Flight Ops Flashcards
One of the main advantages of the axial flow compressor type of gas turbine as compared to the centrifugal type:
Comparatively small frontal area of the compressor
Section of a turbine engine which extracts energy from expanding high velocity combustion gases to drive the compressor sections and fan (or prop) is the:
Turbine section
Component of a gas turbine engine which is located at the outlet side of a centrifugal compressor and whose function is to convert high velocity airflow into high pressure airflow for delivery to the combustion section is:
Diffuser section
Majority of the energy produced in the burner section of a turbojet engine is used for?
Running the engine compressor. Up to 75% of energy
In a turbo fan engine, why is bypassed air more efficient at creating engine thrust?
Cooler bypassed air is more dense than hot exhaust air, therefore containing more energy
N1 and N2 gauges indicate what?
Rotation rate of the Low and high pressure compressors respectively, expressed as a percentage
When starting a gas turbine engine the two primary gauges to observe are:
High pressure compressor and internal turbine temperature
What provides the rotational energy for an axial flow compressor in a turbojet engine?
The engine turbine using energy from hot exhaust gases exiting the engines burner section
What occurs in the burner section of a gas turbine?
Fuel is mixed with compressed air then ignited to create the energy needed to run the engine.
EPR is correctly defined as:
The ratio of turbine discharge total pressure to the total pressure at the compressor inlet.
The stationary blade type airfoil devices that are installed between each compressor stage in order to direct airflow into succeeding stages at optimum angle in the axial flow compressor are:
Stators
When air is extracted from the compressor section for service functions such as air conditioning or anti icing then:
Thrust will decrease and turbine temperature will increase
T/F - On cascade type reversers, blocker doors seal off the fan exit as a sleeve moves to expose the cascade vanes.
True
A turboprop power plant design known as ‘free turbine’ is one in which:
There are two separate shafts - one to drive the compressor and the other to transmit power to the reduction gearbox and thus turn the prop
In reference to a turbo prop, constant speed is achieved by:
Matching the prop load to the gas turbine power produced
The flex temperature for a gas turbine engine refers to:
The assumed temperature used in calculating the reduced thrust settings for take off
What is the purpose of assumed temperature or de-rated take offs?
They reduce engine wear
With respect to the px system, what is the purpose of a negative px relief valve?
To prevent outside ambient air pressure from exceeding cabin internal pressure
An aircraft’s electrical bus bar system can best be described as:
Carefully organized bunch of separate but interconnected circuits which allow important circuits to be isolated and powered by alternate sources in the event of component failure
Aircraft electrical circuit protection is provided by:
- Generator control unit
- Circuit breaker
Jet pumps are activated by:
High px fuel from the high px fuel pump
Magnasticks are fuel quantity measuring devices which:
Are located beneath the wings and allow for manual measuring of fuel quantity
One method to compensate for variable system demands when one or more subsystems are activated on a hydraulic system is through the installation of:
Variable displacement hydraulic pumps
T/F - Touchdown protection prevents inadvertent brake application prior to wheel spin up on low friction runways
True
Induced drag is:
Inversely proportional to the square of the speed.
When operating in slow flight, the req power is greater then that for endurance because:
The Lift/Drag Ratio is reduced, and the drag increased
In order to obtain max range in a constant wind condition, a pilot flying a turbojet aircraft at near optimum altitude and at the recommended airspeed should:
Reduce power and indicated airspeed as fuel weight decreases
T/F - wing dihedral improves lateral stability of an A/C
True
If the CoG is at the most aft limit, what would be the effect on the stability of the AC?
Decreased longitudinal stability about the lateral axis
An AC has greater longitudinal stability when:
The CoG is well forward of the centre of pressure
Why is having a moving horizontal stabilizer a more effective way of trimming large aircraft?
