Leaked Detailed BA 777 Accident Investigation Update

Allegedly leaked information and photos on the PilotsofAmerica.com forum. Very interesting stuff here if it’s confirmed.

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At about 700 ft AGL, the auto throttle commanded engine acceleration. One engine started to rollback during and the other engine started to accelerate then 8-10 seconds later began to roll back. Once the flight crew noticed, they pushed the throttles up and the engines’ EECs responded but the engines did not. It appears that no fuel was getting to the engines.

The investigation continues to look broadly for a cause of the dual engine rollbacks. Fuel exhaustion is the only item that has been positively ruled out. Aspects that the FAA believes the investigation is concentrating on are:

• Ice in the fuel somehow limiting the fuel flow to the engines. A maintenance 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, conducive to ice formation.

• 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 the fuel specification). Testing has been started looking for small particles (greater than 5 microns).

• Engine hardware failures sending inaccurate data to the engine electronic control (EEC) causing the EEC to demand insufficient fuel. A preliminary review of the EEC data from the right engine shows erratic combustor inlet pressure (P30). A leaking P30 sense line could cause this, or the EEC receiving a higher than actual fuel flow parameter.

• Software coding problem in the EEC causing the EEC to demand insufficient fuel. British Airways installed a new engine EEC software revision in 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 related to the accident: improvements to low power stall recovery logic and fan keep out zones for ground maintenance. The first two items would be related to a part 25 compliance issue, while the last two items would be related to a part 33 compliance issue.

MUCH MORE BELOW THE FOLDAs stated yesterday in this briefing paper, the electrical system anomalies noted earlier have been resolved, as describe below, and the conclusion now is that the electrical buses were powered until impact and performing as expected.

• The auxiliary power unit (APU) began its auto start sequence, even though the buses were still powered. In the days following the event, the flight 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 the impact for the APU inlet door to open, but not for the APU fuel pump to turn on or the APU engine to start spooling up.

• The quick access recorder (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 properly and was in the process of saving data when impact occurred, accounting for the “lost” 45 seconds of data.

• The fuel crossfeed valves were closed in flight according to the flight crew, but the switches were found in 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 crew now believes they opened the valves just prior to impact and the airplane lost power before both valves moved to the open position.

• The ram air turbine (RAT) was found deployed, even though the buses were still powered. It did not deploy until after the airplane came to a stop, as determined 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.

Fuel 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 fuel system hardware tomorrow.

Engines: Component testing and teardown of the engine-driven fuel pumps and the fuel metering units is planned for later this week. The data from the electronic engine controls is still being analyzed. Rolls-Royce is planning an engine test, unscheduled as yet, to try and duplicate the rollbacks.

Crashworthiness: Cabin crew and passenger questionnaires indicate that the evacuation bell was faint, but the evacuation light was seen and the captain’s 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 effective at the introduction of the Model 777 series airplanes require seats protect occupants for hard landing impact up to 35 ft/sec. The passenger with the broken leg was sitting next to the point where the right main landing gear punctured the fuselage and pushed into the cabin (pictured below).

Crashworthiness: There was only one serious injury, a compound fracture to the leg. The airplane landed on the main gear, bounced, came back down on the gear, then the gear failed, and the engines supported weight of the airplane. 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. The report of a fuel leak is unconfirmed. All the slides deployed and the doors 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 oxygen masks dropped.

*Surprised by what you have read?Do you think this report has gone any closer to establishing the true reason for the crash? Have youir say on AirSpace

12 Responses to Leaked Detailed BA 777 Accident Investigation Update

  1. chris lee February 1, 2008 at 7:33 am #

    Here’s a far out theory:

    Ever heard of gadgets called “cellphone disruptors”? They’re used by the military to either prevent bomb attacks or cause them to explode prematurely. They’re in heavy use in Afghanistan and Iraq, they are also used to protect embassies. They provide a ‘dead zone’ about 600 – 800m radius. They are also used for VIP convoy protection – the sort of thing, for instance, that Gordon Brown (UK Prime Minister) might have as he drove to the airport.

    See where I’m coming from? Far out as it is, it does explain two of the mystery issues very nicely i) why it’s never happened before, ii) why it affected both engines not quite simultaneously. If correct, the investigators will find no evidence of defect with the aircraft.

    Anyone know if the UK Prime Minister had any such protection, or other ECM? If not, it’ll blow the theory out of the water. But if the convoy was protected . . . well, think about it from the VIP convoy commanders point of view. He flicks the switch on the black box, and lo, a 300 tonne airliner with an unblemished record a decade long has a two engine failures and nearly lands on his head. Coincidence?

  2. Bubba February 1, 2008 at 6:54 pm #

    Chinese fuel probably had lead in it, like their toys.

