Aircraft News Weblog

Tag: 777

  • Asiana Airlines Boeing 777 crash at San Francisco

    There is a lot of information and conjecture coming out in the press regarding the reason the Boeing 777 hit the sea wall during the attempted landing at San Francisco. There will be a definite answer from the NTSB when the investigation is completed which could take months to finalize. Regardless of any mechanical or electronic failures in the aircraft that may have contributed to the crash, the investigation will consider the Human Factors involved. There are always human factors involved and they go well beyond the crew and the circumstances of this particular flight.

    The NTSB will construct a timeline for each crew member going back at least 72 hours. This will include all rest and work periods, medications or personal events which could influence concentration or mood. Crew interaction will be examined to ensure the appropriate actions were not affected by personalities in the cockpit. There will be an examination of the distractions and circumstances in regard to the approach into the airport, and also any distraction warnings or unusual circumstances within the aircraft during the flight.

    It seems to be common knowledge that there was training taking place in the cockpit during the flight. Training of the ‘pilot flying’ during the approach to San Francisco will be examined to assess the amount of supervision provided by the training Captain. This is particularly important as the responsibility to maintain the safety parameters lies with the training Captain if there is a departure from Standard Operating Procedures or erosion of safety limits.

    The reasons for this crash will be many and varied as the Human Factors reach into all aspects of the Asiana Airlines operation of the aircraft in their fleet. The reason could cross all types of aircraft and operations so lessons will be learned and changes and improvements made to prevent this type of accident occurring again in all airlines and operators.

  • Boeing 777 Trent engine problems with ice.

    The US Federal Aviation Authority have now issued an Airworthiness Directive (AD) concerning the problems with ice in the fuel system of Boeing 777-200 and 300 airplanes fitted with Rolls Royce Trent 800 engines. The AD requires the crew to monitor the fuel temperature within 3 hours of top of descent and if it is below a certain temperature they must increase the engine power to prevent the formation of ice in the main tank fuel supply system. They can do this by stepping up to a higher altitude or increase the airspeed. There is no requirement to carry out this procedure if the aircraft is not fitted with Trent 800 engines.

    There is also a procedure for the circulation of the fuel on the ground by a certified mechanic to prevent the formation of ice.

    This AD is a result of the problems encountered in January 2008 by a British Airways Boeing 777 which failed to respond to a command for increased thrust while the aircraft was on approach to London Heathrow airport and landed short of the runway. The interim report suggested ice formed in the main fuel tank supply system during low fuel flow conditions in cruise flight. The ice then dislodged and caused a restriction in the fuel supply because of high flow conditions due to the lower altitude during approach.

    No doubt there will be more measures to prevent the formation of ice from the engine and aircraft manufacturers but in the mean time the FAA are counting on this procedure to prevent the recurrence of the fuel restriction and loss of engine power.