The UK Air Accident Investigation branch has published a Special Bulletin regarding the Ethiopian Airlines 787 incident at Heathrow last Friday at http://www.aaib.gov.uk/cms_resources.cfm?file=/S5-2013%20ET-AOP.pdf
In it there are two recommendations that have been made – which does have implications for the world-wide fleet of 787’s, as well as other aircraft.
- It is recommended that the Federal Aviation Administration initiate action for making inert the Honeywell International RESCU406AFN fixed Emergency Locator Transmitter system in Boeing 787 aircraft until appropriate airworthiness actions can be completed.
- It is recommended that the Federal Aviation Administration, in association with other regulatory authorities, conduct a safety review of installations of Lithium-powered Emergency Locator Transmitter systems in other aircraft types and, where appropriate, initiate airworthiness action.
Source: AAIB Special Bulletin – http://www.aaib.gov.uk/cms_resources.cfm?file=/S5-2013%20ET-AOP.pdf
The incident that involved 13 appliance attending to the plane at one point, closing London Heathrow for 90 minutes. Whilst investigators have yet to reach a firm conclusion to what started the incident on board, the investigation has turned from being related to the battery issues the 787 has had – into something else very quickly, and focused in on the Emergency Location Transmitter (ETL). This is a device that makes a plane easier to find in case of an emergency.
Although the plane was plugged into a ground power source when it had reached its holding spot, the power had been switched off to the plane.
The inquiry notes that
“There are no other aircraft systems in this vicinity (of the ETL) which, with the aircraft unpowered, contain stored energy capable of initiating a fire in the area of heat damage”
The fire was tackled initially with a hand-held halon extinguisher, before moving onto water hoses.
The AAIB notes that
“Had this event occurred in flight it could pose a significant safety concern and raise challenges for the cabin crew in tackling the resulting fire”.
Fitted aboard the 787 in that area is a Honeywell’s Rescu406AFN transmitter. This device contains batteries to power it in an emergency, based on lithium-manganese dioxide batteries. An examination of the battery has noted there is “disruption” in the area of the battery cells, but it isn’t clear if this is due to a battery short.
Honeywell has deployed over 6000 units, with the incident aboard the Ethiopian 787 being the only one which has had a thermal event in it.
Boeing has responded to the AAIB investigation stating
Boeing supports the two recommendations from the UK Air Accidents Investigation Branch (AAIB), which we think are reasonable precautionary measures to take as the investigation proceeds.
Honeywell International agrees with switching off the ETL’s whilst investigations continue, but it was “premature to jump to conclusions”.
There are still lots of questions still to answer from the source of the ignition of the incident to if the aircraft is economically repairable… if it is repairable according to http://www.bizjournals.com/seattle/news/2013/07/15/question-of-repair-costs-for-ethiopian.html?page=all
The story of ET-AOP – Queen of Sheba – has a long way to run…
Enough evidence to go back to ni cad or nimh batteries yet?
surely the extra weight would not be near the loss in space and fuel to justify their use over lighter lith packs