5 Flashcards
If an aircraft is IFR certified, what must be different about the captain and FO’s instrument systems?
Systems fed separately
Where is the PFD found in a glass cockpit?
On the outboard side
How many screens are on a basic EFIS system?
6
What are the basic T arrangement instruments and their relative position?
ASI ADI ALT
TBI HSI VSI
ASI, ADI, ALT and HSI are the basic T instruments
EADI can also be referred to as?
Primary Flight Display (PFD)
EHSI can also be referred to as?
Navigation Display (ND)
What is 1 atm in hPa? and in inHg?
1 Atm - 1013.25 hPa
1 Atm - 29.92 inHg
What instruments use pressure to display readings?
ALT, ASI and VSI
How many degrees does the temp decrease per 1000ft?
Decrease 2℃ per 1000ft
What is the standard temp at sea level?
15℃
What pressure do altimeters use to display altitude?
Static pressure
What is the pressure at 18,000ft, 36,000ft and 54,000ft compared to sea level?
18 - 50%
36 - 25%
54 - 12.5%
Are altimeters more or less accurate/sensitive at low altitudes?
Less accurate/sensitive
what is used at low altitudes to give an altitude readings?
Radio altimeter
What does the transducer do in the radio altimeter?
Analogue to digital conversion
What happens to the aneroid capsule/bellows as altitude increases?
It expands, this is mechanically linked to the pointer
Why are the bellows corrugated?
Greater surface leading to higher sensitivity
Where is the static pressure fed to in an altimeter?
The case
Large aircraft don’t have bellows what is used instead?
Air Data Computer (ADC)
Why does the barometric attitude need changing?
As there is differences in local pressure
In cruise what should Q code be changed to?
Changed from QNH/QFE to QNE at cruise which is the ISO standard
What is being fed into the ASI?
The pitot pressure and static pressure
What is the pitot probe connected to in an ASI?
Bellows/aneroid capsule
Where is the static pressure fed to in an ASI?
The case
What do the green, white and yellow band signify on the ASI?
Green - normal operating range
White - Speed range with full flaps
Yellow - Caution range, only done in smooth air
What does the airspeed limit depend on?
- Velocity Max Operating speed (VMO)
- Max Mach Operating speed (MMO)
How dos a VSI work?
Static pressure supplied into the case and the calibrated metering unit. Utilises differential pressure
What is the problem with a VSI?
There is a lag
what is a mach meter?
A dial that displays speed as a ratio of true airspeed and local speed of sound
What is another name for SAT and what is SAT?
Outside Air Temp (OAT)
Static Air Temp (SAT) is the temperature of undisturbed air
Where is the only place where TAT and SAT are the same?
When the aircraft is on the ground
TAT is usually higher
Where would TAT and SAT be displayed?
ECAM
What instruments require pitot and/or static pressure?
ALT - Static
ASI - Pitot and static
VSI - Static
Where are Static ports located?
Out of relative airflow, in an area of smooth airflow to get undisturbed readings
What is the difference between the measured and real static pressure called?
Static Source Error (SSE)
What causes SSE?
SSE is caused by:
- Shape of aircraft
- Speed
- What config aircraft is in i.e. flaps full gear down for landing
How is SSE rectified?
With an ADC
When would static ports be covered?
When cleaning or painting the aircraft
What is the combined ADC and IRU called?
Air Date Inertial Reference Unit (ADIRU)
What effect does side slip have on the static pressure?
The port on the side of the slip will have a higher reading than usual
How are the static ports connected to give an average reading during a side slip situation?
Via a cross porting tube, the right and left port are connected using this
What does the baffle prevent in the pitot probe?
Contaminant ingress
What are some additional feature of a pitot probe?
- Drain hole at the lowest point
- Heater to prevent ice build up
What does the alternate static selector valve do?
Allows the captain to use the FO’s system for the instruments in the event of failure.
Also used on small aircraft with IFR certification
Aircraft that fly at higher speeds and altitudes require what extra instruments?
