and limited allies only
16 What are the operating and transmitting frequencies for the satellites?
Operating frequency = 10.23 MHz
Transmitting frequencies:
L1 is 154 times 10.23 MHz = 1575.42 MHz
L2 is 120 times 10.23 MHz = 1227.6 MHz
16 What are the capabilities of the Civilian L2 GPS?
-2nd civilian use freq
-Improved accuracy of navigation
Faster signal acquisition
Easy to track signal
Enhanced reliability
-Acts as a redundant signal in the case of interference
-Allows for the removal of atmospheric delay error
-GPS Block IIR-M capability
16 What are the capabilities of the Military (M Code) GPS?
-Transmitted on the same L1 and L2 freqs as the P-Code
-M-Code does not require the C/A code to achieve lock unlike the P-Code
-Two distinct signals sent from two distinct antenna
wide angle antenna
high-gain directional antenna which is
intended to be aimed at a specific area.
-Local signal strength is increased by 20 dB
-Makes the signal more difficult to jam
-Block IIR-M satellites transmit the earth code portion of the M-Code
-Spot beam capability – GPS Block III
16 What are the capabilities of the Safety of Life (L5) GPS?
-Band reserved exclusively for aviation safety services
-Higher Transmission power than L1 or L2C (around 3 dB more)
-Improved signal structure for better performance
-When used in combination with L1 C/A and L2C, L5 will enable sub-meter accuracy without augmentations
16 What are the capabilities of the Civilian L1 (L1X) GPS?
-C/A code modernization with newer capabilities
-Implementation provided C/A code to ensure backward compatibility
-Assured of 1.5 dB increase in minimum C/A code power to mitigate any noise floor increase
-Non-data signal component contains a pilot carrier to improve tracking
-Ensures civil interoperability with other systems i.e. Galileo
16 Describe Pseudo-Random Codes? (1 of 2)
-Satellites and receivers are synchronized
-Generating the same coded signal at the same time
-Receiver then compares the received signal to its self-generated signal to come up with a time difference and thus a range
-Pseudo-random sequences are repeated every millisecond
-Referred to as pseudo-random code (or noise)
16 Describe Pseudo-Random Codes? (2 of 2)
-Since GPS signals contain very little information, just timing signals and a Nav message (explained later), they can be sent at a low power and received using a very small antenna. GPS signals are in fact so faint they don’t register above the earth’s inherent background radio noise
Since we know the pattern of the receiver pseudo-random code and compare it with the background noise, we can look for areas where both are doing the same thing.
-We divide up the signal into time periods (chipping the signal) and marking all the periods that match. From this we can generate a comparison pattern for the satellite signal.
-Thus, Pseudo-random codes eliminate the need for large antennas and powerful transmitters. They allow the GPS system to operate with low power and allows for the use of small receiver antennas.
16 What is in the navigation message?
-Contains satellite ephemeris, clock data, almanac, and other information about the satellites and their signals.
-Contains the info required by the receiver to perform the operations and computations required to navigate using GPS.
-The message is superimposed over the C/A and P codes.
-It is divided into 300 bits per sub-frame, 5 sub-frames per frame, and 25 frames per message. Each message is 37, 500 bits long.
-At a transmission rate of 50 bps, it takes 750 seconds, 12.5 minutes, to transmit an entire almanac message.
-Each 30 second frame begins on the minute or half-minute as indicated by the atomic clock on each satellite.
16 What is the ephemeris?
The predictions/updates of current position of an individual satellite’s orbital position, that is transmitted to the user in the Nav message. Usually updated hourly by the MCS, transmitted to that particular satellite, which then transmits the info about itself to the user.
16 What is the almanac?
A catalogue of ephemeris data, for all the satellites, continually updated in the user receiver, as new individual satellite ephemeris data is received. The almanac tells the user where in the sky, the approximate position of each satellite is.
16 How are GPS satellites initially selected? (1 of 2)
-Initial start-up uses almanac data and/or operator entered position, velocity, and time (incl. date) (PVT).
-Chooses the best four satellites within its horizon.
-If the receiver does not have PVT or almanac data it goes into a “Searching the Sky” mode.
16 How are satellites selected? (2 of 2)
-Using a preprogrammed sequence the receiver picks a particular satellite and begins searching for its unique C/A code.
-The inability to find a satellite also precludes other satellites due to constellation geometry.
-Once a particular satellite is found the memory will tell it what others are available.
-In multi – channel receivers the GPS looks for many satellites at the same time and chooses the best based on geometry.
16 How are GPS satellites acquired?
-The receiver now knows what C/A codes it will search for.
-Estimates the phase shift required for the time difference.
-Estimates the Doppler shift required for the relative speeds.
-The code and carrier tracking loops now start to lock onto the signals.
