It is just over a week since the TAM Airbus A320 accident at Sao Paulo Congonhas.
Although various official statements - including some based on flight data recorder (FDR) downloads - have been released, it is still difficult to understand exactly what was going on to make this accident happen in the way it did.
The confirmation yesterday by the head of Brazilian accident investigation agency CENIPA Brigadier Jorge Kersul Filho that the aircraft was travelling at 94kt when it hit the TAM Express building felt like a physical shock, although it should not have been a surprise given the mass of disparate information available. And there is a mass of information out there.
Video footage from a fixed security camera at the airport terminal showed the doomed A320 entering the frame from the right at a higher speed than other aircraft landing before it, but that was not the most significant thing it showed. It was the fact that it was failing to slow down that was puzzling. Kersul says the aircraft touched down at the recommended speed, so when it entered the video frame travelling fast it was not because of a high speed landing.
CENIPA has cleared Airbus to release some FDR-deduced detail to operators. The most significant part of the advice is this: "During the flare at thrust reduction select ALL [sic] thrust levers to IDLE [sic]." After a statement like that, approved by CENIPA, it is not necessary to speculate about whether the pilot flying left at least one throttle lever open; it cannot mean anything else. Among the remaining questions are: how much power was left on? For how long during the landing run? And did the pilots realise what the problem was? With a throttle lever open, the spoilers would not deploy on touchdown.
Strictly speaking it would be speculation to say that this aeroplane, landing on an ungrooved wet runway with no spoiler deployment, would aquaplane. But it probably did. Although the performance figures for an A320 at this aircraft’s landing weight show that it could land safely on Congonhas 35L under the prevailing conditions with everything working as it should, all operators based there know that there is not much room for error. So if error or failure does occur, go-around is the only option. The more difficult part is to recognise a mistake or a failure quickly, identify it correctly, and act accordingly. That frequently proves to be a tall order for human beings when what is happening is not what they expected.
So did the crew attempt a go-around? We will soon know for certain, but it looks like it. If the aircraft hit the TAM Express building at 94kt, when it left the runway end it would have been travelling about 100kt. By that time the crew would already have known for many long seconds that stopping on runway had become absolutely impossible. Meanwhile take a look, as many have already done, at the photograph showing the wheel tracks in the grass to the left of runway 35R’s far end, where the aircraft deviated off the tarmac just before vaulting over the wide Avenue Washington Luis the other side of the airfield boundary: the mainwheel tracks are there, but the nosewheel track is not. At 100kt it would be natural to lift the nose hoping to fly, even when you know you can’t.