For engine motoring on the ground 2nd through 5th attempts, what is the recommended pattern?

For engine motoring on the ground 2nd through 5th attempts, what is the recommended pattern?

• A. 30 Seconds ON, 5 Minutes OFF
• B. 90 Seconds ON, 5 Minutes OFF
• C. 60 Seconds ON, 5 Minutes OFF
• D. 120 Seconds ON, 10 Seconds OFF

Answer: (A)

When you’re motoring the engine on the ground for multiple attempts, the goal is to verify the engine can rotate and the start system is functioning without causing heat buildup. Limiting each motoring interval to 30 seconds provides enough rotation to check for normal spool and any obvious mechanical issues, without pushing components to overheating. The 5-minute OFF interval gives a thorough cooldown, letting the starter and engine components shed heat before the next attempt. Longer on-times would overheat the starter and related parts, while shorter off-times wouldn’t allow adequate cooling. So for the 2nd through 5th attempts, the pattern is 30 seconds ON, 5 minutes OFF.

When you’re motoring the engine on the ground for multiple attempts, the goal is to verify the engine can rotate and the start system is functioning without causing heat buildup. Limiting each motoring interval to 30 seconds provides enough rotation to check for normal spool and any obvious mechanical issues, without pushing components to overheating. The 5-minute OFF interval gives a thorough cooldown, letting the starter and engine components shed heat before the next attempt. Longer on-times would overheat the starter and related parts, while shorter off-times wouldn’t allow adequate cooling. So for the 2nd through 5th attempts, the pattern is 30 seconds ON, 5 minutes OFF.