16 What is a tracking loop?
The system within a receiver that generates its own signal then tries to match it with that of the incoming signal.
16 What two factors does the tracking loop attempt to compensate for?
-Phase shift caused by time differences
(Code Tracking Loop)
-Doppler shifts caused by relative speed changes
(Carrier Tracking Loop)
16 Explain the code tracking loop?
-C/A code search commences at the phase shifted point allowing for the time lag from satellite to receiver.
-Allows reception of weak signal and helps to offset gain limits from a relatively small antenna.
-Code lock is when the two signals match and is also the point of highest signal to noise ratio. This point is maintained for the remainder of the flight.
16 Explain the carrier tracking loop?
-The receiver uses a crystal oscillator to develop a frequency which it adds to the incoming frequency to compensate for Doppler shifts due to motion.
-The receiver can now extract the navigation message from the carrier.
Any further Doppler shifts equate to relative motion changes.
16 What technique does GPS use to calculate difference in timing accuracy between satellite and receiver?
Pseudo-Ranging
A.K.A. Clock Bias
16 How long does it take to receive the entire Navigation Message?
12.5 minutes
17 How many GPS errors are there?
Three
-User Range Error
-Multi-Path Error
-Dilution of Precision
17 What two TYPES of errors compose GPS errors?
-The first error is the measurement of the distance from the satellite to the receiver
User Range Error (URE) Also referred as User Equivalent Range Error (UERE)
-The second error is induced by having less than perfect fix geometry
Dilution of Precision (DoP)
17 List the types of User Range Error?
-Satellite Errors
Clock drift error should not exceed 2 m 95% of the time
-Control Segment Errors
Inaccurate ephemeris data gives errors up to 2.5 m 95% of the time (Over 8 hour period)
-Receiver errors make up the largest portion of User Range Error.
-Atmospheric Modeling is the largest cause of error: (Ionosphere and Troposphere)
-Multi-path errors
Associated with antenna location, and vehicle dynamics
17 What is total User Range Error expected to be?
-P Code up to 6.6m 95% of the time
-C/A Code up to 13.9m 95% of the time
17 Explain the Dilution of Precision error?
-Comes from having a fix geometry of less than 90 degrees.
-Airborne we are concerned with 3-dimensional position error.
-DOP is considered to be a coefficient of 2.54, 95% of the time.
17 What is the Total System Accuracy?
-P Code
DOP times URE is (2.546.6)=16.8m 95% of the time
-C/A Code
DOP times URE is (2.5413.9)= 35.3m 95% of the time
17 What are the types of GPS Receivers?
-Sequential receivers - 1 or more channels. 2 channel receiver is the minimum for P code reception.
-Multiplex receivers - one or more channels plus software channels.
-Continuous receivers - four or more channels.
-Cost comparison:
Sequential to Multiplex to Continuous
Cheap to expensive and simple to complex
17 What are differential GPS systems used for?
-Ground Reference stations to eliminate GPS errors.
-Accuracies to 1m
-Used for construction, mapping, surveying, air navigation and any where precise positioning is required.
17 What are two types of DGPS?
-LAAS – Local Area Augmentation System
Ground based
-WAAS – Wide Area Augmentation System
Space based
17 What are the characteristics of LAAS?
-Used for standard RNAV approaches.
-No unique aircraft equipment required.
-No specific pilot qualifications.
-RAIM checks required.
-No specific frequencies required to be dialed up.
17 What are the characteristics of WAAS?
-Aircraft must have a WAAS capable FMS (CT-142 is equipped with this).
-Both pilots must be qualified to fly a WAAS enabled RNAV (LPV minima) approach.
-LPV (Localizer Performance with Vertical Guidance) is the highest precision GPS instrument approach currently available.
-Lateral guidance is equivalent to a localizer and uses ground-independent electronic glide path
-It’s an approach with vertical guidance (APV) to distinguish it from a precision approach (PA) or non-precision approach (NPA).
-Specific channel is required – it should come up when the approach is selected in FMS. Channel is indicated on GPH 200 approach plate in top left corner (example on next slide).
-No RAIM check required.
-If WAAS system is unavailable, will default to LAAS system
17 What does the Emulated GPS receive inputs from?
-UNS-1C GPS to Emulated GPS:
Aircraft GPS provides GPS Px, time, Satellite information, system status, altitude, G/S, and Ground Track
-Inertial Reference Unit to Emulated GPS:
TAS, which is supplied to the IRU from the DADC.
17 What does the Emulated GPS put out as information?
-Position and time
-Satellite information (How many satellites are visible, how many the GPS is tracking and which satellites they are)
-Altitude
-Ground track
-Ground speed
-TAS
17 How many waypoints can the emulated GPS store?
20
17 What does a GPS with 3 satellites mean?
-Altitude information no longer available
-Lat/Long still valid
17 What does a GPS with 2 satellites mean?
-Lat/Long not valid
-GPS not usable. Revert to degraded ops
17 What happens when the GPS fails?
-GPS position become erratic and varies
randomly with large errors.
