Originally Posted by
propfails2FX
Had a good discussion with a high time Learjet pilot about the potential threat of resetting DC circuit breakers. The gentlemen stated he first heard about DC CBs being a threat in Learjet ground school. He also cited Air Canada Flight 797 which had a rear lavatory catch on fire after resetting a toilet motor CB.
Another military pilot was listening in on our conversation, and we both replied that it is common practice in the military to reset a DC breaker if it was not tied to a fuel system.
Prior to researching Flight 797, I've never heard of giving a CB "time to cool", and thinking twice about resetting one unless it was critical equipment for safety of flight.
What is your take on the topic?
At my last 135 job we were allowed to reset them after 5 minutes, my current one three minutes. Though we're only allowed to reset them once.
CBs work off heat and their size is directly related to the current the wire in the system can handle. That's why there is a cool down period. Never, ever just hold down a breaker once it has been reset.