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-   -   Ethiopean 787 fire at Heathrow (https://www.pprune.org/engineers-technicians/518971-ethiopean-787-fire-heathrow.html)

fenland787 13th July 2013 13:53


Presume that if the hull ignites @ 540 F, then.....
I don't think the the hull 'ignites' at 540F! I am not a composites person but I think the 540F number has more to do with the degradation of the material on exposure to high temperatures and there are, indeed, specifications for how hot things can be if they are in contact with the 787 composite. This material (or to be more accurate the resin within it) can self ignite given enough heat input but it takes a lot - around 31KW/sq metre with surface temps >500C or lower heat inputs if a flame is already present. See: http://www.fire.tc.faa.gov/pdf/07-57.pdf for the FAA report on 787 composite flam tests.

Back at NH 13th July 2013 14:00

BBC News web site

Ethiopian Airlines took delivery of four Dreamliners in 2012.
The company said its plane had been parked at Heathrow for eight hours before smoke was spotted.
"We have not grounded any of our aircraft," the carrier said in a statement.
"The incident at Heathrow happened while the plane was on the ground... and was not related to flight safety."

G-CPTN 13th July 2013 14:04

Fit sprinklers.

G-CPTN 13th July 2013 14:07


"The incident at Heathrow happened while the plane was on the ground... and was not related to flight safety."
Well, they would say that, wouldn't they?

Carefully-worded PR statement.

cappt 13th July 2013 14:12

External power provided by the jetway is AC not DC. Most modern jets have a service mode on the external electrical control panel for when the aircraft is left unattended, this is so cleaners have lights etc. Yes some galley items are on the service bus on the plane I fly such as water line heaters and coffee pots.

aeromech3 13th July 2013 14:24

Ref to MilktrayUK and the Boeing Doc, I find it strange that Boeing place the GP receptacle on the LH side, mostly they are found RH or centre and as the vehicle plan shows a GPU on the RH side, there must be extra long cables.
Perhaps Hi_Tech could qualify whether similar to other Boeings the GP can be on a service mode to allow cargo door/loading and limited galley power for start up of coolers and of course to get the kettle (rapid boiler) on for the Capt. tea.
I found it distressing to watch on tv, a 'Fireman' climb a ladder at the aft cargo door, mostly unsupported and attempt to unlock, by over-reaching, the door; this raises the question in my mind as to their knowledge of modern airliners if power was not on-line. Also not good was to see so many Firemen standing around with what appears very little direction when the airport could have been made operational earlier by their return to standby.

overstress 13th July 2013 14:44

From Boeing's website


The 787-8 airplane utilizes two forward ground power receptacles and one mid-aft ground power receptacle. Receptacle ground heights are minimum 81 inches (206 centimeters) and maximum 108 inches (274 centimeters). Each receptacle is rated at 90 kilovolt amperes (KVA), the same as other Boeing twin-aisle production airplanes.

Similar to existing airplanes, the 787 utilizes power from the auxiliary power unit (APU) for engine start. The 787 is different in that it uses electrical power for engine start rather than the pneumatic power used on existing airplanes. If the APU is inoperative, an engine start can be performed using a minimum of two 90 KVA external ground power units (GPUs). Boeing recommends the use of three 90 KVA ground power sources to decrease engine start times and minimize ramp impact during ground operations. Same as the 777 and other twin-aisle airplanes, the ground power requirements must conform to the electrical power quality requirements specified in figure 5.
Why unusual to put GP on LHS? GP often comes from the jetway after all.

MilktrayUK 13th July 2013 14:45


Ref to MilktrayUK and the Boeing Doc, I find it strange that Boeing place the GP receptacle on the LH side, mostly they are found RH or centre and as the vehicle plan shows a GPU on the RH side, there must be extra long cables.
I have edited my earlier post, with a photo. You are correct that on narrow bodied aircraft, this connector would be on the LH. For wide bodied aircraft, one connector cannot supply enough power for the full electrical loads. Calculating the length of cables and power losses for each aircraft model using the stand would be part of the stand design process for a fixed installation!

I should add that the system includes a feedback mechanism controlled by the aircraft, so the supply is de-energised if the load is dropped by he aircraft electrical system. The common on-line reference sites do not describe systems for fixed installations, or list relevant photos. System descriptions can be found on supplier websites.

For starting the 787 engines with the APU unserviceable, a third GPU is recommended. This connection is located behind the wing, serving the aft electrical bay, where the main generator feeds connect into the power system. Most likely a diesel power cart would be used in that scenario, but I do wonder about the operational procedures needed with ground staff working behind running power plants and main gear.:hmm:

gcal 13th July 2013 14:46

Parts and the quality of will IMHO be the answer here.
It really will be as simple as that.

overstress 13th July 2013 14:52


For starting the 787 engines with the APU unserviceable, a third GPU is recommended.
But not compulsory. It's all covered here: AERO - Preparing Ramp Operations for the 787-8

Eclectic 13th July 2013 14:57

Ethiopian Airlines "statement" and more: Ethopian Airlines Releases Statement On Smoldering Dreamliner; UTX Climate System Implicated In Fire | Zero Hedge

Agaricus bisporus 13th July 2013 15:22

Eclectic, thanks for posting a worthless link to a shameless urban rumour/scandalmongering site that adds precisely nothing to the debate, rather sets it back.

