Ground Operation and Servicing

Question 1

8308. During starting of a turbine powerplant using a compressed air starter, a hung start occurred. Select the proper procedure.
      A— Shut off the fuel.
      B— Re-engage the starter.
      C— Shut the engine down.

Answer 1

C— Shut the engine down.

A hung start of a turbojet engine is a start in which the engine lights off as it should, but does not accelerate to a speed that allows it to operate without help from the starter. Anytime a hung start occurs, the engine should be shut down and the cause of the problem found and corrected.

Question 2

8309. A hung start in a jet engine is often caused by
      A— malfunctions in the ignition system.
      B— the starter cutting off too soon.
      C— an excessively rich fuel/air mixture.

Answer 2

B— the starter cutting off too soon.

A hung, or false, start is often the result of insufficient power to the starter or the starter cutting off before the engine reaches its self-accelerating speed.

Question 3

8310. Which statement below reflects a typical requirement when towing some aircraft?
      A— Discharge all hydraulic pressure to prevent accidental operation of the nosewheel steering mechanism.
      B— Tailwheel aircraft must be towed backwards.
      C— If the aircraft has a steerable nosewheel, the torque-link lock should be set to full swivel.

Answer 3

C— If the aircraft has a steerable nosewheel, the torque-link lock should be set to full swivel.

When towing a tricycle-gear airplane, the nose wheel torque-link lock should either be disconnected or set to full swivel, whichever the aircraft manufacturer recommends.
If this is not done, there is a good possibility that the tow bar can turn the nose wheel enough to break the steering stops.

Question 4

8311. Which statement is true regarding tiedown of small aircraft?
      A— The aircraft should be headed downwind in order to eliminate or minimize wing lift.
      B— Leave the nosewheel or tailwheel unlocked.
      C— Nylon or dacron rope is preferred to manila rope.

Answer 4

C— Nylon or dacron rope is preferred to manila rope.

Manila (hemp) rope has the tendency to shrink, not stretch, when it gets wet. Nylon and dacron rope are both superior to manila because they are stronger, and neither of them shrink when they are wet.
The airplanes should be pointed as nearly into the wind as practicable and the tail wheel or nosewheel should be locked in their straight-ahead position to prevent the wind slewing the aircraft around.

Question 5

8312. When approaching the front of an idling jet engine, the hazard area extends forward of the engine approximately
      A— 10 feet.
      B— 15 feet.
      C— 25 feet.

Answer 5

C— 25 feet.

It is extremely dangerous to approach an operating turbojet engine from either ahead or behind.
The hazard area extends out ahead of an idling turbojet engine for about 25 feet.

Question 6

8313. Which of the following is the most satisfactory extinguishing agent for use on a carburetor or intake fire?
      A— Dry chemical.
      B— A fine, water mist.
      C— Carbon dioxide.

Answer 6

C— Carbon dioxide.

Carbon dioxide (CO 2 ) is the most satisfactory fire-extinguishing agent to use for putting out an induction system f ire in an aircraft engine.
CO 2 does not damage the engine, and it does not leave any residue to clean up.

Question 7

8314. (Refer to Figure 50.) Identify the signal to engage rotor on a rotorcraft.
      A— 1.
      B— 3.
      C— 2.

Answer 7

B— 3.

Signal 3 means to engage the rotor.
Signal 1 means to start the engine.
Signal 2 means to stop the rotor.

Question 8

8315. If a radial engine has been shut down for more than 30 minutes, the propeller should be rotated through at least two revolutions to
      A— check for hydraulic lock.
      B— check for leaks.
      C— prime the engine.

Answer 8

A— check for hydraulic lock.

A radial engine that has been shut down for some time should be turned through by hand for at least two revolutions to check for a hydraulic lock.
A hydraulic lock is a condition in a reciprocating engine in which oil has leaked past the piston rings into a cylinder below the center of the engine.
If the engine fires when there is oil in any of its cylinders, it will sustain major structural damage.

Question 9

8316. The priming of a fuel injected horizontally opposed engine is accomplished by placing the fuel control lever in the
      A— IDLE-CUTOFF position.
      B— AUTO-RICH position.
      C— FULL-RICH position.

Answer 9

C— FULL-RICH position.

