rickair7777

MCAS is not supposed to work with the AP on, it is only intended to keep control forces within certified limits for the PILOTS (50lbs. IIRC) under specific conditions.

If the AP is on, it can do it's own trimming.

The issues reported AFTER engaging the AP may well be some sort of glitch (software possibly), but should not be MCAS normal function.

With Lionair, MCAS appeared to operate correctly, it was just given bad data from the AoA. It should not have been operating but it didn't know that. It did what it was supposed to do.

rickair7777

My understanding is that MCAS will stop if manual trim is used. HOWEVER... if MCAS is still being told a stall/high AoA condition exists it will start trimming again in 10 seconds.

That last is potentially very insidious and confusing, especially if you have lots of things going on in the cockpit. You use trim, correct the problem, and note that trim condition is stable. Then you start looking at other alarms, and then MCAS starts again.

Typically a actual high AoA would be resolved within ten seconds. The designers did not really account for bad AoA data.

FlyF35

Can real Max 8 pilots help us here with these question?

1. If AP is on, will MCAS kick in from your experience or your training? From report of 1st crash, AP is on till end of flight.

2. Vertical speed oscillation per satellite tracking data shows similar pattern for both crashes. I would assume “climb” is from pilot override and “descent” is from either AP or MCAS? In both cases, computer trumped human intervention. Is this correct?

Thanks.

FlyF35

I agree.

If you read FAA statement yesterday, they argue they stick with their principal and the decision is data driven. That is why they are the last to ground 737 Max.

On the contrary, the company and FAA knew something for months after 1st crash. They have the best info among all parties in the world. This is common sense.

So can we say all others who grounded 737 Max earlier are not as data driven as FAA?

The inaction from FAA is not something I can understand.

rickair7777

No, not supposed to. And there's not much experience or training available, that's part of the problem

I recall the AP was off for Lionair, at least after they got into trouble.

Suspicion is that the MCAS interfered with human intervention. The intervention was hand-flying, which cannot be "trumped" by automation, but a slow and intermittent runaway trim could be very confusing.

Dgelles

Hi all, I’m a reporter at the New York Times and am hoping to speak with any Max pilots. Feel free to reach out at 01 212 556 1287, 01 510 292 9576 or [email protected]

Thanks

F4E Mx

If the autopilot is engaged with some kind of altitude dialed in and the 'nose-down mechanism' kicks in (whether it is supposed to be engaged or not) and pitches the nose down the autopilot may attempt to climb again only to have the nose-down mechanism pitch the nose down again.

I flew a new twin that had a similar problem. The signal from the attitude indicator that was supposed to be cancelled when the aircraft leveled off and replaced with a signal from the altimeter never was cancelled resulting an a (mild) pitch up and down motion. Had to take the airplane back to Bendix to find the problem.

kevbo

That 200 hr F/O was probably climbing around the cockpit like a child on a playground. That's the connotation media tries to create. Some parts of the industry are actually that poor yet never mentioned.

FlyF35

For the 1st crash, below is pilot/FO (PIC/SIC) info from the preliminary report (https://reports.aviation-safety.net/...RELIMINARY.pdf). Their flight lasted 11 min, about 2x of 2nd crash.

Pilot in Command
Gender : Male
Age : 31 years
Nationality : India
Date of joining company : 25 April 2011
License : ATPL
Date of issue : 28 July 2016
Aircraft type rating : Boeing 737
Instrument rating validity : 31 May 2019
Medical certificate : First Class
Last of medical : 5 October 2018
Validity : 5 April 2019
Medical limitation : Pilot shall wear corrective lenses
Last line check : 19 January 2018
Last proficiency check : 7 October 2018

Flying experience
Total hours : 6,028 hours 45 minutes
Total on type : 5,176 hours
Last 90 days : 148 hours 15 minutes
Last 30 days : 81 hours 55 minutes
Last 7 days : 15 hours 45 minutes
This flight : About 11 minutes

Second in Command
Gender : Male
Age : 41 years
Nationality : Indonesia
Date of joining company : 31 October 2011
License : CPL
Date of issue : 15 May 1997
Aircraft type rating : Boeing 737
Instrument rating validity: 31 August 2019
Medical certificate: First Class
Last of medical : 28 September 2019
Validity : 28 March 2019
Medical limitation : Pilot shall possess glasses that correct for
near vision
Last line check : 4 July 2017
Last proficiency check : 25 August 2018

Flying experience
Total hours : 5,174 hours 30 minutes
Total on type : 4,286 hours
Last 90 days : 187 hours 50 minutes
Last 30 days : 32 hours 55 minutes
Last 7 days : 20 hours 20 minutes
This flight : About 11 minutes

nfnsquared

https://www.cnbc.com/video/2019/03/1...el-elwell.html


Similar track data between the 2 flights drove the FAA's decision to ground the fleet. Took a few days to run enhancement program to decipher ADS-B raw data.