ATPI Flashcards
What is Direct Lift Control
The elevator/stabilizer provides direct lift control. The elevator and stabilizer are aerofoils that by their positions create an upward or downward balancing force that controls the direct lift force from the main aerofoils thus determining the attitude of the aircraft around the lateral axis.
On some specific aircraft types, direct lift control also refers to an automatic varying of spoiler deployment to maintain a constant pitch attitude on the approach to land.
What are the effects of spanwise flow over a wing
creates wingtip vortices
reduced aileron efficiency
reversed span-wise flow upper surface at wingtip leads to disturbed airflow at wingtip leading to loss of lift and wingtip stalling
what are effects of wingtip vortices
Induced drag
wake turbulence
Down-wash over tail-plane
purpose vortex generators/wing fences
reduce span-wise flow over the wing, vortex generators increase control efficiency by turning airflow perpendicular to control surface. There is a marked increase in air density.
What do winglets achieve
They are designed to reduce induced drag. They dispense the spanwise airflow from the upper and lower surface often at different points, depending on the particular design, thus preventing the intermixing of these airflows that otherwise would create induced drag vortices.
How does forward C of G effect weight
Downforce applied to the tailplane in order to maintain level flight is effectively a weight and an increase in weight leads to an increase in stalling speed
How does weight effect descent profile
Heavier the aircraft, earlier the descent if you want to achieve the same IAS/Mn
Increase weight = Increase IAS/Mn = Increase ROD
If you want to descent at a Constant IAS/Mn = reduce the ROD to counteract the increased weight = earlier descent
Describe how you would design a swept wing
Thin, minimal camber, swept wing
How does sweep increase Mach Crit
Since the wing is responsive only to the velocity vector normal to the leading edge, the effective chordwise velocity is reduced (in effect, the wing is persuaded to believe that it is flying slower than it actually is).
Disadvantages of swept wing aircrafts
Poor lift qualities due to wing sweep, leads to higher stall speeds
Wingtip stalling
Why does wing swept wing stall from wingtip to root
Higher aerodynamic loading at wingtip due to taper
Reverse span-wise flow air leading to boundary layer separation
Increased induced drag with wing sweep at tips
Why are wings tapered
High aspect ratio wing - Low Drag, High Lift
Taper is compromise of strength vs weight to allow for the highest possible lift with minimal drag
High aspect ratio lift/drag properties
reduces induced drag!!!
Reduce wing tip stall
Increase Camber at wingtip (Change aerofoil section)
Increase angle of incidence at wing root
Describe Characteristics Mach Crit
Mach Buffet - Due to shockwave
Increase drag - breakdown of airflow (turbulent flow)
CP movement during Mcrit
High camber above wing shockwave forms forcing C.P rearwards
Swept wing aircraft, high camber at wing root - CP moves rearward down the wing
Stall speed with altitude
Increases - IAS increases due to compressiblity error on the instrument
Total drag is increased because the Mach no compressiblity effect on the wing disturbs the airflow over the wing which effectively reduces lift, increasing drag leading to a higher EAS requried
Deep stall
Swept wing - Wing tip stalling, wing loading and forward moving C.P
Forward fuselage acts as a wing creating further lift
Turbulent airflow envelopes tail-plane of aircraft
Counter act Deep stall
STALL WARNING
Stick shaker stick pusher
6 reasons for spoilers
- Aileron size is limited
- Thin swept wing aircraft’s - Large airlerons lead to wing twist at high speed
- Spanwise flow at high speed reduces aileron effeciancy
- Counteract adverse rolling moment with yaw
- Speedbrakes
- Lift dumping devices in rejected take off, places greater weight on wheels increasing braking efficiancy
Effect of flaps on take off run and second segment climb performance
Higher flap setting = Increased chord = Increased lift for low drag penalty = reduced Vs
Reduced Vs = reduced Vr (1.05Vs), reduced V2 (1.2Vs)
NOTE
Drag is not significantly increased because the angle of attack is low. However, the drag increment is higher when the aircraft is in flight and out-of-ground effect because of the aircraft’s angle of attack is much higher.
