Originally Posted by
WhatsaLizad?
FS,
Curious as well regarding the number of jet transport aircraft that have ended up on battery power. I am also unsure of the MEL practices around the world. Agreed that a triple generator failure would be extremely rare in the 737 case, but dispatch with 1 engine generator inop might have an effect on the probabilities given the sometimes temperamental aspects of APU's. The number of possible diversion runways available to become even more limited in the case of the MAX after losing all generators.
The 737 is ranging far more than it has in the last 50 years.
I only have experience of one company’s ETOPS requirements on the NG so it’s not definitive, but we couldn’t dispatch an ETOPS flight unless both engine generators and the APU generator was serviceable. In flight the APU had to be started prior to the ETOPS entry point and if it didn’t start or one of the engine driven generators failed prior to the entry point then we had to re-route to ensure we remained within one hour of a suitable airfield. I would imagine that would apply to most ETOPS aircraft unless they have a RAT that can provide sufficient power if one of the other sources fails.