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Boeing 737 Max pilots complained to feds for months about suspected safety flaw

dallasnews.com

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Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#121

Post by dajohnson89 »

dpwm wrote: post #45
tuna-piano wrote: post #30

Some context: 1. There have been 865 737 related ASRS reports since 1/1/2018 2. I don't know how to quickly separate out 737-MAX reports from the non 737-MAX reports, as the ASRS database doesn't include 737-MAX as an airplane type! From scanning, I can say that there are more than five MAX related reports, though. [1] All 865 737 reports since 1/1/2018 CSV - http://s000.tinyupload.com/index.php?file_id=5466867979406…

regex? I just grepped "B737 max" and found 11 entries. "737.{0,20}max" (case insensitive) yields 20. [0] [0] CSV output: https://pastebin.com/87N023cx

So 20 MAX-related issues out of ~850. How is that significant?

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#122

Post by celticninja »

pdonis wrote: post #102
jashkenas wrote: post #53

Earlier quoted context omitted.

Great links! Here are the three 737-related ASRS reports that mention MCAS: ACN: 1597286 "Day 3 of 3 departing in a MAX 8 after a long overnight. I was well rested and had discussed the recent MAX 8 MCAS guidance with the Captain. On departure, we had strong crosswinds (gusts > 30 knots) directly off the right wing, however, no LLWS or Micro-burst activity was reported at the field. After verifying LNAV, selecting ge…

What I'm gathering from these reports is not encouraging: (1) The third report says that MCAS only operates in manual flight. The second report appears to confirm that since the pilot says he engaged autopilot sooner than usual to remove the possible MCAS threat. (2) However, both the first and second reports describe uncommanded pitch down events while in autopilot . That means there is another problem in addition t…

Which Airbus model is affected?

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#124

Post by mimixco »

mannykannot wrote: post #105
mimixco wrote: post #82

Earlier quoted context omitted.

In both the first two cases, the pilots knew about potential MCAS issues and discussed them with each other before take-off -- and they still had (terrifying) problems.

In those cases (if they are not two reports of the same incident), while MCAS was discussed prior to the flight, the actual incident appears to be autopilot related, and there is no mention of the trim running away and having to be disabled. In fact, the Captain's report mentions that he chose to engage the autopilot earlier than usual, "to remove the possible MCAS threat."

I'm a developer and not a pilot but I think that's pretty relevant. In both of those (two separate) cases, the pilots were aware of MCAS (it's not supposed to run when autopilot is on, right?) and tried to avoid any interference from it, yet they experienced interference anyway. One of those examples was nose down which sounds like MCAS and the other was unexpected leveling off at the wrong altitude.

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#125

Post by mimixco »

mannykannot wrote: post #61
tuna-piano wrote: post #30

Some context: 1. There have been 865 737 related ASRS reports since 1/1/2018 2. I don't know how to quickly separate out 737-MAX reports from the non 737-MAX reports, as the ASRS database doesn't include 737-MAX as an airplane type! From scanning, I can say that there are more than five MAX related reports, though. [1] All 865 737 reports since 1/1/2018 CSV - http://s000.tinyupload.com/index.php?file_id=5466867979406…

Thanks for the documents! I searched through item 1 for 'trim', and while I found some trim failure reports, and the complaint about Boeing's nondisclosure of MCAS in its documentation, I did not notice any concerns over disabling a runaway trim situation.

Not a pilot here (developer) but doesn't "nose down" imply trim? If so, one of those pilot reports in the Dallas News story does say that they experienced uncommanded nose down. Both pilots were aware of MCAS and discussed it before the flight. Another one who also knew of MCAS reported uncommanded leveling-off at the wrong altitude. Is that not trim, too?

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#127

Post by dtagames »

tuna-piano wrote: post #71
mannykannot wrote: post #61

Earlier quoted context omitted.

Thanks for the documents! I searched through item 1 for 'trim', and while I found some trim failure reports, and the complaint about Boeing's nondisclosure of MCAS in its documentation, I did not notice any concerns over disabling a runaway trim situation.