Initial and second-segment climb performance thus will be reduced with a high takeoff flap setting.
Parallel/Series Yaw Dampers
Parallel - Moves with rudders - makes it difficult for pilot inputs during engine failures on take off or a crosswind landing
Series - Does not move rudder pedals, and makes rudder inputs for the pilot easier during crosswind/engine failurs
4 reasons for varible incidence stabalizer
Balancing force for a large C of G range
Cope with large trim changes (configuration is changed)
Reduce elevator trim drag to a minimum
Balancing force for large speed range (run out of elevator)
What is an active control
Control surface that moves independently from pilot input - balance tab
Advantages/Disadvantages of propeller
Slipstream effect, more lift, more responsive rudder, quick response to power changes
Lack of speed due to prop RPM limits due to tips becoming supersonic
Why is a propeller blade twisted
To ensure a constant angle of attack throughout the blade
Why is the number 1 engine the critical engine on a multi engine propeller aircraft
SLIPSTREAM EFFECT
ASYMMETRIC BLADE EFFECT
What is SFC
Ratio of fuel burnt per hour to thrust produced in lbs
Advantages of the Fan Engine
Better SFC Reduced Noise Smaller engine Reduced contamination Larger airmass flow
Wide chord fan engines advantages
Better SFC, Reduced Weight, increased thrust, Less Noise
Pioneered by Rolls Royce
Why is an engine flat rated
The fan engine is flat rated to give it the widest possible range of operation, keeping within its defined structural limits, especially in dense air.
Why do Jet aircrafts operate as high as possible
Best SFC - as alt increases at constant Mach No. EAS decreases and therefore drag decreases, so thrust required decreases.
Due to decrease in density SFC reduces for optimal mixing of airflow
Engines operate at optimum efficiency at high 90-95% N1 - High RPM
Engine Hung Start Causes
High Altitude low density start
Hot temperature low density start
Inefficient compression - Damaged blades
Low starter RPMs
Engine Hot Start Causes
Tailwind Start
Over fueling combustion chamber
Blocked intake/exhaust
result of Hung, Wet start
Can a maximum takeoff weight aircraft use a reduced takeoff technique?
Yes, a reduced-thrust takeoff can be used even when an aircraft is at its maximum takeoff structural weight, providing the TOR/D is not limiting. This is so because you can trade momentum gained from a longer TOR/D to achieve the V1 and VR speeds at the performance-limiting conditions for a lower thrust setting
Why do you use variable/reduced thrust (flex) takeoffs in a jet aircraft?
Reduce Engine Noise, Increase engine life
Why does engine pressure ratio (EPR) need to be set by 40 to 80 knots on the takeoff role?
- So that the pilot is not chasing rpm needles on the takeoff roll.
- To ensure an adequate aircraft acceleration so that the performance-calculated V1 and VR speeds are achieved by the takeoff run required (TORR) rotate point for the given aircraft weight and ambient conditions.
6 main handling differences between Jet and Prop aircraft
Momentum Speed stability - Drag curve Swept wing - less lift Poor acceleration response at low rpm No Slipstream no Prop Drag
Measure change of latitude
1nm= 1 minute 60minutes = 1 degree
What is an INS
An INS is an onboard self-contained inertia navigation system that can provide continuous information on an aircraft’s position without any external assistance. An IRS (inertia reference system) is a modern INS that usually has a greater integration into the flight management system (FMS), and provides the aircraft’s actual magnetic position and heading information with reference to the FMS required position and heading. The directional acceleration information provided from the INS’s accelerometers and gyroscopes is calculated by the position computer that determines the aircraft’s present latitude and longitude position,
Components of INS
- Accelerometers 2. Gyroscopes 3. Position computer The aircraft moves in three dimensions, but the navigation equipment is only interested in acceleration in the horizontal plane. Therefore, the key to the whole INS arrangement is the accelerometers.
What are the disadvantages of an INS?
