APU Flashcards

1
Q

What is the power source for the APU boost pump?

A

24-28V DC (battery)

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2
Q

What systems does the APU indirectly supply?

A

Hydraulics and Generators

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3
Q

What is the Nr range to avoid during APU operation?

A

94-96%

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4
Q

What is the maximum number of APU start attempts permitted in one hour?

A

3

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5
Q

What precaution is to be taken for when unauthorized personnel will be in the cockpit?

A

Pop the APU circuit breaker (right EFAB)

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6
Q

What is the only APU warning?

A

APU fire

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7
Q

What is the only APU caution?

A

APU on

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8
Q

Where does the APU receive fuel from?

A

AFT fuel cell

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9
Q

APU oil level is found where?

A

The sight glass

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10
Q

When is APU bleed air provided?

A

Once APU reaches 95%

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11
Q

Where is the APU located?

A

Inboard of the right engine nacelle in the aft equipment bay under a Kevlar enclosure

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12
Q

What is the approximate fuel burn for the APU per hour?

A

175 lbs/hour

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13
Q

What three things does the APU enclosure provide for the APU

A
  1. Allows cool air to flow across the APU for cooling
  2. The inlet screen is used to allow ambient air to be used for combustion
  3. Confines the APU in the event of fire for extinguishing purposes
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14
Q

What does the APU electronic control unit provide?

A

Provides for operational sequencing control for automatic starting PTO clutch operation, normal operations and APU operation

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15
Q

What does the PTO clutch provide?

A

Provides the coupling and de-coupling between the APU and the main XMSN accessory gearbox, through the number 7 driveshaft

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16
Q

Where is the APU oil level sight gauge located?

A

Right side of the APU and can be viewed through the access port on the bottom of the number two engine nacelle

17
Q

When viewing the APU oil level where should the oil level be on the sight gauge

A

The ball bearing should be midway on the sight gauge

18
Q

The APU is divided into two major sections what are they?

A

Accessory section
and
power turbine section

19
Q

The PTO clutch normally engaged when the APU reaches what percent?

A

Engaged at 60% APU speed

20
Q

During cold weather operation with the XMSN oil temp below 0 F when will the PTO clutch engage?

A

Will engage at 95% APU speed

21
Q

The load control valve will open at 95% APU SPEED and will REMAIN OPEN UNTIL WHAT TWO ACTIONS OCCUR?

A

The APU is shutoff
Or
Fire/RDY push button is activated

22
Q

Where are the APU push buttons located?

A

Pilot power quadrant control panel

23
Q

What is the minimum aircraft requirements that must be present prior to starting APU?

A

Battery or external power
Minimum of 2600 PSI hyd pressure in utility hyd accumulator
Fuel in the aft fuel cell
APU oil level half full

24
Q

What is the maximum oil XMSN oil temp (on sys page) before APU must be turned off ?

A

XMSN TEMP Max 140 c

25
Q

What systems does the APU directly supply?

A

Directly provides air to the Integrated Pressurized Air System (IPAS) and engines.

26
Q

What is the APU shaft power output?

A

81 Shaft Horsepower (SHP).