Originally Posted by
aterpster
That could very well be the case. But, on the date of the accident a 727's standby power would have powered the captain's normal instruments plus (I think) VHF 1 and NAV 1.
It's been 35+ yrs...but, as I recall, the essential power selector had 5 positions - battery - gen 1 - 2 - 3 - apu. Normally in flight, essential power was on gen 3. The F/E IMMEDIATE response to a "9 light trip" (which is what you got on the elec panel if all gens failed) was the memory drill known as EDP - ESSENTIAL power selected to battery - DOWNLOAD electrical draws by turning off galley power, one pack to kill the pack fan, etc - POWER the buss by attempting to reset one or more generators.
It was theorized on UAL 266 that when the engine failed, the one remaining gen tripped due to overload, the F/E selected the essential power to bat, but, in the download process, inadvertantly turned off the bat switch instead of galley power as the two switches were in close proximity & neither had guards. At night, low altitude in the overcast, everything went dark.
In response to this accident, a guard was placed over the bat switch & the previously discussed third horizon was mandated.