APU Limitations

Question 1

%N for amber font

Answer 1

102%

Question 2

%N for auto shutdown

Answer 2

107% or greater

Question 3

EGT for amber font

Answer 3

within 33C of current max EGT

Question 4

EGT for auto shutdown

Answer 4

computer calculated

Question 5

%N for AVAIL

Answer 5

99.5% or 95% for > 2 seconds

Question 6

Min batt voltage to start

Answer 6

25.5V, if less charge for 20 mins

Question 7

When can you press APU START?

Answer 7

5 seconds after MASTER SW has been depressed and no LOW OIL LEVEL advisory

Question 8

Max START EGT?

Answer 8

1000C

Question 9

Max operating EGT?

Answer 9

700C

Question 10

When can you NOT check for the LOW OIL LEVEL during APU start?

Answer 10

Battery starts

Question 11

After turning batteries to AUTO how much time do you have to start the APU?

Answer 11

30 minutes

Question 12

After the batteries have been on for 35 minutes how much batt capacity is remaining?

Answer 12

<25%

Question 13

Approx how long until APU available after start is engaged?

Answer 13

~1 minute

Question 14

After AVAIL extinguishes during shutdown, how long do you leave batteries on for?

Answer 14

2 minutes

Question 15

Max service ceiling

Answer 15

FL390

Question 16

Max altitude to start on batteries only

Answer 16

FL250

Question 17

Max altitude to power one AC pack

Answer 17

FL200

Question 18

Max altitude to power two AC packs

Answer 18

FL150

Question 19

APU starter limit

Answer 19

After 3 consec starts attempts allow 60 minutes for cool down

Question 20

Max alt to start engines

Answer 20

8,000 ft

Question 21

Max alt for APU anti-ice

Answer 21

TRICK, you can’t use APU for anti-ice

Question 22

What is the cooling period for emergency shutdown?

Answer 22

None