JammedStab
11th Oct 2013, 12:22
It is still only in French on the BEA website. Years ago, they actually mailed me an English version.
I finally found an English copy on the web located here.
http://lessonslearned.faa.gov/AirFrance747/accident_report.pdf
The translation makes it a bit difficult to understand at times but it seems that the VNAV Path levelled them off and advanced thrust at the End of descent point in the FMC which is likely close to the MDA.
The manuals said that autopilot and autothrottle are to be disconnected at the MDA. In this case the autopilot had been disconnected 10 miles back and only the autothrottle was being used for approach. It was not disconnected in a timely manner as recommended and this resulted in them becoming high and fast due to engine power automatically increasing. This was manually overridden with thrust levers held closed until touchdown, 20 knots fast and 2700 feet down the runway.
In fact, it appears that the autothrottle was never disconnected prior to touchdown(pilot stated that he was unable to disconnect the auto-throttle) and therefore near or after touchdown, an outboard engine went to high power as the PF`s hand was maneuvered for selecting reverse thrust. Because of thrust lever not being in idle, there was no autobraking or spoiler activation. The aircraft did slow down despite the outboard engine still at high thrust which eventually caused a lateral runway excursion.
According to the FAA website "As a result of this accident, Boeing modified the automatic flight system logic for non-precision approaches to more closely reflect the VNAV mode performance employed in precision approaches, and made the system upgrade available to the operational fleet."
I finally found an English copy on the web located here.
http://lessonslearned.faa.gov/AirFrance747/accident_report.pdf
The translation makes it a bit difficult to understand at times but it seems that the VNAV Path levelled them off and advanced thrust at the End of descent point in the FMC which is likely close to the MDA.
The manuals said that autopilot and autothrottle are to be disconnected at the MDA. In this case the autopilot had been disconnected 10 miles back and only the autothrottle was being used for approach. It was not disconnected in a timely manner as recommended and this resulted in them becoming high and fast due to engine power automatically increasing. This was manually overridden with thrust levers held closed until touchdown, 20 knots fast and 2700 feet down the runway.
In fact, it appears that the autothrottle was never disconnected prior to touchdown(pilot stated that he was unable to disconnect the auto-throttle) and therefore near or after touchdown, an outboard engine went to high power as the PF`s hand was maneuvered for selecting reverse thrust. Because of thrust lever not being in idle, there was no autobraking or spoiler activation. The aircraft did slow down despite the outboard engine still at high thrust which eventually caused a lateral runway excursion.
According to the FAA website "As a result of this accident, Boeing modified the automatic flight system logic for non-precision approaches to more closely reflect the VNAV mode performance employed in precision approaches, and made the system upgrade available to the operational fleet."