Boeing delays 737 MAX software fix delivery

Re:Boeing delays 737 MAX software fix delivery by ams6110 on Tuesday April 02, 2019 @05:08PM (#19558607)

I'm not blaming no one else. The MCAS implementation was clearly flawed, being vulnerable to a single point of failure in the AoA data (and by the way, that's where the real problem lies. Why is the MAX AoA system failing more than the prior generation of 737 where it's normally totally reliable?)

But here's the thing. It's impossible to train or have a checklist for every eventuality or combination of failures. In the end, it's up to the pilots to use good airmanship and fly the plane. If systems are interfering with that, disable them and fly the plane. Trim system doing something you don't want? Disable it and fly the plane. Instruments disagree? Set known good pitch and power and fly the plane. It was daylight in good weather. Look out the window. Fly the plane. Diagnostics can wait until the plane is flying again.

Those two aircraft were flyable. All they needed to do was flip a switch. And fly the plane.

I'm not in any way suggesting that the problems with MCAS or AoA data on the 737 MAX should not be fixed.

[ Parent | on HN ]

Re:Boeing delays 737 MAX software fix delivery by linuxftw on Tuesday April 02, 2019 @06:46PM (#19559307)

> The MCAS implementation was clearly flawed, being vulnerable to a single point of failure in the AoA data

I personally find the AoA sensors failure to be unlikely in the case of the Lion Air crash as they were replaced in between the two problematic flights.

I most interested in seeing the final results of the Ethiopian crash. My suspicion is the MCAS has terrible software and is a bug-ridden mess.

[ Parent | on HN ]

Re:Boeing delays 737 MAX software fix delivery by salawat on Wednesday April 03, 2019 @11:17AM (#19564035)

Ah, but the flight computer switches which AoA sensor it talks to every time it's booted.

If maintenance procedures for testing did not correctly specify that a retest must start, then restart the system to actually test that the repair was successful, then that replacement may have been tested while the computer was being fed data by the correctly operating sensor. They would have had to attempted a single boot between flights for the next flight to have flown with the untested replacement sensor. If they didn't test at all, then it's possible both sensors had a problem.

This is of course assuming that there is any retest procedure at all in the documentation given that the AoA sensor wasn't classified as safety-critical.

It really seems like the makings of a bad movie doesn't it?

[ Parent | on HN ]

Re:Boeing delays 737 MAX software fix delivery by inferiorhuman on Wednesday April 03, 2019 @12:16AM (#19560675)

In the end, it's up to the pilots to use good airmanship and fly the plane

That's why it's incumbent upon Boeing to let the pilots know about all of the systems.

Trim system doing something you don't want?

STS generally does this by design.

Disable it and fly the plane

Boeing claims that MCAS is a part of STS. Well, you can disable STS quite easily by pushing/pulling on the yoke. You cannot disable MCAS this way.

[ Parent | on HN ]