APU

Question 1

Max operating altitude

Answer 1

FL370

Question 2

Max starting altitude

Answer 2

FL300

Question 3

Max ac bleed altitude

Answer 3

FL150

Question 4

Max engine start bleed altitude

Answer 4

FL130

Question 5

Max speed w/ inop or unknown intake door

Answer 5

300 kias or apu on

Question 6

Pwr/fuel switch

Answer 6

Used for starting and stopping. When pressed on, in bite test performed, fuel sov opens, apu lcv opens, flow/APU fuel pump on, rpm and egt displays turn on.

Question 7

Apu start/stop switch

Answer 7

When pressed on, activates starter. Start message and light illuminates. Fuel and ignition at 4% rpm. Turns off at 50% rpm or 60sec active. Avail light on for bleed air at 99% rpm +4sec and APU lcv open message.

Question 8

Electrical power required

Answer 8

Main and APU batteries are required, minimum of 22V

Question 9

In flight starting

Answer 9

The pwr/fuel and start/stop switchlights must be pressed within 5 seconds of each other to avoid windmilling

Question 10

Stop sequence

Answer 10

Start/stop switchlight pressed to stop, fuel sov closes and APU shuts down. Intake door shuts. 60 second bite test where restarting is not possible. Once avail light goes out, pwr/fuel deselected.

Question 11

APU lcv switchlight

Answer 11

On the bleed panel, APU bleed air provides to the 10th stage for engine start and ac. Switchlight pushed and comes out, open illuminates. Check valve prevents reverse flow from the engine bleeds. Generator power has priority over providing bleed air.