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AIRCRAFT ENGINES AND SYSTEMS > CONFUSED > Flashcards

CONFUSED Flashcards

1
Q

Engine Pressure Ratio (EPR):

A

THRUST - T/O Ratio of turbine discharge to compressor inlet pressure used to measure thrust. The EPR gauge indicates the pressure ratio between the inlet and exhaust airflow. The EPR gauge is more widely used because it automatically accounts for some of the airflow variations at the inlet. With a Pt2 probe iced over, what indications will you get? A falsely high EPR The limiting factor of a gas turbine engine section is the turbine section On a cold day you are climbing out but not as well as expected. EPR gauge is not reading correctly. Cross check with RPM to ensure correct climb thrust is set.

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2
Q

EGT (Exhaust Gas Temperature):

A

EGT (Exhaust Gas Temperature): Measured aft of the turbine Why do we use EGT to determine engine performance?

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3
Q

TIT (Turbine Inlet Temperature):

A

Temperature of the gases from the combustion section of the engine as they enter the first stage of the turbine
TIT is the highest temperature inside a turbine engine and is difficult to measure which is why EGT is often measured instead

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4
Q

PRIMARY FOR PITCH IN STRAIGHT AND LEVEL FLIGHT IS
PRIMARY FOR BANK IS
PRIMARY FOR POWER IS

A

1 Altimeter.
2 HEADING INDICATOR
3 AIRSPEED INDICATOR

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5
Q

Define specific fuel consumption.

Fuel flow in gallons for a given airspeed.
Fuel flow in pounds for a given airspeed.
Fuel flow at a given cruise altitude.
Fuel flow in lbs. per hour at a given power setting.

A

Fuel flow in lbs. per hour at a given power setting.
Correct
Specific fuel consumption is the amount of fuel burned per hour per unit of thrust (lbs of fuel per hour/pounds of thrust). Reference: Aerodynamics for Naval Aviators, Turbojet Operating Characteristics
is the fuel efficiency of an engine design with respect to thrust output. TSFC may also be thought of as fuel consumption

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6
Q

LOAD METER

A

How do you tell the loads on the electrical bus? Check the load meter.Load meters will tell you to amperage load on a bus, usually in a fraction of the maximum load. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.

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7
Q

DRY RUNWAY ACCELERATE GO

For aircraft certification, what height must an aircraft be at the end of the runway with an engine failure at V1?

A

35 feet.
The first segment of climb FAR requirements requires that the aircraft be able to cross the departure end of the runway at 35 feet AGL. Reference: FAA Pilot Guide to Takeoff Safety.

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8
Q

CONTAMINATED RUNWAY. Engine out accelerate - go –

A

Go to 15-ft screen height

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9
Q

ANTI-SERVO TAB?

A

MOVES IN SAME DIRECTION AS THE PRIMARY CONTROL SURFACE IN ORDER TO INCREASE REQUIRED CONTROL FORCE PRESSURE. IT ALSO PREVENTS FULL DEFLECTION.
Provides feedback on the yoke to prevent over control.
An antiservo tab moves in the same direction, but to a greater degree, as the control surface. This makes moving the surface more difficult, adding control feel and making over control less likely. Reference: Pilot’s Handbook of Aeronautical Knowledge, Flight Controls.

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10
Q

SERVO TAB

A

Aileron-opposite direction REDUCES CONTROL FORCE.
Which device makes it possible to deflect large surfaces with relatively small control forces Servo Tabs.
Move the flight controls in the event of manual reversion.
A servo trim tab moves in the opposite direction as the aileron, thus helping the pilot deflect the control surface, making the airplane easier to maneuver (Figure 2-48). Servo trim tabs are typically found on ailerons.

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11
Q

CONTROL TABS

A

“MANUAL REVERSION” BACK UP TO FLIGHT CONTROLS THAT ARE NORMALLY OPERATE HYDRAULICALLY. MANUAL REVERSION UNLOCKS THE TABS ALLOWING THE PILOT TO OPERATE THE TABS BY MOVING THE CONTROL WHEEL AND THEREBY CAUSING THE FLT CONTROLS TO MOVE.

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12
Q

BATTERIES IN PARALLEL

A

Parallel, adds amperage but not voltage.
Correct
Batteries connected in parallel add amperage to a system, but voltage remains the same. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.

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13
Q

YOU HAVE 2 6 VOLT BATTERIES, HOW DO YOU MAKE 12 VOLTS?

A

Put the batteries in series.
Correct
Batteries placed in series will add voltage to a system in proportion to their total additive voltage. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.

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14
Q

Cruising along you have a total AC power failure. You are able to get one generator back online. How do you know how much power the generator is creating?

This is impossible. Both generators are necessary to power the aircraft.
A single generator can power the aircraft and the amperage will be the same as with all generators functioning.
Single generator would produce its rated EMF with double the amperage load upon it.
A single generator can power the aircraft and the amperage will be the same as with all generators functioning, but the batteries will discharge.

A

Single generator would produce its rated EMF with double the amperage load upon it.
Correct
One generator is sufficient to provide electrical power to the aircraft, but the load (amperage) will be doubled on that generator. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.