When starting a horizontally opposed aircraft engine equipped with a fuel-injection system, prime the engine by placing the mixture control in the FULL-RICH position and turning on the fuel boost pump until there is an indication of fuel flow on the flow meter.
After some fuel has flowed through the injector nozzles, the mixture control is returned to the IDLE-CUTOFF position and the engine is started.
As soon as the engine starts, the mixture control is again placed in the FULL-RICH position.

Question 10

8317. The most important condition to be monitored during start after fuel flow begins in a turbine engine is the
      A— EGT, TIT, or ITT.
      B— RPM.
      C— oil pressure.

Answer 10

A— EGT, TIT, or ITT

When starting a turbine engine, the most critical instrument to watch after the fuel flow begins is the EGT, TIT, or ITT to be sure that the engine lights off properly and the temperature does not rise above its allowable limits.

Question 11

8317-1.
Which of the following conditions has the most potential for causing engine damage when starting or attempting to start a turbine engine?
A— Hung start.
B— Cold start.
C— Hot start.

Answer 11

C— Hot start.

A hot start is one in which the EGT or TIT rises above its allowable limit. An engine can be seriously damaged by a hot start.

Question 12

8318. How is a flooded engine, equipped with a float-type carburetor, cleared of excessive fuel?
      A— Crank the engine with the starter or by hand, with the mixture control in cutoff, ignition switch off, and the throttle fully open, until the fuel charge has been cleared.
      B— Turn off the fuel and the ignition. Discontinue the starting attempt until the excess fuel has cleared.
      C— Crank the engine with the starter or by hand, with the mixture control in cutoff, ignition switch on, and the throttle fully open, until the excess fuel has cleared or until the engine starts.

Answer 12

A— Crank the engine with the starter or by hand, with the mixture control in cutoff, ignition switch off, and the throttle fully open, until the fuel charge has been cleared.

A flooded reciprocating engine can be cleared of excessive fuel by placing the mixture control in the CUTOFF position to shut off all flow of fuel to the cylinders. Turn the ignition off, open the throttle and crank the engine with the starter or by hand until the fuel charge in the cylinders has been cleared.

Question 13

8319. (Refer to Figure 51.) Which marshalling signal should be given if a taxiing aircraft is in imminent danger of striking an object?
      A— 1 or 3.
      B— 2.
      C— 3.

Answer 13

C— 3.

Signal 3 calls for an emergency stop.
If the aircraft is in imminent danger of striking an object, the signal shown in 3 should be used.
Signal 1 means to stop.
Signal 2 means to come ahead.

Question 14

8320. Generally, when an induction fire occurs during starting of a reciprocating engine, the first course of action should be to
      A— discharge carbon dioxide from a fire extinguisher into the air intake of the engine.
      B— continue cranking and start the engine if possible.
      C— close the throttle.

Answer 14

B— continue cranking and start the engine if possible.

If an induction system fire occurs when starting a reciprocating engine, the best procedure is to continue cranking and start the engine if possible. When the engine starts, the air flowing into the engine will extinguish the fire.

Question 15

8320-1.
If a fire develops in an engine during the starting procedure, you should
A— discontinue the start attempt and allow the fireguard to extinguish the fire.
B— continue cranking to start the engine and extinguish the fire.
C— continue cranking and allow the fireguard to extinguish the fire.

Answer 15

B— continue cranking to start the engine and extinguish the fire.

If an engine fire develops during the starting procedure, continue cranking to start the engine and blow out the f ire. If the engine does not start and the fire continues to burn, discontinue the start attempt. The fireguard should extinguish the fire using the available equipment.

Question 16

8321. When starting and ground operating an aircraft’s engine, the aircraft should be positioned to head into the wind primarily
      A— to aid in achieving and maintaining the proper air f low into the engine induction system.
      B— for engine cooling purposes.
      C— to help cancel out engine torque effect.

Answer 16

B— for engine cooling purposes.

Position the aircraft to head into the prevailing wind to ensure adequate air flow over the engine for cooling purposes.

Question 17

8322. When approaching the rear of an idling turbojet or turbofan engine, the hazard area extends aft of the engine approximately
      A— 200 feet.
      B— 100 feet.
      C— 50 feet.

Answer 17

B— 100 feet.

The hazard area extends aft of an idling turbojet or turbofan engine for approximately 100 feet.