Bounded Errors - Errors than do not increase in time
Schuler Loop - Acceleration error, distance error
Incorrect alignment with true north - bounded velocity erros
Unbounded Errors - Errors that increase over time
Not make allowance that earth is not a perfect sphere
Initial position errors
True north error
System does not account for distance between to points at different heights
How does differential GPS work?
Global Positioning System (GPS) signals are received at a ground installation, which has been surveyed accurately. The ground installation then computes the differences between the known position and the position at which the GPS says it is (known as differential position error). It then sends a differential correction factor to any aircraft within 70 nautical miles using an aircraft communications and reporting system (ACARS) link that enables the aircraft’s onboard GPS navigation computer to correct its own normal GPS-derived position into a refined differential GPS position that is accurate to within 1 to 3 m. Therefore, differential GPS has the potential accuracy to be suitable for precision landing approaches,
Why is INS better than GPS
Only true self contained on board system, less prone to errors and external factors
What is FANS
Future Air Navigation Systems - All systems which improve air navigation. (GPS/INS ect ect)
What is R NAV
Area navigation - VOR/VOR DME/DME to plot track and position
Free Flight Concept
Operators can plot there own routing’s and pilots are responsible for air traffic avoidance by the use of TCAS, allows more direct routing
OMEGA FRQ
LORAN C FRQ
3-30 VLF
LF
How does a VOR work
FM reference-phase signal, which is omnidirectional, i.e., the same in all directions, and (2) an AM variable-phase signal, which has its phase varying at a constant rate, thus creating unique signals for each of the 360 radials. These VOR tracks or position lines are called radials;
VOR Errors
Propagation error - scalloping
Site Error
Equipment Error
How many inches of mercury to 1 HP
- 0295
33. 89
What happens to the indicated Mach number (MN) in a long-range cruise as weight decreases at the same flight level (FL)? It decreases.
DECREASES
ASI Errors
- Instrument error
- Pressure error
- Density error
- Compressibility error
- Maneuver error 6. Blocked pitot static system
Air Data Computer
Modern aircraft feed their static and pitot lines into an air data computer (ADC) that calculates the RAS, TAS, MN, TAT, ROC, and ROD and then passes the relevant information electronically to the servo-driven flight instruments
- Autopilot (AP)
- Flight director system (FDS)
- Flight management system (FMS)
- Ground proximity warning system (GPWS)
- Navigation aids
- Instrument comparison systems
What is TCAS
Traffic (Alert) Collision Avoidance System (TCAS) provides traffic information and maneuver advice between aircraft if their flight paths are conflicting with each other.
TCAS uses the aircraft’s secondary surveillance radar (SSR) transponders and is completely independent of any ground-based radar units.
TCAS I is an early system that provides traffic information only.
TCAS II is a later system that provides additional maneuver advice but in the main is restricted to vertical separation.
How Does TCAS work
An aircraft’s traffic collision avoidance system (TCAS) will interrogate the secondary surveillance radar (SSR) transponders of nearby aircraft to plot their positions and relative velocities.
RA’s should be restricted in the following circumstances
- In dense traffic area (limited to TA use)
- Descent recommendations inhibited below 1000 ft
- All RAs inhibited below 500 ft (Note: All TAs also restricted below 400 ft)
EGPWS
Terrain mapping - Predictive terrain closure
Probable windshear aural and visual warnings also can be generated to warn of an impending possibility of encountering windshear ahead.
Inputs GPWS
- Barometric altitude for rate of descent (ROD) calculations
- Radio altimeter
- Flap position
- Gear position
- Instrument landing system (ILS) glide slope
- Approach minima
- Throttle position
GPWS Warning system
Mode 1. Excessive barometric rate of descent
Mode 2. Terrain closure
Mode 3. Sinking flight path after takeoff or go-around Mode 4. Gear and flap not selected
Mode 5. Instrument landing system (ILS) glide slope deviation
Mode 6. Approach minimas
Windshear warning is sometimes classed as a GPWS mode because it uses the GPWS flight crew visual and aural warning system. However, strictly speaking, it is not a ground proximity warning but a separate system.
