MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
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- Speed Trim failure is not new and has an associated annunciator on the overhead panel. Loss of Speed Trim is not a serious issue.
- Stab Out of Trim is an annunciated malfunction that occurs when there is excess elevator displacement with the autopilot engaged. Also not new. This occurs when the A/P is unable (or slow) to trim the stabilizer. However, the current NNC procedures for Stab Out of Trim would actually delay the appropriate response if this occurs as a result of a Stab Trim Runaway with A/P engaged.
- MCAS is a sub-function of Speed Trim, so presumably a MCAS inop malfunction will be indicated by the existing "Speed Trim" annunciator. Loss of MCAS would also not be a serious issue as long as the pilots maintained vigilance in regard to avoiding high-AOA situations.
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and here is the evidence of that ........ https://www.mro-network.com/maintena...s-mro-invoices Airbus would not be able get away with this if Boeing did not have the issues that they have.
That puts them in the position nearly identical to an old U.S railroad executive - Colis P Huntington- about 140 years ago.
His motto was 'Charge all the ($) the traffic will bear plus a penny"
So airbus comes up with " Charge all the ($) the market will bear plus 1 % "
and here is the evidence of that ........ https://www.mro-network.com/maintena...s-mro-invoices Airbus would not be able get away with this if Boeing did not have the issues that they have.
Although IMHO Airbus have been taking the p*ss out of their customers for several years now.
I know they recently increased the price of their engineering support by several thousand, there is also more and more specialist tooling in the manuals that now have to purchased from Airbus, no alternatives are authorised. One example of this is one tool that if locally manufactured from an approved supplier would cost around 1500 - 2000 USD, Airbus charge 18,000 USD.
The bean counting pin heads and their MBA enablers are getting a long overdue and well deserved lesson in the importance of professional engineering, skilled end user (flight crews) critical input and quality control. The constant push of enhancing every possible smidgeon of “share holder value” might very well cripple the very same shareholders they supposedly held so near and dear. At the end of the day (or months/years) this dumpster fire will be extinguished with a dollar value of damages virtually impossible to fathom.
All they can see is $$$$ signs and for some of them the 346 lives lost is probably just collateral damage.
The remarkable thing to me is that A320 sales have not soared this year. In fact if BA buy their 200 737max Boeing look like winning the year;s sales battle handsomely. I guess a lot of customers are hoping for rock-bottom prices from Boeing and with Airbus unable to deliver for years, there's no incentive to buy from them.
Ah, but the answer is safest practical, not possible.
Deciding what's practical is the hard part in light of diminishing returns.
The first million dollars reduces risk a lot. The next million much less reduction. The next million even less reduction.
How do you decide when it's not worth spending another million?
If an engineer said they could spend 5 million and delay the aircraft another year to mitigate a risk that was thought would never occur, would you as a manager say do it?
How about spending $100k to hurricane proof a house. On the gulf coast sure. 100 miles north, maybe.
But 300 miles north? Could be hit, but that's such a slim likelihood than no sane person would do it.
Deciding what's practical is the hard part in light of diminishing returns.
The first million dollars reduces risk a lot. The next million much less reduction. The next million even less reduction.
How do you decide when it's not worth spending another million?
If an engineer said they could spend 5 million and delay the aircraft another year to mitigate a risk that was thought would never occur, would you as a manager say do it?
How about spending $100k to hurricane proof a house. On the gulf coast sure. 100 miles north, maybe.
But 300 miles north? Could be hit, but that's such a slim likelihood than no sane person would do it.
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As the financial crisis of the MAX drags on, compounded by potentially more costs and disruption with the NG pickle forks and delay with the 777X, if I was the CFO of an airline I would be concerned as to how secure my deposits for all Boeing model jets ordered was. I would be looking at how to protect my money in case Boeing do a repeat of GM where it was able to wipe out all its debts but keep on trading.
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Nope " lives lost" is/was a .000000x decimal point on the power point reference to failure probility versus $$$ to prevent- simply not worth it per MBA analysis.
Just business ..nothing personal . .
Then changes with the FCC, based on the injected faults (when everyone went crazy over the use of a i286) that the FAA wanted, is taking a lot longer.
And from the WSJ article, looks like EASA is the one not liking the current iteration.
The remarkable thing to me is that A320 sales have not soared this year. In fact if BA buy their 200 737max Boeing look like winning the year;s sales battle handsomely. I guess a lot of customers are hoping for rock-bottom prices from Boeing and with Airbus unable to deliver for years, there's no incentive to buy from them.
Even as is, this example of Western profit maximization at the expense of safety will not be forgotten. Few in Asia have reason to love the West and this incident will remind everyone there of the reason why.
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Reuters JATR summaty
Reuters has the summary of the JATR report on both FAA and Boeing. It’s neither better nor worse than expected. Add pilot training issues and maybe maintenance errors and you get a few hundred so fortunately mostly not american dead.
