# Jet Mechanics Qui: Auxiliary Power Unit Test

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What do you think about jet mechanics? A jet mechanic completes maintenance on airplanes that are supplied with gasoline turbine jet engines. This quiz touches upon how to start an APU without external power, how long an ATM can operate without normal hydraulic pressure, what amount of fuel is necessary for operating PTU’s, which EGT reading would indicate malfunction, and what APU is the maximum start time. Get your motor running with this quiz on Jet Mechanics.

• 1.

### When starting an APU without external power (BATTERY START) what equipment must be available?

• A.

A fire guard with a portable fire extiguisher.

• B.

A fire guard with a two-way radio.

• C.

A fire truck shall stand by until power is available.

• D.

A fire truck shall stand by during starting and single APU operation.

D. A fire truck shall stand by during starting and single APU operation.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-1, WARNING

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• 2.

### For cooling purposes, the APU should be run unloaded for _________ prior to shut down?

• A.

30 seconds

• B.

1 minute

• C.

2 minutes

• D.

3 minutes

C. 2 minutes
Explanation
The APU should be run unloaded for 2 minutes prior to shut down for cooling purposes. Running the APU without any load allows the internal components to cool down before shutting off, preventing any potential damage or overheating. This cooling period ensures that the APU is properly cooled and ready for the next operation.

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• 3.

### How long can an ATM operate without normal hydraulic pressure?

• A.

5 seconds

• B.

15 seconds

• C.

30 seconds

• D.

60 seconds

B. 15 seconds
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 5-4, CAUTION

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• 4.

### To operate the ATM's, PTU's or the engine pumps, the number two and three main fuel tanks must have a minimum of ________ of fuel to provide case drain fluid cooling for the hydraulic systems.

• A.

2000 lbs

• B.

4500 lbs

• C.

4000 gal

• D.

2000 gal

B. 4500 lbs
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-7, STEP 15

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• 5.

### During APU start, what is the maximum duration for transient EGT between 715 degrees C and 824 degrees C?

• A.

10 seconds

• B.

20 seconds

• C.

30 seconds

• D.

No limit

B. 20 seconds
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-3, ITEM 3.A.(2)

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• 6.

### Why must one battery be serviceable and connected to the battery bus during operation of the APU?

• A.

To provide emergency power for radio operation.

• B.

To provide power for APU fire extiguisher and emergency APU shut down.

• C.

To provide power for APU fire extiguisher and emergency radio operation.

• D.

To provide emergency radio operation and power for emergency APU shut down.

B. To provide power for APU fire extiguisher and emergency APU shut down.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-6.3, WARNING

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• 7.

### During APU start, which of the following EGT readings would indicate a malfuction?

• A.

630-691 degrees C

• B.

691-715 degrees C

• C.

716-824 degrees C

• D.

325-575 degrees C

C. 716-824 degrees C
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-3 - 4-4 ITEM 3.A (1)

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• 8.

### Where are the APU fire extinguisher bottles located on the aircraft?

• A.

In the lower aft corner of the #4 main landing gear wheel well.

• B.

In the lower aft corner of the #2 main landing gear wheel well.

• C.

Inboard side of #2 and #3 engine pylons.

• D.

In the right aft APU compartment.

A. In the lower aft corner of the #4 main landing gear wheel well.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 10-2, PARA 10-3

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• 9.

### Normal ATM pumps pressure is__________?

• A.

2800-3000 psi

• B.

2850-3150 psi

• C.

2850-3050 csi

• D.

2800-3150 psi

B. 2850-3150 psi
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 5-5, step 8

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• 10.

### Which hydraulic systems are used to pressurize the APU accumulators?

• A.

Left APU accumulator from #4 system and right APU accumulator from #1 system.

• B.

Left APU accumulator from #2 system and right APU accumulator from #3 system.

• C.

Left APU accumulator from #1 system and right APU accumulator from #4 system.

• D.

Left APU accumulator from #3 system and right APU accumulator from #2 system.

C. Left APU accumulator from #1 system and right APU accumulator from #4 system.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 5-5, step 8a

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• 11.

### What is to be done if the battery voltage check shows less than 22.5 volts in batery?

• A.

