Re: Investigation Update

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Roger can you forward this article in a text form not
in html form. listserve messes it up that makes it
unreadable. from what i could gather, sounds like an
interesting stuff. 

--- Roger LaFrance <lafrance@xxxxxxxxxxx> wrote:

> Investigation Update=0AAllegedly leaked information
> and photos on the Pilot=
> sofAmerica.com forum. Very interesting stuff here if
> it's confirmed.=0A=0A=
> =0AAt about 700 ft AGL, the auto throttle commanded
> engine acceleration. On=
> e engine started to rollback during and the other
> engine started to acceler=
> ate then 8-10 seconds later began to roll back. Once
> the flight crew notice=
> d, they pushed the throttles up and the engines'
> EECs responded but the eng=
> ines did not. It appears that no fuel was getting to
> the engines. =0AThe in=
> vestigation continues to look broadly for a cause of
> the dual engine rollba=
> cks. Fuel exhaustion is the only item that has been
> positively ruled out. A=
> spects that the FAA believes the investigation is
> concentrating on are:=0A=
> =95 Ice in the fuel somehow limiting the fuel flow
> to the engines. A mainte=
> nance message indicating excessive water in the
> center tank was set during =
> taxi on the two previous flight legs, although it
> cleared itself both times=
> . The airplane was being operated in a high
> humidity, cold environment, con=
> ducive to ice formation.=0A=95 Small-sized
> contamination building up in the=
>  engine fuel systems somehow limited the fuel flow
> to engine. All the fuel =
> samples have tested for contamination of larger
> particles (sizes outside th=
> e fuel specification). Testing has been started
> looking for small particles=
>  (greater than 5 microns).=0A=95 Engine hardware
> failures sending inaccurat=
> e data to the engine electronic control (EEC)
> causing the EEC to demand ins=
> ufficient fuel. A preliminary review of the EEC data
> from the right engine =
> shows erratic combustor inlet pressure (P30). A
> leaking P30 sense line coul=
> d cause this, or the EEC receiving a higher than
> actual fuel flow parameter=
> .=0A=95 Software coding problem in the EEC causing
> the EEC to demand insuff=
> icient fuel. British Airways installed a new engine
> EEC software revision i=
> n December 2007. The software was approved in May
> 2006. There were several =
> changes to the software as part of the revision. Two
> items seem remotely re=
> lated to the accident: improvements to low power
> stall recovery logic and f=
> an keep out zones for ground maintenance. The first
> two items would be rela=
> ted to a part 25 compliance issue, while the last
> two items would be relate=
> d to a part 33 compliance issue.=0AMUCH MORE BELOW
> THE FOLD=0AAs stated yes=
> terday in this briefing paper, the electrical system
> anomalies noted earlie=
> r have been resolved, as describe below, and the
> conclusion now is that the=
>  electrical buses were powered until impact and
> performing as expected.=0A=
> =95 The auxiliary power unit (APU) began its auto
> start sequence, even thou=
> gh the buses were still powered. In the days
> following the event, the fligh=
> t crew has added additional details to their report.
> The crew now believes =
> they turned the APU on prior to impact. There was
> sufficient time before th=
> e impact for the APU inlet door to open, but not for
> the APU fuel pump to t=
> urn on or the APU engine to start spooling up.=0A=95
> The quick access recor=
> der (QAR) saved data and shut down approximately 45
> seconds prior to impact=
> . The QAR saves data in batches. It is believed the
> QAR was working properl=
> y and was in the process of saving data when impact
> occurred, accounting fo=
> r the =93lost=94 45 seconds of data.=0A=95 The fuel
> crossfeed valves were c=
> losed in flight according to the flight crew, but
> the switches were found i=
> n the open position and only one valve was open. In
> the days following the =
> event, the flight crew has added additional details
> to their report. The cr=
> ew now believes they opened the valves just prior to
> impact and the airplan=
> e lost power before both valves moved to the open
> position.=0A=95 The ram a=
> ir turbine (RAT) was found deployed, even though the
> buses were still power=
> ed. It did not deploy until after the airplane came
> to a stop, as determine=
> d by the pristine condition of the turbine blades.
> The RAT either deployed =
> due to electrical power loss during impact with a
> failed air/ground signal =
> or the impact unlatched the RAT door.=0AFuel system:
> Leads regarding water =
> in the fuel and fuel contamination are continuing to
> be investigated. Fuel =
> testing looking for small-sized contaminants (5
> microns) is beginning. The =
> tanks are still being drained and the team hopes to
> start evaluating the fu=
> el system hardware tomorrow.=0AEngines: Component
> testing and teardown of t=
> he engine-driven fuel pumps and the fuel metering
> units is planned for late=
> r this week. The data from the electronic engine
> controls is still being an=
> alyzed. Rolls-Royce is planning an engine test,
> unscheduled as yet, to try =
> and duplicate the rollbacks.=0ACrashworthiness:
> Cabin crew and passenger qu=
> estionnaires indicate that the evacuation bell was
> faint, but the evacuatio=
> n light was seen and the captain=92s message to
> evacuate over the passenger=
>  address system was heard. Preliminary data
> indicates that the descent rate=
>  at impact was roughly 30 ft/sec. Dynamic seat
> requirements that became eff=
> ective at the introduction of the Model 777 series
> airplanes require seats =
> protect occupants for hard landing impact up to 35
> ft/sec. The passenger wi=
> th the broken leg was sitting next to the point
> where the right main landin=
> g gear punctured the fuselage and pushed into the
> cabin (pictured below).=
> =0ACrashworthiness: There was only one serious
> injury, a compound fracture =
> to the leg. The airplane landed on the main gear,
> bounced, came back down o=
> n the gear, then the gear failed, and the engines
> supported weight of the a=
> irplane. The descent rate at landing was 1500-1800
> feet per minute. One of =
> the main landing gear swung around and pushed
> slightly into the cabin. The =
> other punctured the center fuel tank (empty) leaving
> a 1-by-2-foot hole. Th=
> e report of a fuel leak is unconfirmed. All the
> slides deployed and the doo=
> rs worked. Some passengers had to shuffle down the
> slides due to the slight=
>  angle. The flight deck door opened on its own
> during the landing. Some oxy=
> gen masks dropped. =0A*Surprised by what you have
> read?Do you think this re=
> port has gone any closer to establishing the true
> reason for the crash? Hav=
> e youir say on AirSpace=0ATags:=0A777 =0ABoeing
> =0ABritish Airways =0APoste=
> d by Jon Ostrower on January
> 
>
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