PPRuNe Forums - View Single Post - Ethiopean 787 fire at Heathrow
View Single Post
Old 14th Jul 2013, 08:02
  #256 (permalink)  
alisoncc
 
Join Date: Apr 2006
Location: On the Bay, Vic, Oz
Age: 80
Posts: 415
Likes: 0
Received 0 Likes on 0 Posts
If I recollect correctly, the aircraft was being prepped for towing when the fired was noted. It may be pure coincidence but the "Grounding 787's" thread also makes mention of towing being an issue with the battery fire.

The APU Battery supplies the APU Hot Battery Bus ONLY. AFAIK it's job is to start the APU when no other power is available and power the Nav Lights when towing without APU. Thats it.

Just one thing. The towing switch is a selected function, not automatic. Depending on Main Batt charge state, there may only be enough power for a half hour tow.

My understanding of the refined battery system. The min discharge level has been increased. This will shut the battery down at a higher charge, but will mean that it can still be recharged in-situ if normal power is returned to the a/c.

EG A non-APU towing scenario, on bat only. instead of, say, 30 mins of useable power from the bat, one may only have 25 mins. The bat circuit automatically shuts off power and then when the GPU is connected the battery will recharge.

I could be wrong, but this seems the most logical outcome, otherwise we are still going to be changing batteries ad-nauseum due to towing operators not monitoring the bat state.
alisoncc is offline