Question 18

8323. If a hot start occurs during starting of a turbine powerplant, what is the likely cause?
      A— The starting unit overheated.
      B— The ambient air temperature was too high (over 100°F).
      C— The fuel/air mixture was excessively rich.

Answer 18

C— The fuel/air mixture was excessively rich.

A hot start of a turbojet engine is one in which the engine starts normally but the exhaust-gas temperature exceeds its allowable limits. Hot starts are usually caused by too rich a fuel/air mixture. (There was too much fuel for the amount of air being moved through the engine by the compressor.)

Question 19

8324. What effect, if any, will aviation gasoline mixed with jet fuel have on a turbine engine?
      A— No appreciable effect.
      B— The tetraethyl lead in the gasoline forms deposits on the turbine blades.
      C— The tetraethyl lead in the gasoline forms deposits on the compressor blades.

Answer 19

B— The tetraethyl lead in the gasoline forms deposits on the turbine blades.

Many aviation gas turbine engine manufacturers allow the use of some aviation gasoline as a fuel when turbine fuel is not available.
The manufacturer limits the amount of time aviation gasoline can be used for two reasons: (1) The tetraethyl lead in the aviation gasoline causes deposits to form on the turbine blades. (2) Aviation gasoline does not have the lubricating properties of kerosine. Using too much gasoline can cause excessive wear on the fuel control.

Question 20

8325.

(1) Jet fuel is of higher viscosity than aviation gasoline and therefore holds contaminants more readily.

(2) Viscosity has no relation to contamination of fuel.

Regarding the above statements,
A— only 1 is true.
B— both 1 and 2 are true.
C— neither 1 nor 2 is true.

Answer 20

A— only 1 is true.

Statement 1 is true. Jet fuel has a higher viscosity than gasoline and it holds contaminants more readily (better) than gasoline.
Statement 2 is not true. Viscosity does have a great deal to do with the fact that jet fuel holds more contaminants than gasoline. The higher the viscosity, the fewer contaminants will settle out of the fuel.

Question 21

8326. When towing a large aircraft
      A— a person should be in the cockpit to watch for obstructions.
      B— persons should be stationed at the nose, each wingtip, and the empennage at all times.
      C— a person should be in the cockpit to operate the brakes.

Answer 21

C— a person should be in the cockpit to operate the brakes.

When a large aircraft is being towed, there should be a person in the cockpit to operate the brakes in the event of an emergency.

Question 22

8327. Weathervaning tendency is greatest when taxiing
      A— both nosewheel and tailwheel-type airplanes in a quartering tailwind.
      B— a tailwheel-type airplane in a direct crosswind.
      C— a nosewheel-type airplane in a quartering headwind.

Answer 22

B— a tailwheel-type airplane in a direct crosswind.

Weathervaning tendency is more prevalent in the tailwheel-type because the airplane’s surface area behind the main landing gear is greater than in nosewheel-type airplanes. The tendency of a tailwheel-type airplane to weather vane is greatest while taxiing directly crosswind. It is difficult to prevent the airplane from turning into any wind of considerable velocity since the airplane’s rudder capability may be inadequate to counteract the crosswind.

Question 23

8328. When taxiing an airplane with a quartering tailwind, the elevators and
      A— upwind aileron should be held in the up position.
      B— upwind aileron should be held in the down position.
      C— both ailerons should be kept in the neutral position.

Answer 23

B— upwind aileron should be held in the down position.

When taxiing with a quartering tailwind, the elevator should be held in the DOWN position, and the upwind aileron, DOWN. Since the wind is striking the airplane from behind, these control positions reduce the tendency of the wind to get under the tail and the wing and to nose the airplane over.

Question 24

8329. When taxiing (or towing) an aircraft, a flashing red light from the control tower means
      A— stop and wait for a green light.
      B— move clear of the runway/taxiway immediately.
      C— return to starting point.

Answer 24

B— move clear of the runway/taxiway immediately.

The meanings of the light signals that are used by control towers to control the operation of aircraft on the ground are:
Flashing red—Taxi clear of the runway or taxiway Steady red—Stop
Steady green—OK to taxi
Alternating red and green—OK to taxi, but exercise extreme caution
Flashing white—Return to starting point

Question 25

8330. A person should approach or leave a helicopter in the pilot’s field of vision whenever the engine is running in order to avoid
      A— the tail rotor.
      B— the main rotor.
      C— blowing dust or debris caused by rotor downwash.