It allows for a greater centre of gravity range and reduces drag in flight
An aircraft in a constant descent, weight will equal:
Vertical component of lift and drag
Wing tip vortices of minimum strength would be developed by an aircraft:
Flying at high speeds, long wing span, and clean config
Wing tip vortices of maximum strength are generated by aircraft operating under conditions of:
High gross weight, clean, low speeds
The speed of sound in the atmosphere is solely dependent upon:
Air temperature
What range of Mach does the transonic flight regime occur?
0.75 - 1.20M
The type of airflow normally present within transonic regime of flight is:
Subsonic and supersonic
Critical Mach number may be defined as:
Highest airspeed at which the airflow over any part of the aircraft first reaches (but does not exceed) Mach 1.0
Limiting Mach number may be defined as:
The maximum operating speed of an aircraft in relation to the speed of sound
In high speed aircraft, sweepback design is utilized to:
Increase critical Mach number
An undesirable effect of sweepback design in a jet aircraft is:
Dutch roll tendency
How is high and low speed buffet (coffins corner) affected in a level turn?
Low speed buffet increases and high speed buffet decreases
What factors should be considered in preventing the onset of Mach buffet?
- Aircraft weight
- Temperature
- Upper level winds
- Altitude
Wing vortex generators are employed for:
Delaying boundary layer separation
What is the purpose of leading edge flaps?
Increase coefficient of lift by changing the camber of wing
Slotted trailing edge flaps have what advantage over plain flaps?
The slot helps postpone boundary layer separation creating more lift at high flap settings
T/F - winglets reduce induced drag but do cause some increase in form drag
True
One of the main advantages of canard design is:
A reduced stall speeds
A small executive jet aircraft has a main wheel pressure of 135psi and a nosewheel pressure of 45 psi, what speeds will the tires hydroplane?
The nosewheel will hydroplane at lower speeds then the mains
When a constant headwind component shears to a calm wind, the initial cockpit indications to a pilot would be:
Aircraft pitches down, altitude and indicated airspeed decrease
Blockage of static air. If the plane departs altitude the airspeed indicator would:
Under-read during a climb, and over-read during a descent
What always happens in an aerodynamic stall?
- Buffeting
- Lots of aerodynamic noise
- The aircraft will always descend
Minimum PAPI approach slope indicator system safe obstruction clearance area dimensions
6 degrees on either side of the extended runway centreline out to 4nm from the threshild
The ‘clean aircraft concept’ refers to:
Take off being prohibited when frost, snow. Or ice is adhering to any critical surface of the aircraft
Frost, ice or snow having thickness and surface roughness of medium/coarse sand paper on the leading edge and upper surface of a wing can:
Decrease lift by 30% and increase drag by 40%
What is required when type II or IV is applied to the aircraft?
The rotation speed must be 100kts or greater
T/F - planning to fly approaches with maximum flap settings can minimize the chance of having a tail plane stall occurrence
False
Type I with higher concentration of glycol will provide:
Some protection against re-freezing but not much against further accumulation
Mach number equation
TAS/LSS
Hydroplaning is a function of:
The speed of the airplane, tire pressure and water depth
When would PAPIs be turned off?
On a precision app when ceiling less then 500’ or vis less then 1 mile
VASIS variations
V1 - 2 bar, EWH up to 10ft
V2 - 2 bar, EWH up to 25ft
AV - abbreviated, EWH up to 10ft
PAPI variations
P1 - EWH up to but not including 10ft
P2 - EWH 10ft up to, not including 25ft
P3 - 25 up to not including 45ft
AP - abbreviated up to not including 10ft
Viscous vs dynamic hydroplaning vs reverted rubber
Viscous - thin film of water, low tire speeds
Dynamic - deeper water, results in complete loss of tire contact. Tire rides on wedge of water
Reverted rubber - generally following a mechanical failure, resulting heat generates steam in contact area which provides upward motion/px on tire
3 types of reversers, and type of air used
Cascade - cold bypass air reversed
Blocker/target - cold bypass
Bucket/target - hot air 100%
The autopilot controls the aircraft around and about the:
Centre of gravity
Coffins corner definition
Stall speed in Mach could equal or come close to MMO, so the pilot could not slow down (without stalling) or speed up (without exceeding MMO)
EWH is:
Vertical distance from pilots eyes to lowest portion of the aircraft (in ldg config) at Vref
If a small airplane is using P3 system, where would it land?