-Time on NTS continues to operate
18 Where is the standby compass located, and what is it for?
Located on the windshield centre post
It provides a back-up in the event of an AHRS failure and provides an independent cross check of the AHRS.
18 What are the AHRS components?
Remote Compass Transmitter - Flux Valve
Attitude Heading Reference Unit – AHRU
AHRS Control Panel
18 What does the flux valve do?
The Flux Valve detects the magnitude and direction of the earth’s magnetic field (H component), and converts it to electrical information which is used to align the Directional Gyro (DG) in the AHRU.
18 Where are the remote compasses located?
Remote compasses are located in the wing tips
This gives them the maximum separation from the magnetic disturbances created by the aircraft structure and electrical system.
18 Where is the AHRU (Attitude Heading Reference Unit) located?
located under the floor, aft of the air-stair door
18 There are two AHRS controllers, located on the flight deck centre console.
The controllers allow for AHRS:
-system test
-system configuration
-basic system monitoring
18 AHRS Inputs
TAS, from the appropriate ADC via the ASCB data bus
Magnetic heading information, from the flux valve via the AHRS Control Panel
18 AHRS Outputs
Flight Instruments:
EFIS
ADIs & HSIs
Pilot/Co-pilot RMI
Flight Guidance Computers (Auto-pilot)
Air Data Computers
Other aircraft systems
Advisory Displays
FMS
18 Doppler definition: ______ observed due to ________ of the source and/or receiver.
Frequency shift, relative motion
18 There are four factors that determine the amount of Doppler shift
- FREQUENCY of the transmitted signal (fo). The higher the frequency the greater the shift (directly proportional).
- RELATIVE VELOCITY between the transmission source and the receiver (V). Note this is RELATIVE velocity, not actual velocity, as both the receiver and transmitter may be moving. (directly proportional).
- SPEED OF PROPOGATION (C). Sound waves/radio waves ‑ speed of sound/speed of light (inversely proportional).
- ANGLE between direction of movement and the line of propagation from TX to RX () (directly proportional). The bigger the angle the smaller the doppler shift (cos 90 = 0), (Cos
18 ________ technique is used to compensate for changes in aircraft attitude.
JANUS
18 What is the JANUS technique
Uses 3 or 4 beams (two forward and one or two backward).
Compares the different readings to determine more accurate groundspeed and drift.
Since front and rear beams are compared in the JANUS system, ground speed errors caused by a climb or descent will cancel each other because the front and rear beams will show the opposite error.
18 What is the pitch error compensation?
In level flight the front beams sense an increase in frequency while the rear beams sense a decrease in frequency. If diagonally opposite beams are compared, the frequency difference is equal to twice the Doppler shift of one beam
18 what is the 4 Beam Janus Roll Comparison
The same thing happens with roll, producing very little error. To further reduce errors due to roll, the beams are transmitted in a conical pattern.
This pattern reduces the amount of change in the depression angle during small roll movements as well as ensuring the return signal overlap required to compare the beams.
18 Doppler Components
Receiver/Transmitter and Antenna
Signal Data Converter (SDC)
Emulated Control Display Unit (CDU)
Navigation Training System (NTS)
18 Components - what are the functions of the SDC
-Determines Doppler shift of received signals
-Processes the signals and computes
along heading velocity (Vx);
across heading velocity (Vy);
vertical velocity (Vz)
-Converts velocity data into drift angle and
groundspeed
-Conducts signal to noise checks
-Performs system validity checks and sends status
signal to Navigation Training System (NTS)
18 What do the following annunciators on the doppler CDU mean
SELF TEST
MEMORY
DPLR MALF
SELF TEST: when system is in self test
MEMORY: loss of valid return on two or more beams
DPLR MALF: system malfunction during S/T
18 Components - What does the Navigation Training System (NTS) do
The NTS generates the software for the Emulated Control Display Unit (CDU).
18 NTS Inputs
Antenna radiates RF signals
Receiver mixes reflected signal with transmitted frequency and passes difference to SDC
SDC converts info to drift and groundspeed and passes it to NTS
SDC performs validity checks and sends status to NTS
18 NTS Outputs
System info from NTS to all emulated Control Display Units (CDU).
Drift and groundspeed displayed in Doppler area of Data Information Display (DID).
Mode control signals from CDU sent to NTS which sends them to Doppler hardware via SDC.
18 What are the Drift/Groundspeed Limits
Drift: 20 degrees maximum on flag display
Ground speed: 25 to 650 kts
(666 kts during self test)
18 What are the Power Requirements
28V DC
115V AC
26V AC @ 400 Hz
