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New 737

Old 11th Mar 2023, 19:31
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New 737

The day after delivery from Boeing, 737 SWA9017 left Sky Harbor then immediately declared an emergency and returned to field. "No electric stabilizer trim, autopilot inop..."
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Old 11th Mar 2023, 20:21
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It happened on Feb 24. Not much of an issue. The autopilot wouldn't engage because the autopilot stab trim was inop.

They declared an emergency because they had to hand fly the airplane.
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Old 11th Mar 2023, 23:48
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MAX8

Howdy... ordinarily yes. This model was grounded for trim system issues involving the Stab trim. Delivered fresh from the factory, perhaps final checks of trim motor action involved accidentally turning off the motors and not turning them back on? I would have thought the factory would have been especially careful of a trim issue in the aircraft's first hour of commercial carriage. ​​​​​​​Couldn't find any buzz anywhere. Got this on YouTube. Thanks for noting the issue here.
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Old 12th Mar 2023, 00:11
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Google bathtub curve.
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Old 12th Mar 2023, 00:55
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Show of hands - likelihood that someone left the trim cutout switches in the "disable" position and no one tried the wheel trim before starting the take-off roll.
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Old 12th Mar 2023, 01:55
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Controls, "free and correct"... my guess? Pre takeoff check list has included the trim motor switches: "On". Maybe even moved them forward. Out of the pedestal...? One hopes there is now a second AoA sensor/resolver... it would be inadvisable to launch without trim?
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Old 12th Mar 2023, 01:56
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Before takeoff checklist? Unless the trim was already at the takeoff setting.
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Old 12th Mar 2023, 05:19
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Ah, other comments indicate a breaker was pulled for other acceptance testing.

"This is apparently exactly what happened. Circuit braker wasn't replaced after an acceptance trial flight. Aircraft was on the ground for a few hours while mechanics ensured that was the only failure in the system, and the aircraft was returned to service later on the same day." by DERP Squad under https://www.youtube.com /watch?v=3FZ5O2SXuFM

(remove the space in the url - it's the comment, not the video that's the focus.)
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Old 12th Mar 2023, 09:57
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Originally Posted by hunbet
They declared an emergency because they had to hand fly the airplane.
Nice new world we are getting into..
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Old 12th Mar 2023, 10:25
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There is a fair share of heightened anxiety related to this plane, it will take some time to get back to treating it like.... a plane. Trim issues will be sensitive. Declaring an emergency is... well, hard to argue against, but the plane would have had normal backup, having the APLT out of service messes up RVSM, RNP etc, but... oh well. breakers in, system OK.. off we go again.
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Old 12th Mar 2023, 12:02
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I suppose it's reasonable to "Declare an Emergency" in the USA as they don't seem to do (and distinguish between) Pan and Mayday. Thus unless you do this if needing to return to base, you are put at the back of the stack.

They declared an emergency because they had to hand fly the airplane.

Last edited by Senior Pilot; 12th Mar 2023 at 12:44. Reason: Remove pointless comment
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Old 12th Mar 2023, 14:05
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Originally Posted by ATC Watcher
Nice new world we are getting into..
We don't know the motors were switched off. I couldn't access the YouTube link. There are other malfunctions to consider. INOP can also mean "uncontrollable". PM first asked for "loiter", no? Also, the word "replaced". Replacing a breaker is disconcerting. "Resetting" is the word I would look for to "quickly return the A/C to service ... " What is a "Simple" issue that would damage a CB? Leaving a CB open before launch is a critical mistake...who did it and how did it not get reset? So the switches were "check, on". If on and no trim, well RTB is what pilots are paid to do when an issue cannot be resolved in flight. Hand flying MCAS might not be the correct call... ​​​​​​​So, "anxiety around this issue", to me, had nothing to do with crew decisions.

Last edited by Concours77; 12th Mar 2023 at 17:46.
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Old 12th Mar 2023, 17:47
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Not arguing about the actual real technical reasons to declare an emergency , and I agree a trim issue on an brand new Max is probably raising adrenalime more than on another type...It is just this sentence which I find remarkable.
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Old 12th Mar 2023, 21:08
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Some would declare a mayday, some would declare a pan and some would return without declaring an emergency. Truth is, it's subjective and none of them are right or wrong. Yes, flying with manual trim is not a dire situation but heat of the moment who knows what was going through their minds and what else they were dealing with. So, ultimately the only one of the three options that shouldn't be criticised by anyone is the mayday.
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Old 12th Mar 2023, 21:18
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Rock/Hard place

That sentence is inappropriate. Unless I misunderstand, it raised the question of pilot competence, that hand flying is somehow scary or thin to justify Mayday....it is the default, without AP. They had no choice but to handfly. Whether to continue to the destination becomes the issue. The other issue is how did they launch, without trim? They wouldn't have if they knew, imo. So, is no autotrim no go? If MCAS is required equipment for takeoff, is it on the checklist? Also, wouldn't TRIMFAULT (sorry) be on ECAM in position?

Last edited by Concours77; 12th Mar 2023 at 21:36.
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Old 12th Mar 2023, 21:24
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Originally Posted by Concours77
That sentence is inappropriate. Unless I misunderstand, it raised the question of pilot competence, that hand flying is somehow scary or thin to justify Mayday....it is the default, without AP. They had no choice but to handily. Whether to continue to the destination becomes the issue. The other issue is how did they launch, without trim? They wouldn't have if they knew, imo. So, is no autotrim no go? If MCAS is required equipment for takeoff, is it on the checklist? Also, wouldn't TRIMFAULT (sorry) be on ECAM in position?
C77, if you're referring to my post then perhaps you should read it again. In no way was it intentionally critical.
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Old 12th Mar 2023, 21:32
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Originally Posted by Confusious
C77, if you're referring to my post then perhaps you should read it again. In no way was it intentionally critical.
No sir, I was replying to ATCwatcher's post regarding hunbet's post about hand flying. Your post popped up after mine and I missed it....my apologies. Conc​​​​​​​
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Old 12th Mar 2023, 21:35
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Originally Posted by Concours77
No sir, I was replying to ATCwatcher's post regarding Pegase post about hand flying. Your post popped up after mine and I missed it....my apologies.

Conc
No problem C77.
Safe and happy flying to you and all here.
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Old 12th Mar 2023, 21:41
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