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15
Q

WHAT IS THE VOLTAGE AND FREQUENCY OF AN AIRCRAFT ELECTRICAL SYSTEM?

A

115 VAC, 400 Hz.
Correct
Most AC powered aircraft have a power rating of 115V at 400 Hz frequency. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.

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16
Q

If you lose air while starting a jet engine after ignition has occurred but before the completion of the start cycle, what is the most probable outcome?

Hot start.
No light start.
Failed compressor start.
Hung start.

A

HUNG START
A hung start occurs when there is inadequate compressor speed to continue the start process. The start will “hang” at a particular N1. A hot start may eventually result as fuel is ignited with insufficient air velocity through the combustion chamber. Reference: Airplane Flying Handbook, Transitioning to Jet Powered Airplanes.

17
Q

RAIM

A

Receiver autonomous integrity monitoring.
Correct
RAIM stands for receiver autonomous integrity monitoring. It is a receiver internal process that evaluates the performance of the GPS receiver. Reference: Pilot’s Handbook of Aeronautical Knowledge, Navigation.

18
Q

MODERN DAY AIRCRAFT BATTERY?

A

24 volts.
Correct
Modern aircraft batteries are rated at 24 Volts. Reference: Aviation Maintenance Technician Handbook – Airframe (Vol 2), Aircraft Electrical System.

19
Q

JET A FUEL WEIGHT PER GAL.

A

6.7 LBS PER GALLON

20
Q

DIFFERENTIAL SPOILERS

A

The term “differential spoilers” relates to how spoilers augment the roll commanded by the ailerons during speed brake operation. This arrangement maximizes the augmentation of roll control with a small sacrifice in (commanded) profile drag braking.

21
Q

NON DIFFERENTIAL SPOILERS

A

SPOILERS FULLY EXTENDED AS A SPEED BRAKE, BOTH SIDES REMAIN EXTENDED SPEED BRAKE POSITOTN SO THE SPOILERS DO NOT PROVIDE ROLL CONTROL
“Non-differential” spoiler arrangement will augment aileron roll control to a lesser degree during partial extension and when the speed brakes are fully extended, they offer no help.

22
Q

FIXED GEOMETRY, SPEED TATED JET ENGINE THE TOP 10% OF AVAILABLE ENGINE RMP (90-100%) REPRESENTS HOW MUCH MAX AVAIL THRUST?

A

30%

23
Q

LEVEL 310 .83 MACH ASKED TO SLOW TO MACH .80.

A

THE TURBINE POWER IS LESS THAN THE COMPRESSOR POWER REQUIRED TO MAINTAIN MACH .83

24
Q

WINGLETS

A

Winglets increase an aircraft’s operating efficiency by reducing what is called induced drag at the tips of the wings. An aircraft’s wing generates negative pressure on the upper surface and positive pressure on the lower surface as the aircraft moves forward.
Unequal pressure, however, also causes air at each wingtip to flow outward along the lower surface, around the tip, and inboard along the upper surface producing a whirlwind of air called a wingtip vortex. The effect of these vortices is increased drag and reduced lift that results in less flight efficiency and higher fuel costs.
Winglets, which are airfoils operating just like a sailboat tacking upwind, produce a forward thrust inside the circulation field of the vortices and reduce their strength. Weaker vortices mean less drag at the wingtips and lift is restored. Improved wing efficiency translates to more payload, reduced fuel consumption, and a longer cruising range that can allow an air carrier to expand routes and destinations.
To produce as much forward thrust as possible, the winglet’s airfoil is designed with the same attention as the airfoil of the wings themselves. Performance improvements generated by winglets, however, depend on factors such as the basic design of the aircraft, engine efficiency, and even the weather in which an aircraft is operating.

25
Q

Which hydraulic operation normally uses a double-acting, unbalanced linear actuator?

Brakes.
Landing gear.
Autopilot servo.
Rudder actuators.

A

Landing gear
Most piston-type actuating cylinders are double-acting, which means that fluid under pressure can be applied to either side of the piston to apply force and provide movement.

26
Q

Under normal operating conditions during flight, what is typically powering the electrical system of a large turbine aircraft?

A generator providing 115 volts, 400-Hz alternating current, powered through a ram air turbine.
A generator providing 115 volts, 400-Hz alternating current, powered through an engine’s constant speed drive unit.
A generator providing 115 KVA, 400-Hz alternating current, powered through an engine’s generator control unit.

A

A generator providing 115 volts, 400-Hz alternating current, powered through an engine’s constant speed drive unit.

27
Q

What increases or decreases the voltage of a generator so it carries its share of the load?

Current limiter
Rectifier.
Paralleling circuit.
Reverse current cut-out relay.

A

Paralleling circuit.

28
Q

The basic elements of the accessory section of a turbofan engine are:

The accessory case, which has machined mounting pads for the engine-driven accessories, and the gear train, which is housed within the accessory case.
The accessory gearbox, which has machined mounting pads for the engine-driven accessories, and the gear train, which is housed on the accessory case.
The engine starter, auxillary power unit, oil pump and filter, and the gear train, which is housed within the accessory case.
The engine starter, auxillary power unit, oil pump and filter, and the gear train, which is housed on the accessory case.