- True airspeed
- Mach meter
- Air temp indicator
Any data sent to ECAM is sent via what?
Air Radio INCorporated 429 (ARINC429)
like a data bus
Some aircraft have a 3rd ADC what is the purpose of this?
- Redundancy
- If there are reading discrepancies then the 3rd computer will help to decide the true reading by comparing its reading with the other 2
What is hot standby?
Hot standby is when a part is ready-to-use auto online if needed
What do Air Data Modules do?
Convert Analogue to digital then send along ARINC429
Why is the air data module located near to the static port?
To save weight
What does the DMC do?
Display Management Computer takes data from ARIN429 and converts it into graphics
When would a leak test be performed?
After the system has been disturbed
When is the Q-code changed?
At the transition level
What does encoding altimeter do?
Sends a digital code to the aircraft ATC transponder. It replies to the ATC radar with altitude data
- Gives the ATC info on who the aircraft is (Squawk) and how high
What principle does a servo altimeter work off?
Induction pick off
- E and I bar
What is another example of the E and I?
Linear Variable Differential Transducer
Calibrated Metering Unit is also called?
Capillary tube
What is added to a VSI to alleviate lag?
Dashpot - Weight between two springs
Instantaneous Vertical Speed Indicator
How long does it take a gyro to run down?
Up to 20 mins
ADI’s utilise what type of gyro?
Vertical axis gyros
What does vertical and horizontal refer to in vertical and horizontal gyros?
The axis about which the mass rotates
HSI’s use what type of gyro?
Horizontal/driectional gyro
What would a rate gyro be used for?
Rate of turn indicator
How many laser ring gyros are required on an aircraft?
3 are needed:
- Roll
- Pitch
- Yaw
What is the standby gyro powered by?
The battery
What 3 things affect the rigidity of a gyro?
- The mass
- The rotation speed
- The distance between axis and the mass
What factor is used to improve rigidity on an aircraft?
The speed of rotation
20,000 to 24,000rpm
Gyros have how many gimbals to give an indication of the aircraft attitude?
One or two
What dictates the degrees of freedom in a gyro?
The number of gimbals
What gyros are needed on aircraft?
Earth tied gyros
How many degrees of freedom does a rate gyro have?
1
A rate gyro will have how many degrees of freedom when held by springs?
1.5
What is a tied gyro?
Gyro about a fixed axis
What is rigidity?
The gyros ability to maintain its axis
Gyro precession depends on what?
- Axis the force is applied too
- Direction of spin
Precession is felt 90° to the force and in the same direction as the spin
What may sticks be equipped with as a method of stall warning prevention/warning?
- Stick pushers
- Stick shakers
What type of gyro is a laser ring gyro?
Rate gyro
How many gyros are in an ADIRU and why?
3, one for each axis
What is gyro wander?
Deviation from the fixed axis, it is called drift or topple depending on the axis
What is gyro wander caused by?
Imbalances, can be from wear and tear
What are the 3 methods of correcting wander?
- Pendulous vanes
- Rotating balls
- Electrolytic switches
What are the advantages of laser ring gyros?
- Less maintenance
- No moving parts
How does a laser ring gyro work?
Difference in time of arrival at detectors. Proportional to the aircraft movement
The IRS has how many RLG and accelerometers and where is it located?
- 3 RLG
- 3 accelerometers
- Located on the longitudinal axis
What will disturb the back up compass on the aircraft?
Magnetic fields
What is given on the HSI?
- Heading
- Glidescope
- Localiser
- Weather
- To from indicator
- Course selector point
How are turn and slip indicators powered?
28v dc
What does a turn and slip indicator not show?
Pitch
How do you know you are in a co-ordinated turn?
The slip indicator will remain in the centre position
Standby compasses are known as what?
E2B
What does the lubber line show?
Heading of the longitudinal axis
What are the two types of heading?
True and magnetic
What is variation?
The difference between the true and magnetic compass readings
How do you remember deviation and variation?
Cadburys - Compass
Dairy - Deviation
Milk - Magnetic
Very - Variation
Tasty - True
All compasses point to what?
