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AA 757 departed runway at ORD - no injuries

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AA 757 departed runway at ORD - no injuries

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Old 25th Oct 2008, 03:55
  #21 (permalink)  
 
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"Other than the battery discharge light there were no other abnormal indications."

Shouldn't the battery discharging be a very big clue?
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Old 25th Oct 2008, 07:53
  #22 (permalink)  
 
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What this crew needed was a battery charger mode switch.
Standard fit with most TriStars flying today, when switched to the alternate position, keeps the battery charger on line, charging the ships battery.

Ahhhh, Lockheed, just a better design.
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Old 25th Oct 2008, 12:31
  #23 (permalink)  
 
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Hard to say....hold fire

I can only comment if this happened on a B737NG.

1. If the 'Standby Power Off' light illuminates, the QRH gives a few lines on what's wrong. The corrective action is:

STANDBY POWER switch.......BAT

End of checklist.

If there's excessive battery discharge (in the 737) the 'BAT DISCHARGE' light will illuminate. In this case the QRH states the obvious that's there's excessive battery discharge and Note: Fully charged batteries provide a minimum of 60 minutes of standby power.

End of checklist.

The second checklist is your heads up to get on terra firma.

Can any 737 engineers tell me if the STANDBY POWER switch is placed to BAT that the batteries should continue to be charged?

IR
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Old 25th Oct 2008, 13:53
  #24 (permalink)  
 
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This is from the Boeing Maint. Ref. Manual

The main battery charger cannot go into the charge mode
during any of these conditions:
* Fueling station door open
* APU start
* Standby power switch (P5-5) in the BAT position
* Standby power switch (P5-5) in the AUTO position, battery
switch ON, and DC BUS 1 and AC TRANSFER BUS 1 do not
have power
* Main battery overheat.

The auxiliary battery charger cannot go into the charge mode
during any of these conditions:

* Standby power switch (P5-5) in the BAT position
* Standby power switch (P5-5) in the AUTO position, battery
switch ON and DC BUS 1 and AC TRANSFER BUS 1 do not
have power.
* Auxiliary battery overheat.
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Old 25th Oct 2008, 13:56
  #25 (permalink)  
 
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Possibly not relevant but.....it is a Boeing

B744 Standby Power Selector

BAT-

Powers...battery bus....from battery

Disables battery chargers

Note

BAT position for ground maintenance only .... power is available for a minimum of 30 minutes.
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Old 25th Oct 2008, 14:42
  #26 (permalink)  
 
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While en route the flightcrew received an AIR/GRD SYS message, an illumination of the standby power bus OFF light, and several advisory and status messages on the engine indicating and crew alert system (EICAS). ... QRH ... AIR/GND SYS message. The flight crew then followed the procedure referenced in the QRH for STANDBY BUS OFF by turning the standby power selector to the BAT position. The QRH procedure also referenced that, "The battery will provide bus power for approximately 30 minutes." The airplane systems stabilized with several items inoperative and the captain contacted maintenance technical support and subsequently elected to continue the flight on battery power
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. ... over western Michigan and the captain elected ... divert to ORD.
It appears that, other than the BAT SB discharge light, there were no other abnormal electrical indications. Once all 4 busses failed, they realized they had a total different set of problems than what the QRH led them to believe. They didn't want to go around to a longer runway with the flight control difficulties. All told, an excellent outcome. Well done guys.

73
What depth of systems knowledge and logic would lead to this sort of conclusion?
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Old 25th Oct 2008, 15:30
  #27 (permalink)  
 
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When we action a stadby power check on the ground on a B757/B767 we select Standby power to BAT. The Battery and APU battery discharge lights come on after a few seconds. We leave it at BAT for a minute then select AUTO. We look on the Elec Maint page and watch that both batteries recharge. It takes over a minute for the batteries to come back to normal.

I hope that lessons have been learned here. When the QRH says 30 mins, it does mean land at once. Perhaps this should be emphasised for those that don't understand. As this crew found out there are loads of circuits connected to the Bat and Stdby busses that make life difficult when they fail.

With hindsight they would have been better off reselecting the Standby switch to Auto until they were within 30mins of landing.

The battery lasted longer than 30mins because a lot of the systems were still using main bus power as it was available. The 30 mins is when you only have battery power. Many systems have dual supplies, they will use AC Main bus power when available, and change to Stdby power when it is not.
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Old 25th Oct 2008, 17:21
  #28 (permalink)  
 
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Am I missing something here?

As I see it:

The crew got a warning that the Standby Busses were not powered, and swirched them to Battery supply, giving them at least 30 minutes of power to both busses.

Instead of using that time to get on the ground without further incident they elect to continue on to their destination.


On all aircraft I have flown over many years, going onto battery power inflight is a lifeline of limited duration to get you on the ground as soon as possible.

Is it possible that professional pilots understand their aircraft so poorly that they think everything is ok in this situation?

The mind boggles.
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Old 25th Oct 2008, 17:34
  #29 (permalink)  
 
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Is it possible that professional pilots understand their aircraft so poorly that they think everything is ok in this situation?

The mind boggles.
Yes, and the mind does boggle.
Crews nowadays are actually taught very little about aircraft systems at many airlines in my experience, so many times truly do not comprehend the possible problems involved.

This ain't good, as one might expect.
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Old 25th Oct 2008, 17:47
  #30 (permalink)  
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Am I missing something here?
The Captain was an instructor.

And he called maintenance control to see whether it was safe to continue.

That's the rumors on another board, anyway.....
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Old 25th Oct 2008, 19:01
  #31 (permalink)  
 
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...and probably switching the Stby Bus Switch to AUTO would have recharged the batteries so for the landing they would have had all necessary system...

