How many start attempts are permitted for the APU starter motor in one hour?

How many start attempts are permitted for the APU starter motor in one hour?

• A. Three start attempts in one hour
• B. Two start attempts in one hour
• C. Four start attempts in one hour
• D. Five start attempts in one hour

Answer: (A)

APU starter motor starts are limited to protect the starter and the APU from overheating and excessive wear. In the CRJ-550, you’re allowed up to three start attempts within any 60-minute period. That means if the APU fails to start after three attempts, you must stop trying for the remainder of that hour and plan to retry later or bring maintenance into the loop. It’s important to count every start attempt, including aborted or unsuccessful starts, toward that limit. If more than three starts are needed, wait for the hour to roll over, or use alternate power or maintenance procedures as appropriate.

APU starter motor starts are limited to protect the starter and the APU from overheating and excessive wear. In the CRJ-550, you’re allowed up to three start attempts within any 60-minute period. That means if the APU fails to start after three attempts, you must stop trying for the remainder of that hour and plan to retry later or bring maintenance into the loop. It’s important to count every start attempt, including aborted or unsuccessful starts, toward that limit. If more than three starts are needed, wait for the hour to roll over, or use alternate power or maintenance procedures as appropriate.