Magnetic north
What occurs to the magnets as their position WRT magnetic north changes?
Inclination, they become redundant at a certain angle
Where will the flux detectors be found?
Wing tips or vertical fin
How must all magnetic direction indicators be installed?
In a way that their accuracy is not affected excessively by the aircrafts magnetic field and vibration
What can be said about hard iron magnetism?
Permanent form of magnet
- Hard to de-mag
- Easy to mag
what can be said about soft iron magnetism?
Temporary magnetism
What does a direct reading compass contain?
All parts necessary to read magnetic heading
Why is the direct reading compass filled with fluid?
to dampen the compass scale movements
what is the purpose of the expansion unit on a direct reading compass?
Compensates for fluid expansion by temp changes
Where is the direct reading compass located and why?
visible from each pilot seat
When does a direct reading compass read perfectly?
- Level flight
- Constant speed
What is the purpose of a compass deviation card?
For pilots to make adjustments in-flight
The cable for the light in the compass is what to stop magnetic interference?
Twisted and screened
What eliminates the problems with direct reading compass?
Directional gyro
What is the main component of a remote compass?
Flux valve located at wing tips or vertical stab
Where will a compass swing test be performed?
Designated compass swing base
What is the flux valve connected to?
Remote compass
What compensates for SSE?
The ADC
When will a stall waring go off?
Before a stall
Is alpha max constant?
No it varies
Where must the stall warning operate?
At least 5kts or 5% above the stall speed
AoA info is taken from what?
AoA vane
What are the warnings of a stall given to the pilots?
Audible and visual
What is flight data shown on in a glass cockpit?
Electronic Flight Instrument System (EFIS)
How are Multi Functional Displays (MFD) controlled?
By two (3rd for the engineer) Multi Function Keypads (MFK) one for each pilot
How may warning info be displayed?
In order of priority, warning over a caution
How is the brightness of the EFIS controlled?
Brightness control knob on the outboard side
Where are the display management computers located?
In the avionics bay
What are the benefits to EFIS?
All data represented in a user friendly and precise manner
What does a basic EFIS require?
- Symbol generators
- Displays to show data
- Computer to process info
- Sensors
What is the function of the comparator unit?
Compares info from the Captains and the FO’s sensors
What does the PFD show?
- Airspeed
- Heading
- Attitude
- Altitude
- Vertical speed
- Radio altitude
- Flight mode annunciation
- Flight guidance cues
What does the ND show?
- VOR mode
- Approach mode
- Map mode
- Plan mode
What would a warning display show?
- EICAS/ECAM
- Communication messages
- Memos
- Warnings
- Cautions
- Advisories
What are the two types of map display?
Rose and arc
On what display is the FMC info shown?
The EHSI
When will the FLT DIR be used?
Flying manually
If there are not issues with autopilot, what will the autopilot/autoland status be?
Land 3 - Fail operational mode
What does VOR stand for?
VHF Omnidirectional Range
When is weather data present on the screen?
When in expanded VOR or ILS modes
How can an EFIS self test be conducted?
Test switch, Central Maintenance Computer (CMC) or Central Maintenance Computing Function (CMCF)
When can an EFIS self test be conducted?
When there is weight on the wheels
The colours bars in EFIS test mode are presented during what mode?
PLAN on the raster presentations
In what order are cautions and warnings shown?
Warnings over cautions, then chronologically
What does each colour represent?
Red - Warning
Amber - Caution
Cyan - Advisory
White - Status
Green - Normal system status
Magenta - Info
What does green light mean in the landing gear system?
Down and locked
What is the purpose of auto-pilot?
Reduce pilots workload
How many methods of autopilot disengagement must be available to the crew?
2 or more
What is the Flight Director System (FDS)?
Guidance aid to the pilot during manual flight
What does the auto trim system do?
Maintains pitch stability during all phases of flight by changing the THS angle
The yaw damper will deflect in what direction to counteract dutch roll?
Opposite
What does flight envelope protection do?
