Pilot’s Explanation – What’s really behind the Boeing 737 Max 8 issues
Bottom Line:Throughout the week the I’ve been in touch with a listener who also happens to be one of the pilots of the, now grounded, 737 Max 8 planes. From the onset he indicated that he believed this was a training issue, not a mechanical failure or malfunction of some sort. He indicated that in these planes there’s a system that is unique to this aircraft, that if pilots didn’t fully grasp, could result in the issues we’ve now had occur twice. Much of what he sent me was highly technical and candidly over my head but yesterday he sent this breakout of the new system/technology in play in these aircraft that’s as straight forward as he could make it:
MCAS (MANEUVER CHARACTERISTICS AUGMENTATION SYSTEM)
What it does:
- Commands a “Nose Down” elevator movement under the following conditions:
- Autopilot not engaged
- Flaps “Up”
- Near “STALL” speed
- Steep Turn
When:
- Aircraft “Nose Up Attitude” exceeds a predetermined threshold based upon aircraft altitude and airspeed
- MCAS receives data from multiple aircraft sensors
How:
- The Flight Control Computer commands the elevator “Nose Down”
(Can occur multiple times after pilots recover from the nose down attitude)
Corrective Action:
- Return aircraft attitude below the predetermined threshold (?)
Corrective action when MCAS continues to apply “Nose Down Force”:
- Stabilizer Trim Cutout Switches “immediately” to CUTOUT
The issue with the two Boeing crashes likely came down to this system kicking in and pilots no knowing how to handle the situation in time. It also appears as though Boeing likely under emphasized the need for comprehensive training of this new system when rolling it out in an effort to achieve more adaptation quicker by airlines.