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

mikea

mikea

Touchdown! Greaser!
Gone West
Joined
Feb 12, 2005
Messages
16,975
Location
Lake County, IL
Display Name
Display name:
iWin
The 185 passengers on an American Airlines 757 en route from Seattle to New York had no way of knowing the serious trouble their jet was in last month when the pilots switched to backup battery power because of a problem that occurred soon after takeoff.

Those batteries supply power to the plane for only about 30 minutes. But nearly two hours later, with the jet in cruise flight over Michigan, the electrical systems in the cockpit and, then, the cabin began to fail because the batteries were drained.

Without power, the plane's intercom went out and a flight attendant had to pass a note under the cockpit door to communicate with the crew.

As Flight 268 made an emergency landing at Chicago's O'Hare International Airport, vital systems to control the jet were not working, including some wing flaps. When the jet touched down, the engine thrust reversers did not work to slow the Boeing 757-200 and it barreled down the runway, leaving a long trail of skid marks as the pilot pushed hard on the brakes to try to stop.

...

http://seattlepi.nwsource.com/business/384988_jetscare25.html
Click to expand...

NTSB report:
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20081007X03940&key=1

Post incident investigation revealed a failure of the B1/B2 contacts in the K106 electrical relay. With the standby power selector in the AUTO position, this failure would have resulted in a loss of power to the battery bus and the DC standby bus, which would have resulted in the AIR/GND SYS message and illumination of the standby power bus OFF light which the flight crew received.

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.
Click to expand...
:yikes:

Are they saying the battery would have charged if they left the switch in another position?
 
mikea said:
Are they saying the battery would have charged if they left the switch in another position?
Click to expand...
I read that as they put it in the BAT position as indicated in the QRH based on the indications received. But, the QRH also indicated, "The battery will provide bus power for approximately 30 minutes."

Hence, it appears to be a mistake to continue a flight as long as they did ("Approximately 1 hour and 40 minutes"). A more immediate landing was likely in order. As with most checklist even in a small airplane, "Land as soon as practical" would be prudent.
 
What are all those warning lights?

Eh, dunno. Just keep flying.

:eek:
 
Wow, that is just incredible. It's extremely lucky that this situation didn't come out worse than it did. Everyone's alright, which is what matters most, but I can see a lot of room for improvement on the ADM there.
 
The funny things...

When my breaker blew just minutes away from takeoff I returned to land.

These guys declared an emergency at the last minute and then when they didnt' want to go around on the shorter runway ended up intentionally steering into the grass to slow down, when the reversers didn't work. :hairraise:

How about if they got the 13,000 foot runway in the first place after declaring?

Lesseee... They chose to use partial flaps. Why? :dunno:
 
Ron Levy said:
Oops. Someone's going back to the schoolhouse for retraining.
Click to expand...

Well, I am sure the crew did not make their decisions in a vacuum. Input was received from both maintenance and dispatch. I think there was some serious misunderstanding of how that particular system works on several levels. Maybe the crew will go back for more training. Maybe the maintenance manuals will be revised. Maybe the Flight handbook will be revised.

I do know that this will/has been looked at from an operational standpoint on several levels.

And I also know this raises more questions in my mind than it answers.
 
mikea said:
How about if they got the 13,000 foot runway in the first place after declaring?
Click to expand...

I wondered about that too, at the time.

Lesseee... They chose to use partial flaps. Why? :dunno:
Click to expand...

Straight from the report:

The systems required to slow the airplane on the runway appeared to indicate normal, and with the elevator control issues the flightcrew did not want to perform a go-around to land on a longer runway. Pitch control of the airplane was difficult so the flightcrew elected to stop the flap extension at 20 degrees.
Click to expand...

All of those reasons were valid as far as continuing the approach once they were established. HOWEVER, that really does not answer why they chose to land on the SHORTEST runway at O'Hare, rather than the longest.
 
mikea said:
"Every little thing" like almost losing the plane? :skeptical:
Click to expand...

All in a day's work.:D

I agree with Greg though, there's bound to be a lot more information about this incident than we've seen so far.
 
mikea said:
"Every little thing" like almost losing the plane? :skeptical:
Click to expand...

That is an assumption. There is more to this than is being reported. The NTSB report just reports FACTS. It does not really interpret them.
 
mikea said:
Lesseee... They chose to use partial flaps. Why? :dunno:
Click to expand...
As the airplane neared the runway on final approach, the flightcrew discovered that the elevator and standby elevator trim systems were inoperative. The captain then assisted the first officer on the flight controls and the approach to land was continued. The systems required to slow the airplane on the runway appeared to indicate normal, and with the elevator control issues the flightcrew did not want to perform a go-around to land on a longer runway. Pitch control of the airplane was difficult so the flightcrew elected to stop the flap extension at 20 degrees.
Click to expand...
Full power likely wasn't enough to bring the pitch up when they had limited or no elevator control. The report doesn't say but they probably landed pretty flat.

They should have taken the longest runway available to start with.
 
KennyFlys said:
Full power likely wasn't enough to bring the pitch up when they had limited or no elevator control.
Click to expand...

Well, it was the trim system inop, not the elevator itself. But yes, a go around thrust setting without trim may have been a handful. Like I said, the decision to continue the approach once it was established was probably a good one.
 
This appears to be another case of the classic Monday Morning Quarterback, or Pilot, that usually occurs after an incident. I'm sure the crew did the best they could and made the decisions they made with the information they were provided. Barring a severe case of rectal-caranial inversion, which an internal investigation would likely uncover, the end result seems to be as good as one could hope for.
 