Prevents abnormal flight conditions
What are the engines controlled by in auto throttle?
Full Authority Digital Engine Control (FADEC)
How quick is a correction control inputted after a disturbance?
50ms
What are the servos for ailerons?
Lateral Control Circuit Actuators (LCCA)
How is feedback from the actuators sent?
Via electrical signals
Full flight profile auto pilot requires sensors for what?
- Attitude
- Rate info
- Later movement
- Heading
- Speed and height
- Radio coupling
What is a duplex auto pilot system?
2 channels for each movement
What is the redundancy in duplex?
Signals are duplicated
What is the redundancy in triplex?
Signals are tripled and then votes are conducted if there is a discrepancy
Why are closed loop systems used on aircraft?
As they provide feedback
What does the outer loop of the autopilot system do?
Gives signals to the inner loop and is controlled by the autopilot or pilot controls
What does the inner loop do?
Controls the actuators
How does the autopilot know the position of the control surface?
Feedback due to the closed loop system
What does altitude hold mode utilise?
- Aneroid capsules
- E and I transducer
How do you know an aircraft is not properly trimmed?
Lots of input from pilot is required
What happens when autopilot is disengaged?
- Visual warning light
- Aural warning
What are the two types of auto-throttle?
- Autothrottle
- Autothrust
What auto throttle mode uses the FADEC and what one moves the levers?
- Auto throttle moves the lever
- Auto thrust uses FADEC
When can auto throttle modes be used?
All flight phases
What does fail operational mean?
One failure can occur but leaves the whole system still functioning
What is radio telephony?
Exchange of info using radio waves
What is the name for when you have an audible frequency and convert it to a carrier frequency?
Modulation
When would HF frequency be sued?
Long distance transmissions
When would VHF be used?
Short range comms
What is the frequency and the wavelength for:
- HF?
- VHF?
- HF 3 - 30 MHz 10m - 100m
- VHF 30 - 300 MHz 1m - 10m
What is the spacing between comms channels?
8.33KHz
What frequency are comms and what are nav?
- Comms 118 - 137 MHz
- Nav 108 - 118 MHz
What affects the HF transmissions?
- Time of day
- Ionosphere
What are the two types of radio equipment?
Transmitting and receiving
What does the length of the Ariel depend on?
The wavelength, typically 1/4 λ
What antennas may be fitted in the radome?
- Weather radar
- Glidescope capture
- Localiser track
Where would the SATCOM Ariel be located?
Vertical fin
What are the types of modulation?
- Frequency (FM)
- Amplitude (AM)
What is the ELT frequency?
121.5 MHz
What is the cabin inter phone used for?
For the flight crew and cabin crew to talk to each other
What is the service inter phone used for?
To allow the flight crew and ground staff to talk, located at maintenance points
What is SELCAL?
Private transmission sent to people that share the code
When can the flight inter phone be used?
Weight on wheels
What does ACARS stand for?
Aircraft Communications, Addressing and Reporting System
What is VHF used for?
Data and voice transmission over short distance
What affects the distance between VHF comms?
The altitude of the aircraft
What are the 3 VHF radios used onboard?
- One for the captain
- One for the first officer
- ACARS
How many frequencies can be selected at once?
2 one is active and the other is standby. Changed by pressing the transfer button
What does ACARS do?
Receives and transmits messages to company ops
What is the purpose of the electrical tuning unit in HF?
Changes the operating length of the antenna
Where is the HF Ariel located?
Vertical stabiliser
What are some safety precautions for HF?
- No one in the vicinity when operating
- Don’t operate during refuel/defuel
- Don’t operate in the hangar
- Couplers are pressurised
What has HF widely been replaced by?
SATCOM
What is a SELCAL code?
4 letters made up of letters of A thru to M excluding I
How is the pilot alerted of a message on the SELCAL?
- Audible chime
- Visual light
How many HF systems are fitted to long haul and short haul aircraft?
- 2 for long haul
- 1 for short haul
Do pilots have to continuously monitor SELCAL?
