On the ground, what is the crank cycle for starting engines 3 through 5?

• A. 90 seconds on, 5 minutes off
• B. 90 seconds on, 10 seconds off
• C. 120 seconds on, 5 minutes off
• D. 60 seconds on, 5 minutes off

Answer: (A)

Starting on the ground uses a careful crank cycle to protect the starter and power system while giving the engine a fair chance to light off. You crank for 90 seconds at a time to allow the engine to attempt a start, and if it hasn’t started within that window you stop and wait a 5-minute cooldown before trying again. The 5-minute off period lets the starter motor and electrical system cool down and recover, reducing the risk of overheating or damage and ensuring the next start attempt has sufficient power and stability. When starting engines 3 through 5, this same pattern is followed to manage heat and electrical load across the sequence.