Not sure what that means though. As far as I am aware (totally a layperson), there have been potentially only 3 potential 737-MAX MCAS trim issue occurrences: 1. The Lion Air flight prior to the fatal lion air flight 2. The Lion air flight which crashed 3. The Ethiopian flight which crashed Of course I don't think any of those 3 are absolutely confirmed, but I do think it seems likely the three had MCAS trim related…

From the database, #1597286, "agressive" uncommanded nose down.

Day 3 of 3 departing in a MAX 8 after a long overnight. I was well rested and had discussed the recent MAX 8 MCAS guidance with the Captain. On departure, we had strong crosswinds (gusts > 30 knots) directly off the right wing, however, no LLWS or Micro-burst activity was reported at the field. After verifying LNAV, selecting gear and flaps up, I set "UP" speed. The aircraft accelerated normally and the Captain engaged the "A" autopilot after reaching set speed. Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1,200 to 1,500 FPM. I called "descending" just prior to the GPWS sounding "don't sink, don't sink." The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful. We discussed the departure at length and I reviewed in my mind our automation setup and flight profile but can't think of any reason the aircraft would pitch nose down so aggressively.

This sounds very similar to the MCAS problems on the other flights, and these pilots were aware of MCAS (this is post Lion Air).

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#128

Post by purplezooey »

jashkenas wrote: post #53
tuna-piano wrote: post #30

Some context: 1. There have been 865 737 related ASRS reports since 1/1/2018 2. I don't know how to quickly separate out 737-MAX reports from the non 737-MAX reports, as the ASRS database doesn't include 737-MAX as an airplane type! From scanning, I can say that there are more than five MAX related reports, though. [1] All 865 737 reports since 1/1/2018 CSV - http://s000.tinyupload.com/index.php?file_id=5466867979406…

Great links! Here are the three 737-related ASRS reports that mention MCAS: ACN: 1597286 "Day 3 of 3 departing in a MAX 8 after a long overnight. I was well rested and had discussed the recent MAX 8 MCAS guidance with the Captain. On departure, we had strong crosswinds (gusts > 30 knots) directly off the right wing, however, no LLWS or Micro-burst activity was reported at the field. After verifying LNAV, selecting ge…

I wish our bugzilla reports were that good

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#129

Post by jussij »

tuna-piano wrote: post #78
mannykannot wrote: post #32

There are at least three inter-related issues here: 1) Was MCAS an issue in the Ethiopian Airlines crash? 2) Did Boeing err, prior to the Lion Air crash, in not informing pilots of the existence of MCAS, and the way it changes how a failure is experienced by the flight crew? 3) Does MCAS pose a risk that cannot be adequately addressed through appropriate awareness and training? IIRC, after the existence of MCAS was d…

> The forthcoming software upgrade for MCAS certainly implies that there were improvements to be made. Not according to Boeing... "Boeing has been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer."[1] To me an incredibly infuriating statement. The 737-MAX has a fatal crash rate of ~4 per million, when compared to .1 per million for the 737-NG model…

It really does not matter what spin Boeing comes up with regarding the cause of these crashes.

The reality is in a very short space of time two 737-MAX have fallen out of the sky.

You only have to look back at the McDonnell Douglas DC-10 to understand once a plane gets a bad reputation, it is doomed.

For an example of how this can go bad so very quickly, here in Australia this issue has become so new worthy, it's now been revealed one our major carriers is planning to introduce the 737-MAX in November.

I suspect just that little fact is going to become a major headache for that particular carrier.

Re: Boeing 737 Max pilots complained to feds for months about suspected safety flaw

#130

Post by siwatanejo »

dajohnson89 wrote: post #121
dpwm wrote: post #45

Earlier quoted context omitted.

regex? I just grepped "B737 max" and found 11 entries. "737.{0,20}max" (case insensitive) yields 20. [0] [0] CSV output: https://pastebin.com/87N023cx

So 20 MAX-related issues out of ~850. How is that significant?

we're talking about a plane model that is only 2 years old?
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