Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

Old 30th Aug 2019, 19:29
  #2101 (permalink)  
 
Join Date: Feb 2017
Location: Isla Grande
Posts: 850
United Airlines pulls Boeing 737 Max from schedules until Dec. 19
gearlever is offline  
Old 30th Aug 2019, 22:23
  #2102 (permalink)  
 
Join Date: May 2011
Location: NEW YORK
Posts: 587
Think the discussion of financials needs to be in a separate thread.
Financial issues for Boeing and the customers get so involved with tax issues and payment contracts that they are futile to discuss from the outside.
etudiant is offline  
Old 31st Aug 2019, 04:31
  #2103 (permalink)  
 
Join Date: Jul 2019
Location: Mass
Posts: 23
Originally Posted by Speed of Sound View Post
Well in the case of the MAX it certainly was down to savings.

Quite simply, Boeing tried to make the 737 more fuel efficient by fitting a 2.5 metre diameter engine to an airframe originally designed for, and fitted with a 1.25 metre diameter engine. MCAS came about to avoid redesign/recertification and huge savings in training costs to their clients allowing Boeing to knock $1 million off the list price of each aircraft. Once the MCAS route was decided upon, further savings were made by including virtually no redundancy, altering trim logic and setting up a massive ‘gotcha’ which claimed 346 lives.

This was very much about making savings, as the technology and skills existed for a better solution but were simply not chosen.
How much would it have cost them to perform some kind of sanity check on the AoA input (assuming single sensor input)? Zero.
How much would it have cost them to design MCAS so that it stopped trimming down at a position short of the max stab trim position? Zero.
How much would it have cost them to design MCAS so that it stopped activating if it was repeatedly interrupted by ANU MET? Zero.
How much would it have cost them to leave the cut-out switch logic the same? Zero. (note: it's far from clear this had anything to do with either accident)

The decision to implement MCAS to solve certification issues was certainly to save costs, but the lousy implementation just looks like a screw up. The bad design decisions (other than perhaps not cross-checking the AoA sensors) didn't save any money.
Notanatp is offline  
Old 31st Aug 2019, 05:29
  #2104 (permalink)  
 
Join Date: Jun 2019
Location: Tana
Posts: 0
Could someone explain this tiny rumour (or maybe it's a known fact, and I wasn't paying attention), please? I read in one of the links posted here, that October 1 marks some important contractual date, after which Boeing has to... do something... start deliveries or re-start deliveries. If they miss this deadline, the airlines will be eligible for cancelling firm orders without paying the penalty. Does anyone know what this is all about and what exactly is this deadline for?

PS Unfortunately, I don't have the link in question and cannot point you to the source.
UltraFan is online now  
Old 31st Aug 2019, 07:26
  #2105 (permalink)  
 
Join Date: Apr 2019
Location: EDSP
Posts: 183
Originally Posted by Notanatp View Post
How much would it have cost them to perform some kind of sanity check on the AoA input (assuming single sensor input)? Zero.
How much would it have cost them to design MCAS so that it stopped trimming down at a position short of the max stab trim position? Zero.
How much would it have cost them to design MCAS so that it stopped activating if it was repeatedly interrupted by ANU MET? Zero.
How much would it have cost them to leave the cut-out switch logic the same? Zero. (note: it's far from clear this had anything to do with either accident)
I agree in so far that compared to the costs piling up now it is close to zero.
However, the actual costs of all the above are not zero. We are talking bronze age embedded systems not iPads. Nothing is easy there. Limited resources - not money wise - may also have been an issue coupled with time pressure.