Heck, alone placing the switch to AUTO without charged batteries would have restored each system except for the STBY DC Bus if I understood the situation correctly.

Last edited by Ka8 Flyer; 25th Oct 2008 at 19:31.
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Old 25th Oct 2008, 19:02
  #32 (permalink)  
 
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The Captain was an instructor.
And he called maintenance control to see whether it was safe to continue.
The blind leading the blind, so to speak.
Perhaps some now will understand just why I am, personally, so critical of American Airlines, and their so-called operating procedures.

Landing during a big thunderstorm at Little Rock...with a system Chief Pilot at the helm, no less....

Cali, Colombia, rushed approach, no briefing, descending toward a clearly unsuitable waypoint, pulling up with speed brakes extended to avoid GPWS alerts....

A300-600 pilot induced rudder inputs, so that engines, vertical tail soon departed...

Hello, anyone see a cause and effect here?
I sure as hell do.

The oldtimers in charge of training have long since retired, and the new bunch 'in charge' haven't a clue.

Long story short...expect more of the same type of nonsense.

Last edited by 411A; 26th Oct 2008 at 06:43.
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Old 26th Oct 2008, 02:09
  #33 (permalink)  
 
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411A.

Why the big agenda against AA? Maybe they turned you down? AA training is very good. Yes, they have had accidents that should have not happened but so has every other airline. Maybe you need to look at your need to look down at things that have happened accidentaly and listen to people that have questioned your credibility recently.
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Old 26th Oct 2008, 03:15
  #34 (permalink)  
 
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From the AA Flight Department -

SUBJ: NEW ELECTRICAL CHECKLISTS

A RECENT FLIGHT DIVERTED INTO ORD AFTER COMPLETELY DISCHARGING
THE BATTERY IN FLIGHT. THE CREW FOLLOWED THE CHECKLISTS
CORRECTLY WHICH COME DIRECTLY FROM BOEING AND DID NOT DIRECT
THE CREW TO LAND AT THE NEAREST SUITABLE AIRPORT. I WILL BE
ISSUING A PINK BULLETIN THAT WILL REPLACE YOUR CURRENT QRH
TABS 9 AND 10 CHECKLISTS AS WELL AS THE ENTIRE ELEC SECTION
CHECKLISTS. MOST IMPORTANTLY, THESE NEW CHECKLISTS WILL DIRECT
THE CREW TO LAND THE AIRCRAFT AT THE NEAREST SUITABLE AIRPORT
IF THE BATTERY IS DISCHARGING AS WELL AS ADD A LIST OF ALL
ITEMS ON THE STANDBY AC, STANDBY DC, BATTERY BUS AND HOT
BATTERY BUS. YOU WILL SEE THESE CHECKLIST REVISIONS SOON.

FOR THE FLEET SUPPORT TEAM
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Old 26th Oct 2008, 03:50
  #35 (permalink)  
 
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It was a good thing it was not a 767 200 domestic aircraft. No battery means no landing gear and no flaps if that is the only power available. Since this 757 had normal ac for main busses the 767 probably would have been ok. If the 767 200 gets down to battery only on domestic versions the battery is required for gear and flaps.
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Old 26th Oct 2008, 04:53
  #36 (permalink)  
 
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Why the big agenda against AA? Maybe they turned you down?
No, sorry, never applied.
If we look at the accidents that I specified in my prior post, a pattern of we know better because we are American Airlines comes through loud and clear.
I would appear to me that something is seriously wrong at American, as the root cause of their accidents simply does not lend itself to just random acts of forgetfulness.
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Old 26th Oct 2008, 06:34
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I am no systems expert but It always amazes me how many people (that are current and qualified on the 75/ 6) think that the RAT is a source of electrical power
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Old 26th Oct 2008, 06:50
  #38 (permalink)  
 
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hey 411a,

fatigue is insidious, and in studies, equates to elevated levels of blood alcohol content. bad decisions are easier to make, as judgment is impaired. (LIT)

some turbulence on departure (preceeding 747?) at JFK for the A300-600 (AA587)...and they really think the FO tore the tail off. yeah right. 2 or 3 FULL rudder throws were recorded...hmmm, I wonder if the rudder could have already been gone/flapping in the wind (AirTransat?), and maybe THAT'S why it was recorded that way. Like a pilot would actually go 3 full throws of the rudder- back and forth.

but, it's always easier to blame the dead pilots, right?

a real AA hater, huh?

kc135777
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Old 26th Oct 2008, 09:04
  #39 (permalink)  
 
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Like a pilot would actually go 3 full throws of the rudder- back and forth.
Recorded on the DFDR, KC135777, for all to see.
And then we come to the AA MD80's...how many was it that the FAA grounded?
How big was the fine?
And Cali...what excuse do you have there?

The AA accident facts speak for themselves.
A very sad story.
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Old 26th Oct 2008, 09:46
  #40 (permalink)  
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A writer at the Seattle PI has questions from a former Boeing designer, asking why the APU was not used (link):
As the guy who designed the auxiliary power unit installation on the 757 in the early 1980s, you'll have to explain to me why the APU wasn't started to provide limitless electrical power for the airplane for the duration of the flight. I read the NTSB prelim report, and it did not mention the APU at all. An APU can be started at any altitude using its own dedicated 24v battery, and once started, capable of providing 90 kVA (same as a single engine generator) until the airplane runs out of fuel. Yes, some non-essential electrical loads must be turned off when only one generator is operative, but that in no way would affect safety of flight.

It is permissible to dispatch an airplane with an inoperative APU (and with inop thrust reversers), but nothing was mentioned in the NTSB's prelim report. Strange.

The APU is the primary backup for main engine generator failures. Sounds like the flight crew needs some remidial training or the NTSB wasn't telling all.

Tim Repp (Boeing retired)
Gig Harbor
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