737 Max: Loose Rudder-Control Fastener Issue.
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Back to the bolts, if you please.
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421dog - I think you will find that the problem is that plenty of people have died. Given recent events, it is extremely fortunate that a whole lot more did not. I think the MAX has now run out of rope. If some other significant incident/accident occurs that can be reasonably laid at the feet of the manufacturer or the aircraft itself then it will have a catastrophic effect on the willingness of passengers to fly on those aircaft. Whether that is fair or not becomes a moot point. Consumer confidence is very hard to define in absolute terms. However, we all know when it is exists and when it does not.
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Its one of the reasons holding up cert on the MAX 7.
On the MAX door plug bolts...the FAA has rejected Boeings inspection procedures.
Its a door plug, not a plug door...that difference in design is significant.
Trying to find a discussion oN pprune about the flight deck door opening on decompression.
this appears to be a significant design flaw....
While "loose lips sink ships"
loose nuts crash aircraft
Paxing All Over The World
Airline regulators will not be rushed into clearing grounded Boeing 737 Max 9 planes after a mid-air blowout, the US government has said.
The aircraft, which were suspended in the US following an incident on an Alaska Airlines flight "need to be 100% safe", said Transportation Secretary Pete Buttigieg.It is unclear when the planes will be allowed to fly again.
Boeing's boss, Dave Calhoun, described the incident as a "quality escape".
Boeing's boss, Dave Calhoun, described the incident as a "quality escape".
PAXboy, I guess you aren't up on maintenance and production jargon.
Quality Escape is a professional's term that applies to cases like this, and it isn't limited to Boeing-speak.
Here is some reading material for you to take a look at.
The-Analysis-of-Quality-Escapes-in-the-Aerospace-Defense-Industry.pdf (ren-services.com)
And a bit of motherhood
The Qantas A380 flight over Malaysia (much discussed on PPRuNe) whose RR/Trent turbofan lost a turbine disc was, all said and done, a RR Quality Escape. (Investigatore eventually found out the root cause for why the lube line failed which led to the chain of events that resulted in the turbine disc leaving the aircraft...uncontained...)
(In comparison, the MCAS mess was a combined design and systems training system error, or at least that how I'd categorize it).
Quality Escape is a professional's term that applies to cases like this, and it isn't limited to Boeing-speak.
Here is some reading material for you to take a look at.
The-Analysis-of-Quality-Escapes-in-the-Aerospace-Defense-Industry.pdf (ren-services.com)
In gross terms, quality escapes are nothing more than inability to manage the details. Not surprisingly, the root causes of numerous quality escapes are found in the flow and interpretation of technical requirements. These root causes often take the form of ambiguity in the original requirements, failure to adequately evaluate the results of requirements interpretation, or simply overlooking the requirements.
In fact, the current quality imperative across all industry sectors has focused a harsh light on quality escapes.
Six Sigma has become the stated objective of prime contractors and their suppliers across the aerospace supply chain. Industry sponsored organizations which formulate quality policies and procedures have instituted strict standards (e.g., AS9100) which exceed ISO in their requirements.
This is particularly true in areas such as management of characteristics, control of manufacturing processes, adherence to specifications, and configuration management. Aerospace prime contractors are increasingly requiring their suppliers to achieve AS9100 registration.
The industry is also applying the first article inspection methodology prescribed in AS9102 which places strong emphasis on characteristic accountability. This emphasis is largely based on the recognition that many quality escapes happen with the very first production unit as a result of an inadequate first article inspection. {Renaissance Services White Paper: The Analysis of Quality Escapes in Aerospace & Defense 2} With all of this emphasis on quality, the continued occurrence of escapes is a driving factor in the establishment of programs such as e-LINCS. While AS9100 and related standards seek to legislate a certain level of quality behavior, the tools needed to ensure confidence in their compliance are largely absent from the primes and their supply chain.
Six Sigma has become the stated objective of prime contractors and their suppliers across the aerospace supply chain. Industry sponsored organizations which formulate quality policies and procedures have instituted strict standards (e.g., AS9100) which exceed ISO in their requirements.
This is particularly true in areas such as management of characteristics, control of manufacturing processes, adherence to specifications, and configuration management. Aerospace prime contractors are increasingly requiring their suppliers to achieve AS9100 registration.
The industry is also applying the first article inspection methodology prescribed in AS9102 which places strong emphasis on characteristic accountability. This emphasis is largely based on the recognition that many quality escapes happen with the very first production unit as a result of an inadequate first article inspection. {Renaissance Services White Paper: The Analysis of Quality Escapes in Aerospace & Defense 2} With all of this emphasis on quality, the continued occurrence of escapes is a driving factor in the establishment of programs such as e-LINCS. While AS9100 and related standards seek to legislate a certain level of quality behavior, the tools needed to ensure confidence in their compliance are largely absent from the primes and their supply chain.