The battery shall be replaced or the battery electrical plug shall be disconnected.

• B.

The battery should be charged from external electric power before it is used.

• C.

The battery should be monitored closely during APU operation.

• D.

The battery shall be left connected but not used during APU operation.

A. The battery shall be replaced or the battery electrical plug shall be disconnected.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-6.1, WARNING CHANGE 7 T.O. 1C-5A-2-4CL-2, PAGE 3-4, WARNING

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• 12.

### What is the APU's maximum start time from start light to "ON SPEED" 0 degrees F and above.

• A.

20 seconds

• B.

60 seconds

• C.

30 seconds

• D.

80 seconds

C. 30 seconds
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-4, step 3b. (1)

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• 13.

### On initial start with the compartment door open following APU fuel/oil system component removal or installation, a fire guard with a serviseable fire extinguisher will be required to leak check the APU during start. That individual's duties are________?

• A.

The fire guard will be positioned at the APU and will establish communication with the flight engineer's station.

• B.

During start the fire guard will closely examine the APU for evidence of leaks especially from fuel, oil, or hydraulic fluid.

• C.

If any leaks or substandard conditions are noted, the fire guard will notify the flight engineer's station. The start will be aborted and the leaks or substandard conditions corrected prior to attempting another start.

• D.

The fire guard will comply with all of the above.

D. The fire guard will comply with all of the above.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-23, WARNING

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• 14.

### What position must the battery switch be in for a fire handle shut down?

• A.

Must be in NORM or STBY position: if modified by TCTO 1C-5-736; ON position.

• B.

Must be in NORM position, if modified by TCTO 1C-5-736; ON position.

• C.

Must be in OFF position,if modified by TCTO 1C-5-736 ON position.

• D.

Must be in EXT PWR position, if modified by TCTO 1C-5-736; ON position.

A. Must be in NORM or STBY position: if modified by TCTO 1C-5-736; ON position.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-6.3, WARNING CHANGE 10

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• 15.

### WHAT IS THE LOCATION OF THE APU FIRE EXTINGUISHER BOTTLE SELECT SWITCHES?

• A.

PILOT'S CENTER INSTRUMENT PANEL.

• B.

FLIGHT ENGINEER'S PANEL AND LOADMASTER'S FORWARD CONTROL PANEL

• C.

LOADMASTER'S FORWARD CONTROL PANEL AND PILOT'S CENTER PANEL

• D.

FLIGHT ENGINEER'S PANEL AND LOADMASTER'S AFT CONTROL PANEL

B. FLIGHT ENGINEER'S PANEL AND LOADMASTER'S FORWARD CONTROL PANEL
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-1, STEP 1B & T.O. 1C-5A-2-4CL-2, PAGE 3-9 STEP 19B

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• 16.

### TO PREVENT APU HOT STARTS THE ACCUMULATOR SHOULD BE NO LESS THAN _________ PSI

• A.

2700

• B.

3000

• C.

2800

• D.

3150

C. 2800
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-17, STEP I (2), (3)

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• 17.

### HOW LONG CAN THE APU OPERATE WITH THE EGT BETWEEN 691 DEGREES C AND 746 DEGREES C?

• A.

30 SECONDS

• B.

1 MINUTE

• C.

2 MINUTES

• D.

3 MINUTES

D. 3 MINUTES
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-3 - 4-4, ITEM 3.A (3)

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• 18.

### WHAT MUST BE AVAILABLE IF THE APU IS TO BE OPERATED WITH THE COMPARTMENT DOOR OPEN?

• A.

A FIRE GUARD MUST BE AVAILABLE WITH AN APU TESTER.

• B.

A FIRE GUARD MUST BE AVAILABLE WITH A TWO-WAY RADIO.

• C.

A FIRE GUARD WITH AN ADEQUATE FIRE EXTINGUISHER MUST BE AT THE COMPARTMENT.

• D.

A FIRE GUARD WITH AN ADEQUATE COMMUNICATION SYSTEM MUST BE AT THE COMPARTMENT.

C. A FIRE GUARD WITH AN ADEQUATE FIRE EXTINGUISHER MUST BE AT THE COMPARTMENT.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 2-1 CAUTION

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• 19.