If the corpses had been American in majority the response would have been more effective, the Boeing CEO would have been dumped, and very probably the airframe and training would get properly updated.
https://www.google.fr/amp/s/mobile.r.../idUSKBN1WQ0H8
Edmund
If the corpses had been American in majority the response would have been more effective, the Boeing CEO would have been dumped, and very probably the airframe and training would get properly updated.
https://www.google.fr/amp/s/mobile.r.../idUSKBN1WQ0H8
Edmund
Seattle Times has a similar summary of the JATR findings:
https://www.seattletimes.com/nation-...oeing-737-max/
Is the JATR report public domain? Does anyone have a link to it?
https://www.seattletimes.com/nation-...oeing-737-max/
Is the JATR report public domain? Does anyone have a link to it?
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From the Reuters story on the JATR report:
It seems the panel may have some of the same questions and concerns as some posters here, who have sometimes been answered rather harshly.
The JATR report recommended the FAA review the stalling characteristics of the 737 MAX without MCAS and associated systems to determine if unsafe characteristics exist and if so, if a broader review of the system design was needed.
JATR said MCAS and those systems could be considered a stall identification or stall protection system, depending on how the aircraft handled without them.
JATR said MCAS and those systems could be considered a stall identification or stall protection system, depending on how the aircraft handled without them.
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Seattle Times has a similar summary of the JATR findings:
https://www.seattletimes.com/nation-...oeing-737-max/
Is the JATR report public domain? Does anyone have a link to it?
https://www.seattletimes.com/nation-...oeing-737-max/
Is the JATR report public domain? Does anyone have a link to it?
Tom, #3002.
Thanks for the explanations; these are today’s aircraft - ‘as is’. The interesting issues are ‘what could be’ based on the latest reports, after modification.
The number of ‘Disagree’ alerts and attention-getting stick shake, all result from one failure (AoA), is a concern for the NTSB - pilot workload. Additionally, the consequential ‘Feel Diff ’ alert, AP disengage, and inaccurate EFIS low speed awareness, add distraction.
MCAS modifications could introduce further confusion. If MCAS remains part of the existing Speed Trim (I am not convinced that it is), then the necessary Speed Trim alert would also be given - exacerbating NTSB concerns, and also difficulty in selling the change to other regulators.
There is also need to consider AoA failures where MCAS would be unavailable immediately, not just after takeoff.
After takeoff, even with many distractions, pilots should conclude that stall avoidance and unreliable airspeed actions are required, neither require immediate awareness of MCAS state - it would be distracting.
However, with an AoA failure flaps up, then awareness of MCAS state is important. If MCAS failure / inhibit has to be deduced from many coincident alerts, more than currently deemed acceptable in other 737 variants, would again conflict with the NTSBs views.
There is little if any information on the extent of the flight envelope affected without MCAS operative - no ‘church arch’ diagram of speed / altitude.
‘Stab out of trim’ is currently only with AP engaged; so why raise the point now. If AoA for MCAS is to use both FCCs (most likely) then might this imply that there is a change in AP - MCAS relationship, AP remains engaged, but MCAS unavailable would again have to be deduced, strengthening the need for a new MCAS Unavailable alert.
Without technological detection and alerting for Stab Trim Runaway (not MCAS related after modification), these tasks still depend entirely on human perception. Thence irrespective of how much training is given, correct and timely perception cannot be assured, but in engineering terms assurance is essential for a range of situations including extremes of an uncontrollable aircraft and /or unrecoverable situations due to maximum trim offset.
Thanks for the explanations; these are today’s aircraft - ‘as is’. The interesting issues are ‘what could be’ based on the latest reports, after modification.
The number of ‘Disagree’ alerts and attention-getting stick shake, all result from one failure (AoA), is a concern for the NTSB - pilot workload. Additionally, the consequential ‘Feel Diff ’ alert, AP disengage, and inaccurate EFIS low speed awareness, add distraction.
MCAS modifications could introduce further confusion. If MCAS remains part of the existing Speed Trim (I am not convinced that it is), then the necessary Speed Trim alert would also be given - exacerbating NTSB concerns, and also difficulty in selling the change to other regulators.
There is also need to consider AoA failures where MCAS would be unavailable immediately, not just after takeoff.
After takeoff, even with many distractions, pilots should conclude that stall avoidance and unreliable airspeed actions are required, neither require immediate awareness of MCAS state - it would be distracting.
However, with an AoA failure flaps up, then awareness of MCAS state is important. If MCAS failure / inhibit has to be deduced from many coincident alerts, more than currently deemed acceptable in other 737 variants, would again conflict with the NTSBs views.
There is little if any information on the extent of the flight envelope affected without MCAS operative - no ‘church arch’ diagram of speed / altitude.
‘Stab out of trim’ is currently only with AP engaged; so why raise the point now. If AoA for MCAS is to use both FCCs (most likely) then might this imply that there is a change in AP - MCAS relationship, AP remains engaged, but MCAS unavailable would again have to be deduced, strengthening the need for a new MCAS Unavailable alert.
Without technological detection and alerting for Stab Trim Runaway (not MCAS related after modification), these tasks still depend entirely on human perception. Thence irrespective of how much training is given, correct and timely perception cannot be assured, but in engineering terms assurance is essential for a range of situations including extremes of an uncontrollable aircraft and /or unrecoverable situations due to maximum trim offset.
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Because the current procedure actually delays the crew response to an actual runaway stab trim. I believe this may have been one of the issues in the E-CAB test failure in which the FAA determined that the procedure took too long to implement.
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