The airspeed of the doomed Asiana Airlines Boeing 777-200ER fell to just 103kt at its slowest on the aircraft's ill-fated descent into San Francisco International airport according to information gleaned from the wrecked twinjet's flight data recorder.
Deborah Hersman, chairman of the US National Transportation Safety Board, told an 8 July press conference in San Francisco that the aircraft was travelleing at 106kt (196km/h) at time of the crash. However, around three seconds prior to impact, the aircraft reached its lowest speed of 103kt with its engines at about 50% power, although thrust was increasing. Investigations have concluded that both engines were functioning normally, says Hersman.
The aircraft's autopilot was disengaged at about 1,600ft (488m), 82s prior to impact, the flight data recorder shows. Around 73s before the crash, as it passed through 1,400ft, the twinjet had slowed to 170kt and it continued to lose speed on the descent, falling to 149kt at 1,000ft, 134kt at 500ft and 118kt at 200ft.
Thrust was applied as the 777 reached 125ft, with an airspeed of 112kt, 8s prior to the crash, says Hersman.
NTSB had previously confirmed that the pilots were flying below their target approach speed and had attempted a go-around 1.5s before impact. Data from the cockpit voice recorder indicates that a member of the flightcrew had called to increase speed about 7s prior to the incident.
Hersman reiterated that the jet was travelling "significantly slower" than it should have been. "137kt is the speed that they want to have when they cross the threshold of the runway," she says.
The crew of flight 214 were "vectored in" from the Northern California terminal radar approach control facility (TRACON) in Sacramento, for a "17 mile, straight-in, final visual approach," says Hersman.
NTSB confirms that it is conducting interviews today with the four pilots on board the aircraft during the 10.5h flight from Seoul's Incheon airport to learn more about the events leading up to the crash.
One of the pilots flying was working on his rating for the Boeing 777 and gaining initial operating experience for the type during the flight alongside a training captain, the NTSB confirms. There was another captain and first officer on board to provide relief during the flight.
NTSB plans to hold another press conference on 9 July in which it hopes to disclose more information about the pilots gathered from the interviews.
Asiana sasy that the pilot in charge of landing the twinjet was new to the 777 and had only accumulated 43h on the type, yet had 9,793h on Boeing 737, 747 and Airbus A320 aircraft.
Hersman also confirms that salvage crews have discovered some of the 777's wreckage has settled in the San Francisco Bay or is lodged in the sea wall separating runway 28L from the water.
"The lower portion of the tail cone is in the rocks at the sea wall," says Hersman. "There was a significant piece of the tail of the aircraft that was in the water."
Additional wreckage could be seen during low tide in the water as well, she says.
The debris field ran from the sea wall to several hundred feet up the runway. At the beginning of the pavement, horizontal stabilisers, vertical stabilisers and the upper portion of the tail cone could be seen, and proceeding towards the runway were parts of the main landing gear, and then the aft fuselage. "Witness marks" and scars on the asphalt are visible from the impact of the landing gear, engines and the fuselage.
Post-mortem examinations are ongoing to clarify the cause of death for one of the two passengers killed in the accident. The NTSB confirms that the two victims were sitting in seats toward the rear of the aircraft, which suffered significant structural damage.
In response to reports that an emergency response vehicle may have run over one of the victims, Hersman says "we are still looking at the issue, it is a very serious issue and we want to understand it".
Source: Air Transport Intelligence news