Answer 25

A— the tail rotor.

When approaching or leaving a helicopter whose engine is running, you should remain within the pilot’s field of vision to avoid an encounter with the tail rotor.

Question 26

8331. When taxiing (or towing) an aircraft, a flashing white light from the control tower means
      A— move clear of the runway/taxiway immediately.
      B— OK to proceed but use extreme caution.
      C— return to starting point.

Answer 26

C— return to starting point.

The meanings of the light signals that are used by control towers to control the operation of aircraft on the ground are:
Steady red—Stop
Flashing red—Taxi clear of the runway or taxiway
Steady green—OK to taxi
Alternating red and green—OK to taxi, but exercise extreme caution
Flashing white—Return to starting point

Question 27

8332. When taxiing (or towing) an aircraft, an alternating red and green light from the control tower means
      A— move clear of the runway/taxiway immediately.
      B— OK to proceed but use extreme caution.
      C— return to starting point.

Answer 27

B— OK to proceed but use extreme caution.

The meanings of the light signals that are used by control towers to control the operation of aircraft on the ground are:
Steady red—Stop
Flashing red—Taxi clear of the runway or taxiway
Steady green—OK to taxi
Alternating red and green—OK to taxi, but exercise extreme caution
Flashing white—Return to starting point

Question 28

8333. When stopping a nosewheel-type airplane after taxiing, the nosewheel should be left
      A— unlocked and pointed straight ahead.
      B— turned at a small angle towards uphill if the parking area is not perfectly flat.
      C— pointed straight ahead.

Answer 28

C— pointed straight ahead.

When stopping an airplane that is equipped with a nosewheel, the nosewheel should be left straight ahead to relieve any strain on the nose gear and to make it easier to start moving straight ahead.

Question 29

8334. When first starting to move an aircraft while taxiing, it is important to
      A— test the brakes.
      B— closely monitor the instruments.
      C— notify the control tower.

Answer 29

A— test the brakes.

When first starting to taxi an airplane, test the brakes for proper operation. If braking action is unsatisfactory, the engine should be shut down immediately.

Question 30

8335. The color of 100LL fuel is
      A— blue.
      B— colorless or straw.
      C— red.

Answer 30

A— blue.

Low-lead 100-octane aviation gasoline is dyed blue. Turbine fuel is normally colorless or straw colored. Grade 80 aviation gasoline is dyed red.

Question 31

8336. How are aviation fuels, which possess greater antiknock qualities than 100 octane, classified?
      A— According to the milliliters of lead.
      B— By reference to normal heptane.
      C— By performance numbers.

Answer 31

C— By performance numbers.

Aviation fuel whose antidetonation characteristics are better than those of the reference fuel (100-octane) are rated in performance numbers.

Question 32

8337. Why is ethylene dibromide added to aviation gasoline? A— To remove zinc silicate deposits from the spark plugs.
      B— To scavenge lead oxide from the cylinder combustion chambers.
      C— To increase the antiknock rating of the fuel.

Answer 32

B— To scavenge lead oxide from the cylinder combustion chambers.

Tetraethyl lead is added to aviation gasoline to improve its antidetonation characteristics (to raise its critical pressure and temperature), but deposits left inside the cylinders from the tetraethyl lead foul spark plugs and cause corrosion. In order to get rid of the residue from the tetraethyl lead, ethylene dibromide is mixed with the gasoline.
When the gasoline burns, the ethylene dibromide combines with the lead and forms volatile lead bromides that go out the exhaust and do not form solid contaminants inside the cylinder.

Question 33

8338. Both gasoline and kerosene have certain advantages for use as turbine fuel. Which statement is true in reference to the advantages of each?
      A— Kerosene has a higher heat energy/value per unit weight than gasoline.
      B— Gasoline has a higher heat energy/value per unit volume than kerosene.
      C— Kerosene has a higher heat energy/value per unit volume than gasoline.

Answer 33

C— Kerosene has a higher heat energy/value per unit volume than gasoline.

Gasoline has a higher heat energy per pound than kerosine (nominally 20,000 Btu per pound for gasoline versus about 18,500 Btu per pound for kerosine).
Kerosine, however, weighs more than gasoline (about 6.7 pounds per gallon for kerosine compared with about 6.0 pounds per gallon for gasoline).
Because there are more pounds of kerosine per gallon, there are more Btu’s in a gallon of kerosine than in a gallon of gasoline.