### IF THE APU GENERATOR FAIL LIGHT COMES ON DURING APU OPERATION, WHAT MUST YOU DO?

• A.

PLACE GENERATOR SWITCH TO OFF POSITION.

• B.

SELECT THE OTHER APU GENERATOR.

• C.

PLACE GENERATOR CONTROL SWITCH TO OFF AND CONTINUE TO OPERATE.

• D.

IMMEDIATELY SHUT DOWN THE APU.

D. IMMEDIATELY SHUT DOWN THE APU.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 11-27, CAUTION

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• 20.

### WHAT MUST BE OPERATING BEFORE STARTING THE ATM'S TO RECHARGE THE APU START ACCUMULATORS?

• A.

SYSTEM PRESSURE MUST BE 300 PSI.

• B.

BLEED MANIFOLD PRESSURE MUST BE 50 PSI.

• C.

THE ELECTRIC SUCTION BOOST PUMPS BE ON.

• D.

ALL POWER TRANSFER SWITCHES MUST BE ON.

C. THE ELECTRIC SUCTION BOOST PUMPS BE ON.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 5-3, CAUTION

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• 21.

### DURING NORMAL OPERATION, THE APU GENERATOR AC LOAD-METER SHOULD NOT EXCEED WHICH LIMIT?

• A.

• B.

• C.

• D.

Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 11-27, CAUTION

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• 22.

### DURING OPERATION OF THE ATM, A QUALIFIED OPERATOR WILL BE LOCATED WHERE?

• A.

AT THE PILOT'S STATION.

• B.

AT THE FORWARD LOADMASTER'S CONTROL PANEL.

• C.

AT THE FLIGHT ENGINEER'S STATION.

• D.

AT THE APU/ATM COMPARTMENT DOOR.

C. AT THE FLIGHT ENGINEER'S STATION.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 5-4, CAUTION

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• 23.

### WITH EITHER APU GENERATOR SUPPLYING AIRCRAFT POWER, THE OPERATOR WILL FIND ALL BUSES POWERED?

• A.

EXCEPT #2 AND #3 MAIN AC BUSES.

• B.

EXCEPT THE MONITOR BUSES.

• C.

EXCEPT THE DC POWERED BUSES.

• D.

EXCEPT THE #2 AND #3 DC BUSES

B. EXCEPT THE MONITOR BUSES.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-6, NOTE

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• 24.

### WHAT EFFECT WOULD HAVING THE AIRCRAFT ON JACKS, OR TWO MAIN LANDING GEAR CROSS KNEELED, OR #1 TOUCHDOWN RELAY CIRCUIT BREAKER PULLED HAVE ON THE APU?

• A.

THE AUDIBLE HORN WILL NOT SOUND.

• B.

THE APU DOOR WILL NOT OPEN FULLY AND THE AUDIBLE HORN WILL NOT SOUND.

• C.

THE APU LOW OIL PRESSURE SWITCH WILL BE OVERRIDDEN, PROHIBITING LOW OIL PRESSURE PROTECTION; THE APU DOOR WILL NOT OPEN FULLY; THE APU FIRE WARNING AUDIBLE HORN WILL NOT SOUND.

• D.

THE APU LOW OIL PRESSURE SWITCH WILL BE OVERRIDDEN, PROHIBITING LOW OIL PRESSURE PROTECTION; THE APU FIRE WARNING AUDIBLE HORN WILL NOT SOUND.

D. THE APU LOW OIL PRESSURE SWITCH WILL BE OVERRIDDEN, PROHIBITING LOW OIL PRESSURE PROTECTION; THE APU FIRE WARNING AUDIBLE HORN WILL NOT SOUND.
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 3-24, CAUTION

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• 25.

### WITH THE APU OPERATING, WHAT IS THE MAX CONTINUOUS EGT?

• A.

691 DEGREES C

• B.

715 DEGREES C

• C.

630 DEGREES C

• D.

714 DEGREES C

A. 691 DEGREES C
Explanation
REFERENCE: T.O. 1C-5A-2-4CL-2, PAGE 4-3 - 4-4 ITEM 3A (4)

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• Nov 15, 2023
Quiz Edited by
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• Jul 20, 2012
Quiz Created by
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