Last edited by BDAttitude; 31st Aug 2019 at 07:49.
BDAttitude is offline  
Old 31st Aug 2019, 07:44
  #2106 (permalink)  
 
Join Date: Aug 2005
Location: EDLB
Posts: 173
Originally Posted by BDAttitude View Post
I agree in so far that compared to the costs piling up now it is close to zero.
However, the actual costs of all the are not zero. We are talking bronze age embedded systems not iPads. Nothing is easy there. Limited resources - not money wise - may also have been an issue coupled with time pressure.
You need a DAL A system for this. If developed early enough clearly possible with special hardware. However Boeing tried to get away with a cheap solution which is now extremely costly. Wonder how much people at Boeing were in the know of this.
EDLB is offline  
Old 31st Aug 2019, 07:51
  #2107 (permalink)  
 
Join Date: Jan 2008
Location: australia
Posts: 114
Penny Wise Pound Foolish

By way of comparison with costs discussed above, FAA’s Final Rule “Establishment of Organization Designation Authorization Program” - https://www.govinfo.gov/content/pkg/...f/05-20470.pdf - predicted ODA would save over $12m
“There were 10 industry comments that supported the proposed rule as being cost beneficial and one industry comment opposing it. As noted earlier, under certain assumptions described in Section III.C of the Regulatory Evaluation, the present value of the annual reduction in the opportunity costs from the ODA program could be $24.9 million, which is greater than the present value of the compliance costs of $12.3 million.”
Given that the twin certification debacles of B787 lithium batteries and B737 MCAS are attributable at least in part to ODA, FAA’s costing was wrong!
Much else written in the Final Rule is just as questionable.
ozaub is offline  
Old 31st Aug 2019, 07:56
  #2108 (permalink)  
 
Join Date: Apr 2019
Location: EDSP
Posts: 183
Originally Posted by EDLB View Post


You need a DAL A system for this. If developed early enough clearly possible with special hardware. However Boeing tried to get away with a cheap solution which is now extremely costly. Wonder how much people at Boeing were in the know of this.
For new systems for sure. However the question to what extend one can change legacy systems without upgrading them to be fully state of the art (i.e. fulfilling latest standats) is sometimes hazy and aviation industry is not the only industry having skeletons in the closest. But I think you know ;-)
BDAttitude is offline  
Old 31st Aug 2019, 08:36
  #2109 (permalink)  
 
Join Date: Jul 2002
Location: Ireland
Posts: 595
Originally Posted by UltraFan View Post

that October 1 marks some important contractual date, after which Boeing has to... do something... start deliveries or re-start deliveries.
I suspect that the timeline for deliveries is different for each of Boeings individual customers. I doubt that any customers will cancel orders for the time being while Boeing are continuing production of the MAX. Apart from anything else, there are no readily available alternatives, and anything with six wheels and two wings with over 100 seats is already leased to fill the gap.
Speed of Sound is offline  
Old 31st Aug 2019, 08:36
  #2110 (permalink)  
 
Join Date: Aug 2017
Location: London
Posts: 86
Originally Posted by BDAttitude View Post
For new systems for sure. However the question to what extend one can change legacy systems without upgrading them to be fully state of the art (i.e. fulfilling latest standats) is sometimes hazy and aviation industry is not the only industry having skeletons in the closest. But I think you know ;-)
Agreed for hardware. It's usually possible to do a sensible risk assessment and say look, replacing this greased bearing with a ball race is fine because here is a stack of evidence and testing.

But software? No. Changing a single line of legacy code can open a can of worms. Race conditions, overflows, deadlocks... Google that lot. It's like changing the bearing on a door and finding the cabin heater stops working.

It's usually ok to leave legacy code in place on the basis that if it aint broke don't fix it. But a single change (including if you change the hardware it's running on) and really you need to be rebuilding the lot to modern safety critical standards.
PerPurumTonantes is offline  
Old 31st Aug 2019, 18:56
  #2111 (permalink)  
 
Join Date: Apr 2009
Location: A place in the sun
Age: 78
Posts: 787
The FAA is going to be subjected to considerable international scrutiny by a Joint AuthoritiesTechnical Review panel. It will be interesting to see what this reveals:-
https://www.flightglobal.com/news/ar...ficati-460595/
Bergerie1 is offline  
Old 31st Aug 2019, 21:11
  #2112 (permalink)  
 
Join Date: Jul 2002
Location: Ireland
Posts: 595
Originally Posted by Bergerie1 View Post

The FAA is going to be subjected to considerable international scrutiny by a Joint AuthoritiesTechnical Review panel. It will be interesting to see what this reveals:-
https://www.flightglobal.com/news/ar...ficati-460595/
“Boeing says in a statement that ‘work is progressing on software to address the additional requirement identified by the FAA on June 26, which will be submitted for certification with the main MCAS software package that is already complete’".