GPWS Mode priority
Highest - 1,2,3,4 - WHOOP WHOOP PULL UP
Lowest - 5
Descibe windshear warning system
Modern aircraft are provided with windshear warnings by using air data computer–detected changes in airspeed to calculate the presence of a windshear phenomenon, which it feeds to the ground proximity warning system (GPWS), which generates a “Windshear, windshear” aural and visual display on the main attitude directional indicator (ADI) flight instrument.
up to 1500ft AGL
A windshear warning requires an immediate go-around at full thrust and maximum flight director pitch-up attitude to avoid ground contact.
Order or Priority GPWS, Windshear, TCAS
- WIndshear
- GPWS
- TCAS
Describe FMS
Manages aircraft performance and navigation to achieve the most optimal flight possible
FMS 3 inputs
Pilot Inputs
Stored database
Information from aircraft systems
Tire Creep
Tyre turns around wheel eventually ripping out the valve and leading to a blow out
Tire temperature prior to takeoff depends on what factors?
- Outside air temperature
- Aircraft weight
- Taxi time
- Amount of braking
Brake temperature prior to takeoff depends on what factors
- Aircraft takeoff weight
- Pressure altitude
- Outside air temperature (OAT)
- Runway slope
- Tail/headwind
- Taxi times
What oxygen supply is delivered when selected to normal?
Why do you use 100% oxygen
Sea level oxygen pressure
It is not practical to keep the aircraft at the atmosphere’s sea-level pressure of 14.7 psi, but it is practical to increase the percentage volume of oxygen, thereby maintaining sea-level oxygen partial pressure.
BCF Fire extinguishers
Bromo-chlorodi-fluoro-methane
Jet/Propeller Screen height
50ft/35ft - Jet is lower due to the fact that the CL is lower on a swept wing jet aircraft
Weight effect V1
Field length limiting (ASDR) - V1 reduce
Field length unlimited - V1 Increase
V2 Speed
V2 (TOSS) speed is the takeoff safety speed achieved by the screen height in the event of an engine failure that maintains adequate directional control and climb performance properties of the aircraft.
V2= 1.1 x Vmca or 1.2 x Vs
Cruise Climb Profile
The cruise climb profile is a compromise between the best en route speed profile and the best climb profile—most commonly used by commercial traffic. It provides faster en route performance, a more comfortable aircraft attitude, better aircraft control due to lower angle of attack, and greater airflow over the control surfaces.
VRA/MRA
Turbulent air penetration speed
VDF/MDF
Max flight diving speed (certification trials)
Absolute Ceiling
The absolute ceiling is an aircraft’s maximum attainable altitude/flight level at which the Mach number buffet and prestall buffet occur coincidentally.
Service Ceiling
The maximum service ceiling is an aircraft’s’ imposed en route maximum operating altitude/flight level, which provides a safety margin below its absolute ceiling.
MRC
Maximum-range cruise. This is the speed at which, for a given weight and altitude, the maximum fuel mileage is obtained.
It is difficult to establish and maintain stable cruise conditions at maximum-range speeds.
LRC
This is a speed significantly higher than the maximum-range speed, i.e., 10 knots (M 0.01),this resuluts in a 1 percent mileage loss at a constant altitude. The long-range cruise schedule requires a gradual reduction in cruise speed as gross weight decreases with fuel burnoff.
Cost Index
A cost index (CI) is a performance management function that optimizes the aircraft’s speed for the minimum cost.
CI = CT/CF kg/min or 100 lb/hour
RATIO OF FLIGHT TIME/CONSUMPTION RATE TO FUEL COSTS
How is range increased flying into a headwind
Increase speed - Increase range due to reduced time - Increased SFC which is outweighed by time saving
LIGHT HEADWIND
Cruise Step Climb
A cruise (step) climb occurs when an aircraft in the cruise loses weight due to fuel burn, which allows the aircraft to fly higher; therefore, a cruise (step) climb is initiated to climb the aircraft to its new maximum altitude. Note: An aircraft
What is the Critical point in flight planning
Point of equal time along a route
What is RLW?
