Another 787 electrical/smoke incident (on ground)

[RR_NDB]

What caused the failure?

Hi,

There are two possibilities (discarding other less probable factors):

1. A cell failure triggering failures to other cells.
   
2. A failure of electronic circuitry. Charger(s), current limiters or sensor(s)

I hope the pack is protected by independent cell sensors (temperature and voltage) such as used in serious Lithium battery pack designs.

But there is a threat: May they learn what caused the incident?

It seems very difficult to identify the trigger. In this scenario certainly we have a problem. And a threat that will require a change.

What kind of change? IMO the proper action should be a redundant change:

1. Repositioning of the pack(s)
   
2. Better sensors in the pack(s)
   
3. Higher reliability electronic circuitry
   
4. Data monitoring (a data recorder)

As a designer (*) with a passion for Reliability i consider this a serious issue and it seems FAA (review) started very well. We hope the bureaucrats to have no way to suppress the Technical people voice.

This is common and the example mentioned by RobertS975 on the Challenger disaster is typical.


* (Started to design with vacuum tubes after working maintaining aircraft radios like Collins ART-13, ARC-2, BC348, ARR15 and ground station equipt. (HF, VHF and Teletype gear) like 4WTFA, ERCO CFR etc.)