Fail.

SLF-Flyer 13th July 2013 15:28

Sorry this is off topic, I just wish people with no knowledge would keep their fingers off the keyboard.


How wrong can you be NAROBS. As someone who maintained a large building in London I can tell you how fire cover works.
Buildings are graded by the fire services, in my case the building was called a section 20. This required high temperature detectors in non-operational areas and a 24 hour cover by my staff. If a temperature alarm went off it had to be investigated and the fire services called if a fire was found.

This arrangement led to an embarrassing episode. One night in the early hours an alarm went off, two staff went to investigate. One was a rugby player the other one could handle himself. When they opened the door to the room with the alarm, they were jumped on and a fight took place. The end result was Building Maintenance 1 – 0 Met Police. The police had been given a heater to keep themselves warm, yes they had it under a temperature detector. The police were using the higher floors of the building a watch tower.


Personally I think the airport authorities acted correctly in closing the airport. If most units had been called out to two suspect fires, they had no option but to stop all aircraft movements.

Back door 13th July 2013 15:36

787 issues
 
what ever the fault turns out to be, you can imagine the PR staff at Boeing is working overtime. But realistically mr joe public will forget about this with one click of the mouse and on to the next news headline. The NTSB might be a different story........

Bigpants 13th July 2013 16:01

Damage Limitation
 
Rather than talk about what has happened let me predict Boeings next move.

They will pressure their own engineers to apply a temporary fix to what is possibly a write off.

They will then fly it unpressurised somewhere very quiet and re build it in a secure hangar using all resources regardless of cost.

The FAA will not ground it again and the spin machine will distract us with more PR while engineering goes round the world applying yet another fix to customer aircraft.

All will be well until the next fire happens.

Burnie5204 13th July 2013 16:08


Most likely a diesel power cart would be used in that scenario, but I do wonder about the operational procedures needed with ground staff working behind running power plants and main gear
No different to a current ASU start protocol. They dont work behind any running plant.


If connection is on LHS (as in this case) then the connection (pneumo or elec) is made, chocks (Nose and LHS) remain in.
Ground crew withdraw
No2 engine (i.e. RHS) is started,
Crew move back in to remove connections and chocks
Aircraft pushed back
Other engine(s) started by cross-bleed (or using elec from the No2 generators in this case).

The crew aren't working behind any running plant but on the opposite side of the aircraft body.

kuningan 13th July 2013 16:44

BBC reporting:

BBC News - Batteries 'not linked' to 787 fire

In fairness, most of the MSM reporting I have seen has been pretty good - its tended to be 'Too early to tell, batteries have been a problem in the past - but we don't know its the case here'

DarrenWheeler 13th July 2013 17:07

AAIB press release

http://www.aaib.gov.uk/cms_resources...%20Release.pdf

JW411 13th July 2013 17:08

Please be gentle with me; I only flew professionally for the best part of half a century. I admit to being a reasonable pilot and operator but I never really did understand advanced "wiggly amps" (despite flying the Short Belfast for 6 years).

Now, I think I have got my head around the fact that the 787 has (had) a great deal of trouble with lithium batteries. (During my career I had a ni-cad battery blow up one night over Northern Kenya which then involved us in an emergency descent).

So, after a very expensive grounding, the 787 has been cleared to fly again (because they have now encased the suspect batteries inside an indestructable titanium box).

Have they actually solved the problem?

Now we have an incident that managed to close Heathrow for a couple of hours because all the fire engines were required to attend a fire on board a 787 which was being prepared for towing to the gate to go flying.

We are expected by some to celebrate the fact that the batteries had nothing to do with the fire in the galley that burnt a hole or two through the roof and some are indeed celebrating this as a source of vindication.

Could someone just explain to me, in very simple terms, how it is that one of the girls forgets to switch off one of the hot cups and eight hours later, when the aircraft is powered up to be towed to the gate, the amazingly modern electrical system in the 787 allows the aircraft to become a potential write off (melt down even) to say nothing of the expense of closing Heathrow for an hour or two.

It seems to me (as a stupid pilot) that such a complex aircraft should be able to survive the possibility of a hot cup left on or even a handbag left in one of the ovens by one of the girls. Just how far have we come?

Perhaps someone could make a fortune by selling the designers of the 787 electrical system a supply of RCCBs and some 13 amp fuses.

Perhaps the whole aeroplane is too clever for its own good.

I certainly will not get in one for a very long time.


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