During engine start on the ground, what is the recommended ON/OFF pattern for the 3rd through 5th attempts?

During engine start on the ground, what is the recommended ON/OFF pattern for the 3rd through 5th attempts?

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

Answer: (A)

In engine start procedures, after a couple of failed attempts you shift to longer cooling periods to protect the starter and engine from heat buildup and to let control systems reset. For the 3rd through 5th attempts on the CRJ-550 on the ground, the recommended pattern is 90 seconds of cranking (ON) followed by a 5-minute pause (OFF). The 90 seconds provides a complete chance to attempt a light-off, while the 5-minute OFF allows ample cooling of the starter, accessories, and engine so you don’t risk a hot start or equipment damage before the next try. The other patterns either jam too much cranking into one attempt or don’t give enough cooling time between attempts, making them less safe or effective for multiple starts.

In engine start procedures, after a couple of failed attempts you shift to longer cooling periods to protect the starter and engine from heat buildup and to let control systems reset. For the 3rd through 5th attempts on the CRJ-550 on the ground, the recommended pattern is 90 seconds of cranking (ON) followed by a 5-minute pause (OFF). The 90 seconds provides a complete chance to attempt a light-off, while the 5-minute OFF allows ample cooling of the starter, accessories, and engine so you don’t risk a hot start or equipment damage before the next try. The other patterns either jam too much cranking into one attempt or don’t give enough cooling time between attempts, making them less safe or effective for multiple starts.