EA CO AS wrote:
My workgroup had the opportunity to have a presentation on the MAX by three B737 fleet captains, and they did a very deep dive into the FDR data for both the JT and ET accidents.
These kind of overconfident pilots would have created the next MAX crash.
In an other forum I observed a (first world) MAX pilot contributing a lot about the ET crash. You know what? After being in complete denial the longest time (she said things like: "Boeing did not officially admit, that MCAS exists" or "I am sure, that MCAS played no role, it must have been another technical issue"), she must have come to her senses recently and noticed how embarassing her posts were, as she went and deleted every single post in that thread. Having observed that, I think it is good that the MAX is grounded until these guys get a better understanding of their aircraft.
EA CO AS wrote:
They also had no qualms in pointing out that any B737 type-rated pilot shouldn't have lost either airplane, as both accidents presented as a runaway stabilizer, and the standard checklist for the B737 would have involved engaging the trim cutout switches.
So they simply did not understand how this incidents were presented to the crews.
B.t.w. well know and very experienced US pilots publicly have confirmed this, namely Sully and also Juan Browne.
Pilots seem to have a hard time manually flying the NG when the Automation breaks as well - see ET409.
Thats not correct. Aviation safety globally is phenomenal. The NG being no outlier. Looking at single cases does not change that. In the five years before the MAX appeared one out 4.2 million flights crashed globally (for all possible reasons). The MAX crashed with equally proficient crews about once every 0.125 million flights. From this, it looks that fixing the MAX is the only thing needed to make global aviation safe again.
I gave you the failure rates earlier:
- Crashes per flights 2012-2017 globally: 0.00000024 -> one crash every 4.2 million flights
- As failure rates are additive I can take this as the sum and make an educated guess, how much was primarily a pilot failure and how much was primarily a system failure. Lets say 7/8 were pilot failures and 1/8 were because of system failures. So we get this:
- Crashes per flight primarily due to pilot failures: 0.00000021 (= 0.00000024 * 7/8) -> one crash every 4.7 million flights
- Crashes per flight primarily due to system failures: 0.00000003 (= 0.00000024 * 1/8 = 0.00000024 - 0.00000021) -> one crash every 33 million flights
Therefore, as typically proficient crews would be expected to crash a MAX once every 4.7 million flights, the observed crash rate of 0.000008 (about once every 0.125 million flights) clearly shows the one and only issue: the MAX!
The horrible crash rate of 0.000008 is entirely contributed by the flawed MAX systems. Which makes the MAX contributing a crash causing system failure rate 260 times higher than the 0.00000003 we got for all the other planes.
Therefore, the "just as much"-term in the following statement is hogwash:
and it's not the pilots - it's the training system/airlines penny pinching just as much as Boeing is at fault for penny pinching/in pursuit of profit.
Truth is, fixing the MAX has so much more leverage than doing anything else, that it really should be the only topic. Improving the global crash rate of 0.00000024 is something entirely different and has nothing to do with the MAX grounding.
Can we at least give this argument a rest? Normal automatic trim does not operate continuously for over 9 seconds.
Neither does MCAS if you give a trim input. No, the MCAS incident did not present itself as a trim runaway. Saying otherwise should be put at rest.
They were supposed to run the runaway stabilizer NNC as written which would have them get back in trim before cutting out the switches.
If you would know the NNC, then you would know, that the NNC looks as follows:
* Control airplane pitch attitude manually with control column and main electric trim as needed.
* If runaway stops:
-> checklist completed.
* If not: STAB TRIM CUTOUT switches -> CUTOUT
, page 135
This means, that the MCAS malfunction can not be handled with this NNC because every time the pilot uses electric trim, the runaway stops and the CUTOUT checklist item is never reached.
Last edited by rheinwaldner
on Tue Oct 22, 2019 7:25 pm, edited 1 time in total.