Question 34

8339. What must accompany fuel vaporization?
      A— An absorption of heat.
      B— A decrease in vapor pressure.
      C— A reduction in volume.

Answer 34

A— An absorption of heat.

When fuel changes from a liquid into a vapor, it absorbs heat from the surrounding air. This absorption of heat drops the temperature of the air enough that moisture can condense out and freeze. This is the main cause of carburetor ice.

Question 35

8340. Characteristics of detonation are
      A— cylinder pressure remains the same, excessive cylinder head temperature, and a decrease in engine power.
      B— rapid rise in cylinder pressure, excessive cylinder head temperature, and a decrease in engine power.
      C— rapid rise in cylinder pressure, cylinder head temperature normal, and a decrease in engine power.

Answer 35

B— rapid rise in cylinder pressure, excessive cylinder head temperature, and a decrease in engine power.

Detonation is an uncontrolled burning, or explosion, of the fuel/air mixture within the cylinder of a reciprocating engine.
The fuel/air mixture ignites and burns normally. But as it burns, it compresses and heats the mixture ahead of the f lame front. When the heated and compressed mixture reaches its critical pressure and temperature, it releases its energy almost instantaneously (it explodes).
It is the explosions inside the cylinder that cause the cylinder-head temperature to go up, the cylinder pressure to go up, and the engine power to decrease.

Question 36

8341. A fuel that vaporizes too readily may cause
      A— hard starting.
      B— detonation.
      C— vapor lock.

Answer 36

C— vapor lock.

If a fuel vaporizes too readily, it has a high vapor pressure. It requires a high pressure to keep the vapors in the fuel.
Vapors that form in a fuel line can prevent liquid fuel f lowing through the line and can stop the engine because of fuel exhaustion. This is a vapor lock.

Question 37

8342. Jet fuel number identifiers are
      A— performance numbers to designate the volatility of the fuel.
      B— performance numbers and are relative to the fuel’s performance in the aircraft engine.
      C— type numbers and have no relation to the fuel’s performance in the aircraft engine.

Answer 37

C— type numbers and have no relation to the fuel’s performance in the aircraft engine.

Jet engine fuel identification numbers (JP-4, JP-5, Jet A, Jet A1, and Jet B) are identification numbers only and do not relate in any way to the performance of the fuel in the engine.

Question 38

8343. The main differences between grades 100 and 100LL fuel are
      A— volatility and lead content.
      B— volatility, lead content, and color.
      C— lead content and color.

Answer 38

C— lead content and color.

The main difference between grades 100 and 100LL aviation gasoline is the content of tetraethyl lead and the color. Their antiknock characteristics are the same.
Grade 100 is allowed to have a maximum of 3.0 milliliter of TEL per gallon, and it is dyed green.
Grade 100LL is allowed to have a maximum of 2.0 milliliter of TEL per gallon, and it is dyed blue.

Question 39

8344. Characteristics of aviation gasoline are
      A— high heat value, high volatility.
      B— high heat value, low volatility.
      C— low heat value, low volatility.

Answer 39

A— high heat value, high volatility.

Aviation gasoline is suitable as a fuel for reciprocating engines because it has a high heat value (nominally 20,000 Btu per pound) and a high volatility. It readily changes from a liquid into a vapor so that it can be burned.

Question 40

8345. Tetraethyl lead is added to aviation gasoline to
      A— retard the formation of corrosives.
      B— improve the gasoline’s performance in the engine. C— dissolve the moisture in the gasoline.

Answer 40

B— improve the gasoline’s performance in the engine.

Tetraethyl lead is added to aviation gasoline to increase its critical pressure and temperature.
The higher critical pressure and temperature allow the engine to operate with higher cylinder pressures without the fuel/air mixture detonating.

Question 41

8346. A fuel that does not vaporize readily enough can cause A— vapor lock.
      B— detonation.
      C— hard starting.

Answer 41

C— hard starting.

An ideal fuel for an aircraft reciprocating engine must vaporize (change from a liquid into a vapor) easily, yet it must not vaporize so easily that it will form vapor locks in the fuel system.
Liquid fuel will not burn, so for it to burn, it must be changed into a fuel vapor. If the fuel does not vaporize readily enough, it will cause the engine to be hard to start.