Ted DuPuis said:
Wow, that is just incredible. It's extremely lucky that this situation didn't come out worse than it did. Everyone's alright, which is what matters most, but I can see a lot of room for improvement on the ADM there.
Click to expand...

Yes, thankfully it wasn't a fly by wire plane. That could have been very bad.
 
Does the 757 have a RAT? If it does, i'm sure a loss of all electrics is not as dire a situation as one would think. Some airplanes can also run the APU in flight to provide electricity and hydro power.
 
AWACSEng said:
Does the 757 have a RAT? If it does, i'm sure a loss of all electrics is not as dire a situation as one would think. Some airplanes can also run the APU in flight to provide electricity and hydro power.
Click to expand...

But if you lose a key relay on the power bus, all bets are off as to what power sources can be used.

I think they should have tried all of the switch postions, as well as finding the relay and beating on it. :cornut:

I think I would have noticed and tracked the battery voltage dropping. I did that in a car.
 
Last edited:
Good point, I forgot about the faulty relay. I have returned early many times from missions in the E-3 for batteries that were not charging in flight. No big deal untill you have a loss of all generators to go alond with it.
 
mikea said:
I think they should have tried all of the switch postions, as well as finding the relay and beating on it. :cornut:
Click to expand...

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.
 
mikea said:
I think I woudl have noticed and tracked the battery voltage dropping. I did that in a car.
Click to expand...

It isn't that simple. Finding a battery voltage can be several display pages deep. It isn't something that is in the forefront so to say.
 
Greg Bockelman said:
Except that the faulty relay was discovered after the fact. They didn't know it was faulty inflight. Unless I misread the report.
Click to expand...
Seems like that's a pretty weak design if a faulty relay can take out both sides of the electrical system with the exception of the battery. I agree, though, that there is a lot of the story missing.
 
Everskyward said:
Seems like that's a pretty weak design if a faulty relay can take out both sides of the electrical system with the exception of the battery. I agree, though, that there is a lot of the story missing.
Click to expand...

Sometimes flaws in the design aren't realized for years. A good example is the DC10 that blew out the #2 engine and lost all hydraulics.
 
Rotor&Wing said:
Sometimes flaws in the design aren't realized for years. A good example is the DC10 that blew out the #2 engine and lost all hydraulics.
Click to expand...
Or the 737 rudder control valve, even after three fatal crashes.
 
We have a single component on the E-3 that all power goes through. Ground, APU, and gernerator power.
 
AWACSEng said:
We have a single component on the E-3 that all power goes through. Ground, APU, and generator power.
Click to expand...
Is the original 707 designed that way or was that a specific milspec for its contracted design?
 
KennyFlys said:
Or the 737 rudder control valve, even after three fatal crashes.
Click to expand...

Actually, Ken, despite extensive efforts to prove the 737's rudder PCU design to be faulty, it has never been shown to be so. Subsequent changes in design were based upon hypothetical failure modes, but no failures have been actually proven.
 
SCCutler said:
Actually, Ken, despite extensive efforts to prove the 737's rudder PCU design to be faulty, it has never been shown to be so. Subsequent changes in design were based upon hypothetical failure modes, but no failures have been actually proven.
Click to expand...

You sure about that, Spike? I thought they proved they could get that result when they cooled the unit to cruise altitude temperatures.

Or was that another thing I am thinking of?
 
Greg Bockelman said:
You sure about that, Spike? I thought they proved they could get that result when they cooled the unit to cruise altitude temperatures.

Or was that another thing I am thinking of?
Click to expand...
That is exactly what they ultimately discovered. Fortunately, it was through the recovery of another incident where investigators were able to gain more information from earlier in the flight profile.
 
KennyFlys said:
Or the 737 rudder control valve, even after three fatal crashes.
Click to expand...

Greg Bockelman said:
You sure about that, Spike? I thought they proved they could get that result when they cooled the unit to cruise altitude temperatures.

Or was that another thing I am thinking of?
Click to expand...

KennyFlys said:
That is exactly what they ultimately discovered. Fortunately, it was through the recovery of another incident where investigators were able to gain more information from earlier in the flight profile.
Click to expand...


Well, not exactly.

One time (once), through the introduction of substantially-contaminated hydraulic fluid and a number of other outside-the-envelope modifications of conditions, a hardover condition was created... once. Repeated, never.

It was, of course, enough to justify a modification in design, and extra redundancy is never a bad thing. But PCU failure, or failure mode, have never been conclusively proven.
 
SCCutler said:
Well, not exactly.

One time (once), through the introduction of substantially-contaminated hydraulic fluid and a number of other outside-the-envelope modifications of conditions, a hardover condition was created... once. Repeated, never.

It was, of course, enough to justify a modification in design, and extra redundancy is never a bad thing. But PCU failure, or failure mode, have never been conclusively proven.
Click to expand...
Conclusively, no. But, they did cover every possible scenario and the conclusions made are more than plausible based on the findings.

http://www.ntsb.gov/publictn/1999/AAR9901.pdf
 
"Plausible conclusion" and "proved" are, indeed, two different things. In any event, they came up with enough to justify taking action in a context where inaction could have proven disastrous.
 
SCCutler said:
"Plausible conclusion" and "proved" are, indeed, two different things. In any event, they came up with enough to justify taking action in a context where inaction could have proven disastrous.
Click to expand...
Point taken, Counselor. :)
 
KennyFlys said:
Is the original 707 designed that way or was that a specific milspec for its contracted design?
Click to expand...

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.
 
You must log in or register to reply here.
Back
Top