So a solution is still being sought for the ‘other matter’?
Speed of Sound is offline  
Old 31st Aug 2019, 21:43
  #2113 (permalink)  
 
Join Date: Jul 2019
Location: Mass
Posts: 23
Originally Posted by BDAttitude View Post
I agree in so far that compared to the costs piling up now it is close to zero.
However, the actual costs of all the above are not zero. We are talking bronze age embedded systems not iPads. Nothing is easy there. Limited resources - not money wise - may also have been an issue coupled with time pressure.
I spent 16 years coding and managing software development. About half of my sw career involved a large body of system software written in assembler. I am fully aware of what's involved in the features I discussed in my post, and I wasn't confusing them with programming Java apps on a phone or iPad.

I have no information about what process Boeing actually followed for the design and verification of MCAS, either initially or as it evolved to encompass a second requirement (i.e., low speed maneuvering). I don't know what kinds of specs were written, what kinds of reviews were held and what kind of testing was performed. But whatever process they followed, coding input validation and output constraints would have cost no additional money. Someone would have just had to think of it and do something reasonable. The more formal the process, the more likely this was to happen. But even with no formal process, it is really difficult to understand why the people who implemented MCAS didn't think of any of this.

The truth may eventually prove otherwise, but I have a hard time believing that someone told his manager that they should hold a design meeting to review the requirements and spec for the feature, and the manager said no. There may have been cost and schedule pressures that explicitly or implicitly discouraged a highly-formal development process for MCAS. But it smells more like a situation where the engineers involved simply didn't appreciate the risk presented and thought of it more as a bug fix or minor tweak not requiring formal process, rather than appreciating the risk but intentionally cutting corners on the sw dev process to save money.
Notanatp is offline  
Old 31st Aug 2019, 22:20
  #2114 (permalink)  
 
Join Date: Mar 2019
Location: French Alps
Posts: 306
Originally Posted by Notanatp View Post
But it smells more like a situation where the engineers involved simply didn't appreciate the risk presented and thought of it more as a bug fix or minor tweak not requiring formal process, rather than appreciating the risk but intentionally cutting corners on the sw dev process to save money.
It would take a real rookie to believe that any bug fix or tweak in an FCC program would not require formal process.
That doesn't speak well of the level of competence in the MAX project : there was at least one test pilot and one aerodynamicist involved. And the fix was ordered from the computing company (Collins ?), all without any formal process...Just a phone call or a back-of-the-envelope scribbling...
And they thought they were up to modern aircraft manufacturer standards ?

Fly Aiprt is offline  
Old 31st Aug 2019, 22:40
  #2115 (permalink)  
 
Join Date: Feb 2019
Location: shiny side up
Posts: 431
There may have been cost and schedule pressures that explicitly or implicitly discouraged a highly-formal development process for MCAS. But it smells more like a situation where the engineers involved simply didn't appreciate the risk presented and thought of it more as a bug fix or minor tweak not requiring formal process, rather than appreciating the risk but intentionally cutting corners on the sw dev process to save money.
Not sure I agree, especially when it comes to cert of aviation software.

There is a threshold to where a new version is easily certified for use, (ie expedited review) but that is usually reserved for corrections or modifications to existing code. MCAS was an additional feature, so that would have caused a major level upgrade and the extended certification process.
Boeing was under the gun to get the MAX certified with no new process or requirements, and the expedited review.(ie the $1 million per ac hit with SW)
So I feel that is why they did not tell the FAA, nor the Airlines about MCAS, (it was just veiled under STS)..