No
What does SELCAL use?
- VHF
- HF predominantly
What does each letter in SELCAL represent?
A chime of 300 - 1000 Hz
What can SATCOM be used for?
Data and voice transmission
What is done to SATCOM signals before transmission?
Encrypted
What does SatCom allow?
- Passenger calls, emails and internet
- Pilot contact to ATC
- Real time weather
- Most fuel efficient route
- Position and maintenance status to staff
What orbit do International Maritime Satellites have?
Geostationary
How many Ground Earth Stations (GES) can an AIRcraft Earth Station (AES) be logged into at once?
One at a time
Does a SatCom antenna move? If so by what?
Yes, it moves to always point towards the satellite via Beam Steering Unit (BSU)
What boosts the signal if the antenna is struggling to lock on to the satellite?
High Power Amplifier
How does the satellite know where the aircraft is?
ADIRU sends positional data
What are the 3 components in a SatCom network?
- Satellite
- GES
- AES
What VHF channel does ACARS use?
VHF channel 3
Are ACARS transmissions automatic or manual?
They are both
What are the two main ACARS networks?
- SITA
- ARINC
In flight, what is used for ACARS transmission if VHF is out of range?
Satcom
How do you know that ACARS is being used?
Comms panel will display ‘Data’ or ‘ACARS’
What frequency does the Underwater Locator Beacon (ULB) transmit at?
37.5 KHz
Where are Flight Data Recorders (FDR)/ Cockpit Voice Recorders (CVR) found, and what do they look like?
They are found behind the rear pressure bulkhead and are orange in colour
What does the FDR record?
Flight data, lots of different parameters several times a second
What do modern CVR’s and FDR’s use to save data?
Solid State Drives
How many flight hours must the CVR and FDR store?
25 flight hours
What can the CVR’s and FDR’s withstand?
- 1000℃
- 3400G
- 6000m depth underwater
When does the FDR and CVR start recording?
- Oil pressure signal
- Airspeed signal
What does the CVR use to record voice?
Cockpit area mic
What are the 4 channels the CVR records?
1 - Cockpit area mic
2 - Captains mic
3 - First officers mic
4 - PA audio
How many DC power supplies do FDR’s and CVR’s have?
2 supplies
What do Emergency Locator Transmitters (ELT) transmit and at what intervals?
Single output that gives info on longitude and latitude
Transmits signal every 50 secs for 24 hours at 406 MHz
Where are fixed ELT’s located?
Upper aft section of the fuselage
When would a portable ELT be used?
Removed with a life raft
What do ELT’s transmit to?
SARSAT
What frequency do the portable ELT’s operate on?
121.50 MHz and 243 MHz
What should the ELT’s be set to for flight?
Armed position
What tunes the size of the HF antenna?
Antenna tuning unit or antenna coupling unit
What system does SELCAL use?
VHF and HF
What does the ELT download when plugged in initially?
- Country of origin
- Unique ID code
What should ELTS’s be set too?
Armed position
What 3 things must the pilot know in relation to the aircraft position?
- Longitude
- Latitude
- Altitude
How many satellites must 3D nav be in sight of to give alt, lat and long information?
4 satellites
How often is the FMC updated?
Every 28 days
What is the slant range?
The slant range is the distance to the DME STN, the hypotenuse
If there is no wind what is the track the same as?
The heading
What do ground based radio beacons give?
Relative bearing between aircraft and beacon
What is Automatic Direction Finding (ADF) used to determine?
ADF used to determine the relative bearing of an aircraft to a ground station
What is the relative bearing?
Angle between the nose of the aircraft and the ground station
What is another name for an ADF beacon?
Non-directional beacons
What is ADF used for?
En-route navigation
What is the ADF displayed on?
EHSI or ND
What type of antenna is an ADF antenna?
Combined loop/sense
What are the frequencies for ADF’s inputted in to?
Control display unit (MCDU)
What are the two types of bearings?
‘TO’ and ‘FROM’
What are some of the VOR frequencies shared with?
