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The purpose of MCAS was precisely that it didn't change procedure. There was already an existing procedure for runaway trim control. In the case of the Lion Air
by 0xffff2 8y ago
The purpose of MCAS was precisely that it didn't change procedure. There was already an existing procedure for runaway trim control. In the case of the Lion Air crash at least, applying that existing procedure would have allowed the pilots to fly the plane normally, albeit without the benefit of automatic trim. For reasons we will never fully know, the pilots did not apply that existing non-MAX specific procedure.
- SiempreViernes 8y agoThe very likely reason they didn't follow that procedure is that they didn't recognise the failure as runaway trim, which in turn is likely related to the apparent fact they didn't know MCAS existed. So couldn't know that the behaviour they experienced was what MCAS runaway trim felt like.
- 0xffff2 8y agoI don't think it's wise to speculate, but the stabilizer is coupled to a very large trim wheel in the cockpit that both audibly clicks as it spins and is market with white stripes (on a black wheel) to make the movement apparent. It's possible the pilots didn't realize what was happening, but it's not as if MCAS was silently causing a runaway.