(In comparison, the MCAS mess was a combined design and systems training system error, or at least that how I'd categorize it).
Last edited by Lonewolf_50; 11th Jan 2024 at 13:36.
I'm always looking for good examples where 'obvious' control measures are not as good as people expect: could you give me a pointer/link to the relevant research providing evidence that "there is 10% chance that duplicate inspection will not catch the fault". A quick Internet search hasn't given me any obvious candidates - and a lot of procedures are designed around (semi-)independent sign-off, as in: A does the job and logs it as done, B checks and logs that it has been checked. It's relevant in many areas, not 'just' aircraft maintenance.
Change of thread topic needed?
No, you are not.
However, I think it would be useful if the thread title were changed to 737 Max: Loose Rudder-Control Fastener Issue.
It is unfortunate that the Alaska airlines door-plug blowout seems to be narrowing down to loose or missing fasteners as well. While it is possible that there is a common Quality Control / Quality Assurance issue at play, it is confusing.
However, I think it would be useful if the thread title were changed to 737 Max: Loose Rudder-Control Fastener Issue.
It is unfortunate that the Alaska airlines door-plug blowout seems to be narrowing down to loose or missing fasteners as well. While it is possible that there is a common Quality Control / Quality Assurance issue at play, it is confusing.
routine presence of foreign object debris [FOD] in Spirit products, missing fasteners, peeling paint, and poor skin quality.
Some would appear to be "human error" in that a human did not insert a bolt, torque the bolt to the correct value and insert a cotter pin.
Some of the terminology coming from the FAA is disheartening.
"bolt with missing nut" Obviously the "missing" nut was found!
"a plug type passenger door". Surely it is "a emergency exit plug "
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As a long retired 80-something engineer in both the aviation and nuclear industries, as both a producer and an inspector, I suspect that there has been too much attention paid to posh-sounding jargon and too little attention to the nitty-gritty detail of turning out good-quality work. Too much focus on money always produces these issues.
As a long retired 80-something engineer in both the aviation and nuclear industries, as both a producer and an inspector, I suspect that there has been too much attention paid to posh-sounding jargon and too little attention to the nitty-gritty detail of turning out good-quality work. Too much focus on money always produces these issues.
(See the back and forth about door plug and plug door as but one example).
As I suggested above, it is useful in this case, I think, to differentiate between a design error (MCAS), a training system error (MCAS) and a process error (these bolts). Why? Because getting the right solution/correction is aided by identifying the problem and the cause.
(And of course, some the jargon is tribal short hand which doesn't help much ... )
https://www.faa.gov/newsroom/faa-inc...-manufacturing
WASHINGTON, D.C. — After taking decisive and immediate action to ground approximately 171 Boeing 737-9 MAX planes, the Federal Aviation Administration (FAA) today announced new and significant actions to immediately increase its oversight of Boeing production and manufacturing. These actions come one day after the FAA formally notified Boeing that the FAA has launched an investigation into the company as a result of last Friday’s incident on a Boeing Model 737-9 MAX in which the aircraft lost a passenger door plug while in flight.
The actions announced today include the FAA conducting:
Yesterday, the FAA announced an investigation to determine if Boeing failed to ensure completed products conformed to its approved design and were in a condition for safe operation in compliance with FAA regulations. The letter to Boeing is available here.
The safety of the flying public, not speed, will determine the timeline for returning the Boeing 737-9 MAX to service.
WASHINGTON, D.C. — After taking decisive and immediate action to ground approximately 171 Boeing 737-9 MAX planes, the Federal Aviation Administration (FAA) today announced new and significant actions to immediately increase its oversight of Boeing production and manufacturing. These actions come one day after the FAA formally notified Boeing that the FAA has launched an investigation into the company as a result of last Friday’s incident on a Boeing Model 737-9 MAX in which the aircraft lost a passenger door plug while in flight.
The actions announced today include the FAA conducting:
- An audit involving the Boeing 737-9 MAX production line and its suppliers to evaluate Boeing’s compliance with its approved quality procedures. The results of the FAA’s audit analysis will determine whether additional audits are necessary.
- Increased monitoring of Boeing 737-9 MAX in-service events.
- Assessment of safety risks around delegated authority and quality oversight, and examination of options to move these functions under independent, third-party entities.
Yesterday, the FAA announced an investigation to determine if Boeing failed to ensure completed products conformed to its approved design and were in a condition for safe operation in compliance with FAA regulations. The letter to Boeing is available here.
The safety of the flying public, not speed, will determine the timeline for returning the Boeing 737-9 MAX to service.
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A quality control lapse at Boeing discovered in December has proved less significant than it at first appeared. Airlines worldwide have inspected the rudders on the more than 1,400 Boeing 737 MAX aircraft in service globally for loose bolts and found no faults.
Rudder bolts inspected on all Boeing 737 MAXs; no more faults found
Rudder bolts inspected on all Boeing 737 MAXs; no more faults found