ILS
How is the relative bearing determined from the VOR?
Two signals reference and variable. The phase difference is the relative bearing
What does the DME give the flight crew?
Slant range to and from a DME Non Directional Beacon
What is the DME range?
0 to 400 nautical miles
How is the slant range computed?
By the elapsed time interval between the instant of interrogation to the instant of reply
If a DME is out of range, what is displayed?
4 dashes
What are the 3 parts to ILS?
- Marker beacon
- Localiser
- Glidescope
What is autotuned into, when you tune into the localiser?
The glidescope
What frequencies are ILS signals found on?
108 - 112 MHz
Only on odd tenths i.e. 108.3 MHz
If you are on the centreline, what is the amplitude of the AM signals?
- To the left?
- To the right?
Centre - Amplitudes are equal
Left - 90 Hz predominates
Right - 150 Hz predominates
How does this work for the glideslope?
Same principle just in the vertical plane
What does one dot on the localiser represent?
1°
What is the carrier frequency of the marker beacon system?
75 MHz
What do the marker beacons represent?
How far the aircraft is from the runway
What colour and frequency of chime is:
- Outer marker?
- Middle marker?
- Inner marker?
Outer - blue 400 Hz
Middle - amber 1300 Hz
Inner - white 3000 Hz
Do you need to tune the marker beacon system?
No you don’t
How is the pilot alerted of the marker beacon?
Visual and aural
What are some primary radar systems?
- Radio alt
- Weather
- Primary ATC surveillance
What principle do primary radars rely on?
Radio wave reflection
What principle does secondary radar work off?
Interrogation response
What are the two components of secondary radar?
- Interrogator
- Transponder
What are the 3 secondary radar modes?
Mode a - ident
Mode c - ident + alt
Mode s - ident + additional data
What is the mode used for TCAS?
Mode s
How are radio waves transmitted?
Through waveguides
What is coaxial used for?
Comms transmission
What is the basic ATC transponder system often referred to when communicating on R/T?
Squawk
For the TCAS system to work, what mode transponder is required?
Mode S
What is the ident in mode S?
24 bit address
What does TCAS provide?
- Traffic advisories (TA)
- Resolution Advisories (RA)
- Vertical manoeuvre displays
- Aural info to the flight crew
What is the difference between TA and RA?
- TA is an alert of traffic
- RA is a warning and gives avoidance manoeuvres
Where may TCAS advisories be shown?
- EHSI/ND
- VSI
What altitude does the radio altimeter display height?
2500ft - 0ft
Why is a radio altimeter used?
As at low altitudes the barometric altimeter is inaccurate at low altitudes
How many radio altimeters antennas are there and where are they located?
There are 2 and they are on the under side of the fuselage
What are the main onboard users of GPS?
- FMS
- IRS
What are the 3 segments of GPS?
- User
- Satelite
- Control
What are the two main GPS services?
- Precision positioning service
- Standard positioning service
What does the IRS rely on to find speed and distance?
Uses 3 accelerometers, one for each axis, then integrates to get the speed and then distance
The IRU and ADIRU uses data from the FMC to do what functions?
- Initialise the aircraft position
- Calibrate the gyros and accelerometers
What does the ADIRU do initially?
- Verifies the validity of the entered initial position
- Compares initial to GPS
When would the align reset mode be used?
If the aircraft is moved during alignment
What does FANS utilise?
- GPS and SATCOM
What is CFIT?
Controlled Flight Into Terrain
The Ground Proximity Warning System (GPWS) provides the pilots with visual and audible warning of what?
The aircrafts closeness to terrain
What may be used to inhibit the GWPS?
Flap and/or gear position
What is EGPWS?
Enhanced GPWS
What is the additional mode of EGPWS?
Terrain mapping
How many modes are there in GPWS?
6
What does the FMS give?
- Nav
- Performance
- Display
- Guidance
What does the FMS calculate?
- Economy speeds
- Best flight alt
- Top of descent point
What guidance does the FMS give?
LNAV and VNAV