  3. Peter P February 1, 2008 at 8:39 pm #

    I worked in the Avionics Industry for nearly a decade. The theory is not preposterous. In service, grounding of shields always presents issues, with movement in pins, buildup of contamination on pins and under bonding straps etc. It doesnt have to be EM energy received through the shielded cable. It can be the sensors themselves that may be susceptible. Rather than a “cell phone disruptor”, it is possible that targeted focused high energy Microwave energy could be used to bring down a civil aircraft in these circumstances. The hole in the theory in this instance is that the engines should have resumed normal operation as the aircraft moved away from or descended out of line-of-sight of the attacker. The change in angles as the aircraft moved past the microwave attack would mean that depending on a continuous attack is unlikely to succeed. What could have occured is a burning out of a critical part of circuitry due to a burst of high energy microwave energy in a component not fully protected by shielding. For this theory to be correct the investigators will find evidence. There will be a burnt/non-functioning component(s) either in the engine sensors, or in the EEC. You would also expect interference with nav/comms equipment through antennas and this too should show on CVR or FDRs. For such an attack to have succeeded, the attackers would have to have been very lucky to have picked an aircraft that may have had a vulnerability due to imperfections in or maintenance of pins or wiring. Still, aim at enough aircraft, you may get lucky?

  4. Peter P February 1, 2008 at 8:52 pm #

    I worked in the Avionics Industry for nearly a decade. The theory is not preposterous. In service, grounding of shields always presents issues, with movement in pins, buildup of contamination on pins and under bonding straps etc. It doesnt have to be EM energy received through the shielded cable. It can be the sensors themselves that may be susceptible. Rather than a “cell phone disruptor”, it is possible that targeted focused high energy Microwave emission could be used to bring down a civil aircraft in these circumstances. The hole in the theory in this instance is that the engines should have resumed normal operation as the aircraft moved away from or descended out of line-of-sight of the attacker. The change in angles as the aircraft moved past the microwave attack would mean that depending on a continuous attack is unlikely to succeed. What could have occured is a burning out of a critical part of circuitry due to a burst of high energy microwave energy in a component not fully protected by shielding. For this theory to be correct the investigators will find evidence. There will be a burnt/non-functioning component(s) either in the engine sensors, or in the EEC. You would also expect interference with nav/comms equipment through antennas and this too should show on CVR or FDRs. For such an attack to have succeeded, the attackers would have to have been very lucky to have picked an aircraft that may have had a vulnerability due to imperfections in or maintenance of pins or wiring. Still, aim at enough aircraft, you may get lucky? (If you dont get caught first, as your emissions will surely attract attention quickly!)

  5. One Winglow February 5, 2008 at 6:29 am #

    After several weeks of investigation and no apparent reason for the ‘landing incident’ at Heathrow, I am amazed that the B777 is still allowed to fly. If that had been an Airbus I can just hear the screams for a grounding from our cousins across the water! I hope Boeing are not involved in this silence.
    Do we just wait for the next one to lose both engines?

  6. John February 9, 2008 at 11:47 pm #

    Fuel pump impeller blade edges most likely will reveal impact with ice if they are chipped and or scored.

    Should all 772s with RR engines be grounded until the root cause has been found?

  7. Tim Wood February 12, 2008 at 4:34 am #

    I just love all the loony theories after an accident. Don’t you all realise aircraft are incredibly complex and all your theories about cell phone disruptors or magic rays or whatever are just crap. As to “grounding” aircraft, why should we cancel many thousands of passengers trips and put thousands of airline employees out of work. Why? No one even was killed. Do you know what grounding an aircraft means. Can you imagine the litigation? Why don’t you suggest taking say all fast sports cars off the road because they’re dangerous? What is it about aviation that totally non technical “experts” come up with ridiculous theories about what happened and what the airlines should do? Just wait for the real experts, kiddies.

    Tim
    Licenced engineer, B747/4, B757, B767, B737, and many others.

  8. Mike February 12, 2008 at 4:14 pm #

    It’s taking too long to establish the root cause of this accident. Pump impeller blade damage from slicing thru ice in a fuel tank should be easy to establish. Duff software sending/receiving erroneous information should be fairly straightforward to establish.

    If the FAA had not grounded DC1Os because of a cracked fitting that held the pylon to the wing rear spar, (Chicago disaster) the potential for another similar disaster existed. More scored mount fittings were found, by the way.

    Keeping our fingers crossed that a big twin
    spools both up when commanded.

  9. Schulx February 18, 2008 at 6:10 am #

    I’m an aircraft engineer with a background in RCM and MSG-3; indeed, I have taught these subjects to CAA, Virgin and Cathay engineers. In all aircraft systems design a massive amount of effort is put into designing systems to eliminate all potential single point failures using tools like RCM, FMECA, Criticality and Fault Tree analysis. Consequently, to my simple mind, something has occurred that has introduced a single point failure where there wasn’t one before; the B-777 deserves its ETOPS clearances and these have been fully justified. The classic theory would point to some type of software issue that was insufficiently analysed or tested (and most real time software cannot be 100% tested). The water content in the fuel might be a potential single point failure but it would be unlikely to affect both engines at once, although there is evidence that they were not both in exactly the same failure condition. Maintenance errors can introduce the unknown, such as loose objects like swarf causing unpredictable short circuits etc. It was reported by the media that this aircraft had recently been to BA’s South Wales maintenance facility for a Check; I don’t know whether this is true or not, but if it is I would be interested to know what work was done there.

  10. Annis Koolman December 23, 2009 at 11:36 pm #

    Thank you for that informative post. I really love to read articles that have good information and

  11. Malena Bessinger February 8, 2010 at 7:10 pm #

    What is the best place for background checks that are not on the Internet?

  12. Jimmy Aubin December 19, 2010 at 7:15 pm #

    I bet you can’t find a site that really has unlimited background checks, other than Researchanyone.com, not unless you are using another site I know of. Seriously.