In TAM and LH cases, pilots were locked out of using full braking capabilities of the aircraft because they found themselves in a situation that didn't satisfy the conditions defined as "landing" by aircraft designers. The had wheels on the ground, but program logic evaluated to onground = FALSE.
Westjet and Turkish incidents are irrelevant. Westjet malfunctioned, pilot took control and landed safely - that's what pilots are there for. Turkish airplane also malfunctioned and gave multiple warnings over several minutes, but pilots didn't pay attention to what the aircraft was doing until stall warning activated at 460 feet, by which time it was too late. Had they paid attention, they would've also recovered and landed safely.
In contrast, Airbuses systems didn't malfunction. They worked as designed and made the already difficult situation (landing in bad weather) deadly due to not responding like a pilot would expect. The design was deeply flawed, just like MCAS.
The had wheels on the ground, but program logic evaluated to onground = FALSE.
Nope. The Lufthansa bird had one bogie on the ground and one off. With the TAM flight the pilots left one thrust lever at climb power and one at idle, pure pilot error.
The Westjet and Turkish incidents are irrelevant. Westjet malfunctioned, pilot took control and landed safely - that's what pilots are there for. Turkish airplane also malfunctioned and gave multiple warnings over several minutes, but pilots didn't pay attention to what the aircraft was doing until stall warning activated at 460 feet, by which time it was too late. Had they paid attention, they would've also recovered and landed safely.
Unfortunately the 737s were functioning as designed, the computers took invalid input and ran with it instead of cross checking it.
> Nope. The Lufthansa bird had one bogie on the ground and one off.
Which is to be expected from a crosswind landing (especially with a lot of lift from higher-than-usual speed), but it took 900 m of runway before enough weight was detected on both of them to activate thrust reversers and spoilers. And even after all wheels were on the ground, it took another 300 m before wheel brakes became active. The accident investigation report recommended introduction of emergency override to cover the whole range of conditions in which airplanes fly.
> With the TAM flight the pilots left one thrust lever at climb power and one at idle, pure pilot error.
The aircraft was firmly on the ground, with one thrust lever in reverse position. Spoilers and auto-brake did not activate because position of the other lever lever was prioritized over actual condition of the aircraft. Critical data was derived from a thrust lever, which has no safety features to prevent inadvertent wrong positioning. Furthermore, lever positioning suppressed aural reminders to bring thrust levers to idle (the famous "RETARD").
> Unfortunately the 737s were functioning as designed, the computers took invalid input and ran with it instead of cross checking it.
Which is irrelevant on the 737, because its design philosophy expects pilots to monitor and (if necessary) override automation, which hundreds of attentive crews successfully did before the Turkish crash. A320, on the other hand, lacks emergency override, as the LH2904 investigators noted in their report. It cannot reliably tell whether the aircraft is on the ground or not, and stops pilots from taking the correct action.
Westjet and Turkish incidents are irrelevant. Westjet malfunctioned, pilot took control and landed safely - that's what pilots are there for. Turkish airplane also malfunctioned and gave multiple warnings over several minutes, but pilots didn't pay attention to what the aircraft was doing until stall warning activated at 460 feet, by which time it was too late. Had they paid attention, they would've also recovered and landed safely.
In contrast, Airbuses systems didn't malfunction. They worked as designed and made the already difficult situation (landing in bad weather) deadly due to not responding like a pilot would expect. The design was deeply flawed, just like MCAS.