That disclosure would have initiated a new version, with full testing, extended review, and of course, the potential for additional training requirements, which we now know was not done.

Face it, there needs to be a V 1.0 of the FMS software, and leave out all of the legacy bugs. A $miilion per ac to SW would have been worth it against the $15 Billion it will cost them.
Smythe is offline  
Old 1st Sep 2019, 01:52
  #2116 (permalink)  
Psychophysiological entity
 
Join Date: Jun 2001
Location: Tweet Rob_Benham Famous author. Well, slightly famous.
Age: 80
Posts: 4,754
I read in one of the links posted here, that October 1 marks some important contractual date, after which Boeing has to... do something... start deliveries or re-start deliveries. If they miss this deadline, the airlines will be eligible for cancelling firm orders without paying the penalty.
I can't help feeling that there will be more than a few get-out clauses, or excuses. I would imagine refusing to take delivery under the present circumstances would end in years of legal argument with Boeing having to bring the cases. I'm perhaps cynical in thinking China may just be weighing up the arguments.

MOL. Love him or hate him, he's a canny bloke and his recent announcement of cut backs will be based on what I fear will be a valid assessment of an aviation decline. His ability to down-size will be a major part of any planning. But then, when you're operating so many of one type, you can't afford to alienate the manufacturer . . . can you?

Many buyers must be considering the ultimate scenario. Fleet numbers and the availability of spares for what is, to all intents and purposes, a new type must be making the thought of a mixed fleet a survivor's equation.
Loose rivets is offline  
Old 1st Sep 2019, 02:52
  #2117 (permalink)  
 
Join Date: Aug 2006
Location: UK
Posts: 127
JATR panel

From the article found by Bergerie1:
"The JATR’s focus on the certification of the aircraft is separate from the ongoing efforts to safely return the aircraft to flight," the FAA says.

The panel's recommendations could affect both the future of how the FAA conducts safety certification and could influence how soon regulators from other nations return the aircraft to service. The FAA's certification of the Max does not require the panel to first finish its review, and Boeing still aims for the agency to clear the aircraft to fly in the fourth quarter.
I'm not sure the JATR's input can be separated from the ongoing efforts to return the MAX to flight. If the panel uncovers issues which bear directly on the plane's safety, they would need to be addressed before the return to service.

Why else might the panel's recommendations influence how soon regulators from other nations return the aircraft to service?
John Marsh is offline  
Old 1st Sep 2019, 03:02
  #2118 (permalink)  
 
Join Date: Jul 2010
Location: Asia
Posts: 589
The COMAC C919 has a considerable amount of American content in it and I'm sure US suppliers would be just as happy to take their money as Boeing's.

Firm orders and bank guarantees are what these companies need to stay in business.

With the recent tariff increase on Chinese imports to the US, getting the MAX flying in China again may be a problem, however these tariffs could be reduced, and Huawei allowed access to Google apps. in return for a CAAC approval of the upcoming Boeing fix.
krismiler is online now  
Old 1st Sep 2019, 04:20
  #2119 (permalink)  
 
Join Date: Jul 2014
Location: Harbour Master Place
Posts: 618
Does the NG have a form of early incarnation of MCAS too? I can't provide certified FCOM documentation to CYA, but I can confirm below is a verbatim copy, found on the web: B737 NG Flight controls, slide 37

It is not really clear to me exactly what is involved in making the stick feel heavy at high AOA from the description, the EFS, STS trim or a combination of both.
Here is the description in question:

"As airspeed decreases towards stall speed, the speed trim system trims the
stabilizer nose down and enables trim above stickshaker AOA. With this trim
schedule the pilot must pull more aft column to stall the airplane. With the column
aft, the amount of column force increase as the EFS module increases pressure to the
elevator feel and centering unit."
CurtainTwitcher is online now  
Old 1st Sep 2019, 14:18
  #2120 (permalink)  
 
Join Date: Feb 2019
Location: shiny side up
Posts: 431
"there are no flight deck indications that the system is properly armed or activated"

Does sound like MCAS...
Smythe is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.