American 757 flies on battery power, makes emergency landing at O'Hare

AWACSEng said:
Not sure. It may have something to do with our 8 generators and the way the power is distributed. The component regulates the frequency going to the bus. The mission systems are super sensitive to fluctuations in freqs. I referenced my pubs, and if that component fails, we do not lose all electrics, but it does restrict use of the mission systems. I got my components mixed up.
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Only now did it occur to me the E-3 has all the trons on board. It's going to draw a ton of power several times over the 707.
 
When the system is up, between 80-100 amps per generator.
 
Partial crosspost.

This is a post I made on the red board.

aterpster said:
They didn't have any attitude indicators, so they were down to altimeter, airspeed, and wet compass. (if I recall the 767 configuration correctly)
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Who said they were down to those instruments. From the accident report:

Approximately 1 hour and 40 minutes later, while in cruise flight, the battery power was depleted at which time several cockpit electrical systems began to fail.
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Nowhere does it say what those "several cockpit electrical systems" were.

More quotes from the report:

With the standby power selector in the BAT position, as selected by the flight crew, the main battery provided power to the hot battery bus, the battery bus, the AC standby bus, and the DC standby bus. In addition, the main battery charger was not receiving power, and thus the battery was not being recharged. When main battery power was depleted, all 4 of the aforementioned buses became unpowered.
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A total of four busses were involved. And none of them involved the normal electrical busses. Those busses are there to provide backup for the normal electrical busses and there is no indication that those busses failed. Given the information in the report, there is no indication that they lost either primary flight display, or any other systems necessary to successfully fly the aircraft and navigate to a successful landing.

Like I said before, given the information provided, we really have no idea what was really going on in the cockpit.
 
im glad that we have these airline guys to help explain stuff when these things happen. to someone used to flying equipment with pretty simple systems in a fairly simple operation, its hard to really understand all that goes on in a large aircraft during abnormal procedures.
 
We do have a 28 VDC system and a 28 VAC system, but most systems run off of 115 VAC/400HZ.
 
tonycondon said:
im glad that we have these airline guys to help explain stuff when these things happen. to someone used to flying equipment with pretty simple systems in a fairly simple operation, its hard to really understand all that goes on in a large aircraft during abnormal procedures.
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Yabut they answer too soon! They leave us in mid-air as we are leaping to conclusions....:goofy:

-Skip
 
I think they mean some of us come up with a plausable answer before others are done speculating!
 
Rotor&Wing said:
In the airline world there are set procedures to follow which doesn't allow the crew to "start flipping random switches" to see what happens. In the event of a popped circuit breaker the crew cannot reset unless the Abnormal Procedures instructs them to.

Not saying that sometimes it's discovered that the procedures are wrong and need revising. Also, the Abnormal Procedures can't take everything into account. I'm sure this incident will have all the carriers operating the 757/767 looking at this carefully.
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Absolutely right.
Sounds like the crew following the appropriate actions for the situation. Also, there's no mention of the fact that they still had TWO operating generators, one on each engine. They just lost the hot batt and batt bus. The AC and DC standy busses have alternate sources of power.

Now, don't get me wrong, there's a lot of stuff on those batt busses, but unless one specifically checked, there's no way of knowing that the batt is going south in the air. It's not SOP. However, the batt is checked on the ground before TO. There's also a list that tells what is lost, if the batt busses are unpowered.

I'd have to refer to my 757 manuals for more details, but I dumped them in the hangar after retiring off this plane a few years back.

This whole thing was probably handled as best as could be (remedial training not required), but I'd suspect an AD or perhaps some changes because of this. Also, technically, this was probably not even an emergency, but an irregular operation, but appropriate to call one and land as appropriate.
 
AWACSEng said:
I think they mean some of us come up with a plausable answer before others are done speculating!
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Yes. I hate it when a good opinion is interrupted by a few facts.... :yesnod:

-Skip
 
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I know what you mean Skip. But probably one of my biggest pet peeves is people (not so much the ones here) second guessing a crew after a mishap. I see it every day when another crew has a malfunction and they decide on a course of action different than what others may have done, but the outcome is the same: No injuries and airplane still intact. I think that is a problem with the type A personality. "If it's not my way, It's wrong!" That being said, let's assume away!
 
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