A

The accessory case, which has machined mounting pads for the engine-driven accessories, and the gear train, which is housed within the accessory case.

29
Q

WHEN CONSIDERING OBSTACLE CLEARANCE FOR ONE ENGINE INOPERATIVE TAKEOFF PERFORMANCE, WHICH OF THE FOLLOWING IS TRUE

PERFORMANCE IS PREDICATED ON CLEARING A 15 FOOT OBSTACLE WITH WET RUNWAY CONDITIONS
PERFORMANCE IS PREDICATED ON CLEARING A 35 FOOT OBSTACLE WITH WET RUNWAY CONDITIONS
PERFORMANCE IS PREDICATED ON CLEARING A 15 FOOT OBSTACLE WITH DRY RUNWAY CONDITIONS
PERFORMANCE IS PREDICATED ON CLEARING A 50 FOOT OBSTACLE WITH DRY RUNWAY CONDITIONS

A

PERFORMANCE IS PREDICATED ON CLEARING A 15 FOOT OBSTACLE WITH WET RUNWAY CONDITIONS

30
Q

Which are protective functions of an AC generator control unit?

Undervoltage, differential fault, and manual paralleling.
Generator underspeed and bus-tie circuit-breaker automatic closing.
Overvoltage, current limiting, and generator underspeed.
Overvoltage, current limiting, and generator overspeed.

A

Overvoltage, current limiting, and generator overspeed.

31
Q

For a typical fixed geometry, speed-rated jet engine, the top 10 percent of available engine rpm (i.e. 90%-100% N1) represents approximately how much of the maximum available thrust?

10%
20%.
30%.
40%.

A

30%.

32
Q

You are level at your cruise altitude of FL310 at a speed of Mach .83. ATC tells you to maintain a speed of no greater than Mach .80. You pull the thrust levers back and the engines decelerate. The engine are decelerated because:

The turbine power exceeds the compressor power required to maintain Mach .83.
The turbine power is less than the compressor power required to maintain Mach .83.
The power extracted by the turbine will equal the power required to operate the compressor.
The amount of ram air available to the compressor section diminishes.

A

The turbine power is less than the compressor power required to maintain Mach .83.

I WOULD GUESS THE OPPOSITE IS CORRECT IF YOU WERE ACCELERATING. THE COMPRESSOR POWER IS LESS THAN THE TURBINE POSER?????
I DON’T KNOW.

33
Q

Other modes of turbine ignition system operation:

Such as continuous ignition that is used at a higher voltage and energy level, are used for certain flight conditions
Such as generators that are used at a lower voltage and energy level, are used for certain flight conditions.
Such as generators that are used at a higher voltage and energy level, are used for certain flight conditions.

A

Such as continuous ignition that is used at a lower voltage and energy level, are used for certain flight conditions.

34
Q

WHEN SPOILERS ARE FULLY EXTENDED AS A SPEED BRAKE, BOTH SIDES REMAIN IN THE EXTENDED SPEED BRAKE POSITION, AND THEREFORE, THE SPOILERS DO NOT PROVIDE ANY ROLL CONTROL. WHAT TYPE OF SPOILER SYSTEM DOES THIS BEST DESCRIBE?

SEQUENTIAL
NON-SEQUENTIAL
DIFFERENTIAL
NON-DIFFERENTIAL

A

NON-DIFFERENTIAL
WITH DIFFERENTIAL THE SPOILERS FULLY EXTENDED THEY WOULD HELP WITH ROLL CONTROL.
WHEN THE NON-DIFFERENTIAL BRAKES ARE EXTENDED THEY DO NOT HELP WITH ROLL CONTROL, BUT THE DO HELP WITH ROLL CONTROL WHEN THEY ARE NOT EXTENDED.

35
Q

YOU ARE PREPARING FOR ENGINE START AT AN AIRPORT THAT HAS AN ALTITUDE OF 6400 FT MSL AND AN OUTSIDE AIR TEMPERATURE OF 32 CELSIUS. WHAT CONCERNS MIGHT YOU HAVE REGARDING ANY POSSIBLE START ANOMALIES?

THE HIGH DENSITY ALTITUDE MAY CONTRIBUTE TO A HUNG START
THE HIGH DENSITY ALTITUDE MAY CONTRIBUTE TO INADEQUATE FUEL VAPORIZATION LEADING TO A HOT START
AIR STARTER LIMITS MAY BE EXCEEDED
THE HIGH DENSITY ALTITUDE MAY CONTRIBUTE TO INADEQUATE IGNITION EFFECTIVENESS LEADING TO A HOT START

A

THE HIGH DENSITY ALTITUDE MAY CONTRIBUTE TO A HUNG START

36
Q

TRIM TABS

A

To lessen stick forces. It moves the OPPOSITE direction as the elevator.

AIRCRAFT ENGINES AND SYSTEMS (19 decks)

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