Wow that is a real eye opener. Anyone know if there is any benefit other than cost saving. Particularly worrying would be Gol flying long distances over Brazil out of thirty minutes range of an airfield or All Nippon that had a couple of aircraft doing long range all business class services. That is the sort of information that would help me decide who not to fly with. Unlikely as the loss of all generators might be, the recent russian incident shows it is possible.

An eyeopener indeed. To explain why is was a bit surprised that there is actually a single battery option (although knowing nearly everything on a 737 is optional it shouldn't really be surprising), our generic transition training CBT provided by boeing when transitioning from classics to NGs told us "all Boeing 737 NGs are equipped with dual batteries" which seems to be some misinformation. Not really surprising as the boeing CBTs are not all that good anyway, but still...

Since all NG's are delivered 'ETOPS Capable' I guess the 'standard' would be 2 and you would probably have to argue to get 1?

EL AL too: (there is no "AUX BAT" position at the DC Selector)
Photos: Boeing 737-758 Aircraft Pictures | !!!!!!!!!!!!!!

Not sure what the battery(ies) would have to do with ETOPS, as the ETOPS portion of the flight is predicated on having the APU running to supply electrical power, if required.

Agreed, but I know which I would prefer mid-oggin!

With regard to 30 minutes battery duration with the single battery NG...

In the case of a complete AC power failure in an NG (unlikely), I have always considered the 30 minutes of battery duration to be employed only during the approach part of the recovery....you know, when you really need all those instrument thingies and talky things to get you to the right end of the runway going in the right direction.

Why would you drain the battery(s) in level cruise flight, when there are quite enough indications of heading, altitude and speed, then have not enough left when you really need it, to shoot a normal(ish) approach (VHF1, NAV1, ADF1) if the need arose.

As an aside...well almost...in a dual battery NG,
1/ the secondary battery is not normally used for anything at all, the ONLY time the two batteries are connected is when standby power is activated, and
2/ if you ever arrive at the airplane to start the APU, and find the primary battery isn't up to it, selecting standby power on to connect the two batteries won't help, since selecting the APU to start is the only time, with standby power selected, that the two batteries are disconnected from each other.

Cheers,
ew73

Everyone is entitled to their point of view. I think I am with BOAC on this one, as are obviously the majority of NG operators judging by the list. Having one battery can hardly improve safety as to whether it seriously reduces it is the question. Anyone have any examples where having two batteries has helped?

In my company we have most of the NG with the dual battery config, but some (2 -800) has the single battery.

EK73 thanks for the /2 information: I didn't know about that :ok:

Obviously plenty of operators have single battery installations.
Having worked on 737's for nearly 30 years I have never seen personally a single aircraft that has lost all 3 gennys.
We run etops all the time aand fly in excess of 4 hours on a few legs.All single battery.Sure 2 or more of everything is great but given the record of the 737 classic and NG the lack of necessity speaks for itself imho.