ATSB Sends Garuda Crash Black Boxes to the USA

Even though the Flight Data Recorder (FDR) was apparently more damaged than the cockpit voice recorder (CVR), only the FDR had yielded information on the events leading up to the Garuda 737-400 Flight GA200 crash on March 7th that killed 22 people of the 140 onboard. Australian Transport Safety Bureau Deputy Director Joe Hattley said: "We have tried every method we can to download the cockpit voice recorder - but without success and that includes indepth consultation with the component manufacturer Honeywell in the U.S.".

However raw data yielded by the FDR had been sent to the Indonesian KNKT (NTSB equivalent) without any analysis. The bureau's executive director, Kym Bills, said it was up to Indonesian investigators to assess the data decoded so far. "It's more of a matter of checking it against the physical evidence and the other evidence that they've gathered on the accident site and in relation to the whole investigation," Bills said.

From what is known to date, it is suspected that the first officer (flying the approach), had allowed the aircraft to get too high on glideslope, flared high, then after touching down hard about 850m's into the 2200m runway, bounced three times and then latterly tried to go round - although the other pilot had been simultaneously attempting manual wheel-braking. The buffeting on finals (remarked upon by the Australian-Italian journalist onboard) is a known characteristic and thus had likely been caused by a non-recommended use of speedbrakes with 30 degrees of flap - in an attempt to burn off the excess height. Elevator effectiveness is known to be affected by speedbrake extension at any flap deflection, so they are usually stowed by no later than 500ft AGL (at which height the approach should be stabilized or a go-round commenced).

After flaring too high (because of the speedbrake) with auto-throttle still selected (i.e. and it not being cancelled no lower than 100ft AGL - per standard operating procedure), the autothrottle would have cut in at any height above 27ft RA (radar altimeter). This would have caused power to be added to maintain bug-speed and resulted in the aircraft floating well down the runway. In fact, at 400 feet RA and below, autothrottle is placed in a rapid engine acceleration range. According to the journalist, the speedbrakes were left out throughout - even whilst the aircraft bounced after being forced down to the runway by lowering the nose (i.e. in a yoke control input opposite to the usual backstick hold-off for the flare and sink onto the runway - as the speed dissipates naturally at idle throttle).

In previous coverage (link) aviationtoday has made mention of the on-ground PIO (pilot induced oscillation) known as porpoising. During the third porpoise, the nosewheel-first landing at high speed caused the nosewheels to detach and the photographic scrape evidence for that is to be clearly seen at this link.

During the very late attempted go-round, the aircraft had struck the adjacent embankment beyond the departure threshold. Damage to that (i.e. on the runway side of the road) was major, the center divider of the road it went across is reported intact and unmarked, and the opposite embankment (across the road) is minimally damaged. i.e. the aircraft was airborne and floating by the time it crossed the road, but never made it into positive rate. Evidence for the attempted late go-round is the final (at rest) trailing-edge flap deflection of 15 degrees and the wreckage distribution. It was also disclosed yesterday that the aircraft's port engine reverser had been locked out due to a reported sluggish operation the day before. It's uncertain, from what is known thus far, whether reverse was ever selected.

The accident appears to bear marked similarities to the indecisive events leading to an overrun in heavy rain at Bangkok by a QANTAS 747 in September 1999. Garuda Flt 200's accident was in fine weather and very light winds however.