Restricted Landing Weight, i.e., the maximum landing weight for the runway length (LDA) and conditions.
Engine-out overshoot performance, weight, altitude, temperature (WAT), runway length (LDA), and runway condition.
What is latent heat
Latent heat is the heat energy, measured in calories, absorbed or released when water changes from one state to another.
DALR/SALR
Dry adiabatic lapse rate (DALR) is the adiabatic temperature change for unsaturated air as it rises. Unsaturated
Saturated adiabatic lapse rate (SALR) is the adiabatic change in temperature for saturated air as it rises.
Relative Humidity
and relative humidity is a measure of the amount of water vapor present in a parcel of air compared with the maximum amount it can support
Cloud definitions
- Cirro, or high-level cloud: (cloud base > 16,500–20,000 ft 2. Alto, or medium-level cloud: cloud base > 6500 ft
What is mist and fog
Mist and fog are simply parcels of low-level air in contact with the ground that have small suspended water droplets that have the effect of reducing visibility.
Describe upper winds
Upper winds are determined by the thermal gradient. A difference in temperature between two columns of air will cause a pressure difference at height even if both columns of air have the same sea level pressure. This pressure difference creates a wind (parallel to the isobars) at altitudethat is different from the wind experienced at sea level, even if no wind was present at sea level. The vector sum of the isotherm thermal wind component and the surface and upper isobar pressure-driven geostrophic (or gradient) wind produces the direction and speed of the upper wind. In the northern hemisphere, the thermal gradient is generally north-south (north cold and south warm), and therefore, the upper winds generally are westerly in direction (i.e., from the west), with the highest wind speed where the thermal gradient is greatest, e.g., jetstreams.
Where do you find Jetstreams
Jetstreams are driven by thermal gradients and therefore are found wherever the thermal gradient is high enough. There are two bands of rapid temperature changes (i.e., high/maximum thermal gradient) in each hemisphere that are marked enough to produce a jetstream. They are 1. At the polar front around 60 degrees of latitude, where the
polar air meets the subtropical air. This is a polar front jetstream, and is the most marked thermal gradient to be found, especially when it is over land in the winter. 2.
At the intertropical front, where the subtropical air meets the tropical air. This is known as the intertropical front jetstream.
Where is CAT most severe in a Jetstream
The maximum windshear/clear air turbulence (CAT) associated with a jetstream can be found level with or just above the jet core in the warm air but on the cold polar air side of the jet.
Windspeed with reduction in altitude
At the surface, the wind weakens in strength (speed) and backs in direction in the northern hemisphere (veers in direction in the southern hemisphere).
Cause of a Microburst
The microburst is a result of the downdrafts breaking out of the base of the cloud being colder than the surrounding air because it has only been warmed at the saturated adiabatic lapse rate (SALR) during the descent within the cloud. Therefore, since it is colder, it is also denser/heavier than the surrounding air, and thus it continues down to the surface, where it often can be felt as the first gust.
SIGMET
- Active thunderstorms
- Tropical revolving storms
- Severe line squalls
- Heavy rain
- Severe turbulence
- Severe airframe icing
- Marked mountain waves
- Widespread dust or sandstorms
What is the definition of RAPID in a forecast?
Less than 30minutes
What is an adequate/suitable aerodrome for ETOPS diversion
- Aircraft performance is suitable for the airfield
- Adequate emergency facilities are available at the aerodrome
- Adequate aerodrome lighting facilities are available for night flights
- A basic instrument approach is available for any expected instrument meteorologic conditions (IMC)
- The aerodrome is open
Typical Engine Fire drill
- Thrust lever close
- Auto throttle disengage
- Start lever switch off
- Engine fire warning switch engage
- Extinguish if necessary
ICAO Wake Turbulance Seperation
Heavy - Heavy - 4nm
Heavy - Medium - 5nm
Medium - Light - 5nm
Heavy - Light - 6nm
