Originally Posted by
Bend alot
However, retracting the flaps could (regardless of risk level) allow the aircraft to be flown in a condition that is known not to be certifiable.
One would expect that the aircraft could not be certified (?) with flaps retracted.
I think this will be the sticking point, the aircraft NEEDS MCAS, the fix has introduced many ways to limit and deactivate MCAS.
Nothing has changed, only the thing that is required is often not available anymore.
It is not just a case of the aircraft is safe to fly, but it must fly like it's little brother, in every part of the envelope all the time - and it can not do this without an active MCAS.
I think for certification it needs a fail safe system that keeps MCAS alive or very low probability of being shut down.
The fix is to remove MCAS basically! When we can all see by the data that it operated exactly as it was told (designed) to do - MCAS never made an error! 3 inputs would be a clever option.
I hear what you're saying, but let me try this again with a simple example.
To be certifiable (and more to my way of thinking, cleared for dispatch) the 737 needs two functioning Inertial Reference Units (IRU). During the flight, let's say one of the IRU's fail. At this point, the aircraft is no longer "certifiable." However, I'm already in the air, so I pull out the appropriate non-normal checklist (which is quite involved), and let's say I am unable to reset the unit. I will then throw a switch to put both sides on a single IRU and continue to destination under certain additional restrictions. Once the plane is on the ground, it will stay on the ground until the faulty IRU is fixed or replaced. The same logic can be applied to numerous aircraft systems, not just the MCAS.
Every system on the aircraft is subject to failure, and some of those failures will put the aircraft out of its certifiable limit. The manufacturer does not eliminate those systems, but rather they develop non-normal procedures to deal with the failure until the aircraft is on the ground and the system can be repaired. This is the way it has been done in aviation since before I took my first flight.
There are certain components (like the wing) that really do fall in a fail-safe category, and they necessarily meet a much a higher standard. MCAS is not one of those items.