Overheating Battery on B777

[skylark777]

Hi,

In case of an overheating battery problem in flight with the B777.
(For Example)
When selecting the ELEC page on the Display Select Pannel "DSP", you noticed at the bottom of the concerned page, a very high level of " Battery Amps" for a While (30 min, 01H00 ?)

-What would be the good & right decision ?
-What will happen, if the Main Battery get disconnected at 3 hours of a suitable airport ?

I'll be very pleased to get your feelings and advices in order to think the matter over this question...

-What will you do ?

;)

Many thanks,

[777fly]

......what would you do?....

My question would be 'what could you do?' and the answer is 'nothing'.

The B777 electrical system is completely automatic in operation and faults are detected and isolated without pilot action. The battery charger gets power from the ground service bus and in flight that bus is powered by the right main AC bus. To kill the the right main AC bus would require opening of the right bus tie breaker and selecting the right main and backup generators off. Would you seriously consider trying that without guidance of a non normal checklist?
Your B777 technical course should have emphasized that 'EICAS is king' . If it does not appear on EICAS there is nothing you should do. In flight status messages are advisory only and should not be a basis for unguided troubleshooting.
The main use of the battery is for initial power up and APU starting. If it fails or is isolated in flight it is of little consequence, given the multiple power sources available, even on a 3 hour single engine diversion.

I suggest you stop worrying and leave the system to look after itself.

[skylark777]

Hi,

Many thanks for your reply and advices...
Despite your accurate electrical description in order the remind how the system works, I knew already that the system works automatically, and above all, boeing doesn't mention any crew action for such abnormals cases.

-I do beleive that a "Battery Runaway" always be a significant an serious problem to considers.
-My opinion is to be prepare to consider such problems.

Thanks anyway...:ok:

[skylark777]

Sorry,
I should have write "A battery thermal runaway"

Best,

[linedriva]

I agree with 777fly - there isn't anything that Boeing recommends.

From the Non Normal Checklist introduction (also in the FCTM)

"It should be noted that, in determining the safest course of action, troubleshooting, i.e. taking steps beyond published non-normal checklist steps, may cause further loss of system function or system failure. Troubleshooting should only be considered when completion of the published non-normal checklist results in an unacceptable situation"

There was a reference regarding not using synoptic displays as a basis for doing a non normal checklist, but I can't find it at the moment.

So for me, I'd be sitting on my hands and monitoring.

[cwatters]

A B777 overwater flight experiences an overheating main battery which can only be disconnected as an... - NASA ASRS (http://www.37000feet.com/report/554274/B777-overwater-flight-experiences-an-overheating-main-battery-which-can-only)

A B777 in cruise at FL370 declared an emergency and diverted due to a main ships battery overheating... - NASA ASRS (http://www.37000feet.com/report/552790/B777-in-cruise-at-FL370-declared-an-emergency-and-diverted-due)

[skylark777]

Thanks, I didn't know about this...
Very instructive...
I guess we always can deviate from SOP & Procedures in "extremes situations" with good Captain jugement...

;)

[Graybeard]

Back in the '90s, there was a KLM (Martinair?) 767 enroute from AMS to JFK in which the electrical systems shut down one by one. They landed in KBOS with no flaps, etc. A battery may have been intermittent or disconnected.

The plane was then ferried to Boeing, where they could find nothing, IIRC. I never did see a full report on it. Does anybody have a ref?

[TopSwiss 737]

It was a Martinair B767, enroute from AMS to MCO.

More details here (http://www.fss.aero/accident-reports/look.php?report_key=1388) and here (http://aviation-safety.net/database/record.php?id=19960528-0).

TS737

[Graybeard]

Thanks for the links, TopSwiss. Those guys earned their pay that day. They could easily have been overwhelmed. Airliners are supposed to be able to tolerate single point failures, beyond primary structure, but that one comes close.

I wonder what's happened to that plane and its mates, and wonder more if there was ever a repeat performance?

There was also an MD-82 whose main battery exploded while the plane was being towed across KSFO from gate to hangar in about 1987.

Be careful, ya' hear?

GB