Long
Icing is anticipated when OAT on ground or TAT in flight is ___° or below and visible moisture is present
10
T/F - when the anti-skid control module detects that the wheel speed transducer velocity is lower than the reference speed velocity, a brake release signal is commanded.
True
How does dihedral improve lateral stability?
When one wing drops due to a disturbance, the unbalanced force produces a side slip towards the dropped wing. This cause the wind to hit the downward wing at a higher angle of attack producing more lift then the upward wing and bring the aircraft back to level
Hydroplaning equations (non rotating/rotating tire)
Non rotating = 7.7 x (square root of tire px)
Rotating tire = 9 x (square root of tire px)
Stall speed of aircraft executing a banked turn - equation
Normal stall speed x (square of the load factor)
60° - 2g
45° - 1.4g
TAS equation
IAS x [1 + (alt/1000 x .02)]
What is the best way to remove smoke from the cabin?
Climb the pressure altitude
What does a fixed displacement pump do?
It has a set flow rate, every stroke of the motor moves the same amount of fluid. System requires shock absorbing pressure accumulator.
What does a variable displacement pump do?
Varys volume of fluid, no accumulator required, however if there is one, the accumulator stores energy.
What is crossover protection with anti-skid?
Allows wheels to talk to each other. If one wheel hits ice but the other doesn’t, it keeps both wheels in the same state. Also helps if a sensor fail.
2 types of fire detection
Spot detection
-thermal switch: two metals expand and contact lighting switch
-thermocouple: temperature based
Loop detection
-single element Fenway/kedde: detects drop in resistance of electrical current
What is at the bottom of the total drag curve?
Max endurance
What does critical engine mean?
It creates the greatest amount of yaw upon failing which in turn requires the most rudder in an engine out situation
How does density altitude affect a turbocharged engine?
Negatively. Performance degrades as it does not overcome decreased prop efficiency, increased TAS
What is the low landing regime?
Landing config, low airspeed, low power, low altitude.
T/F - aircraft are certified to successfully complete a go around with ground contact once it has entered the low energy landing regime.
True
What happens when air passes through a shockwave?
-pressure, temperature, density increase
-velocity decrease
How many miles are VASIS’s accurate?
4-6 miles
How are PAPI’s determined for an aerodrome?
By the type of aircraft the aerodrome intends to serve
Visible moisture is:
-vis is <1nm
-taxiways/runways contaminated by slush/snow/water
-precip
-cloud
Tail plane stall symptoms and recovery
-buffeting, sluggish elevator, unusual nose down trim changes
-retraction of flaps to previous setting and increase airspeed for app
How can you tell between a spin and a spiral dive looking at a picture of two EFIS screens?
Airspeed. Spin is a stall, spiral dive is increasing airspeed
Spiral dive recovery
Idle
Level wings
Ease out of dive
Spin recovery
-Full rudder opposite of direction of spin
-forward on the stick to break stall
During walk around, the right aileron trim is up and rudder trim is right. What cockpit indications would this show?
Left aileron, left rudder
If you encounter any of these compressibility effects, what should you do?
Uncontrollable roll, aileron ‘buzz’, wing twist, buffeting
Reduce speed
What will happen as you pass critical Mach number?
A strong nose down tendency will start to occur
What happens to TAS/IAS if you climb at a constant Mach number?
Both decrease
What happens to Mach/IAS if you were to descend at a constant TAS?
Mach decreases, IAS increases
Frost formation definition
Frost initially forms as individual grains about 0.004 of an inch in diameter.
Wing tip vortices increase what kind of drag?
Induced
