737 MAX some airframes withdrawn from service.

[macdo]

Credit to Daily Telegraph 13:49 9th April 21
"Boeing is back in the headlines: Southwest Airlines is removing 30 of its 58 Boeing 737 MAX 8 planes from its schedule after a notification from the planemaker over a potential electrical issue, it said on Friday.

The airline said it has not experienced any known operational challenges related to the issue but has removed the 30 MAX 8s for further review.

"Southwest anticipates minimal disruption to our operation," it said (via Reuters).

The 737 MAX was grounded in 2019 after two crashes that killed 346 people. The plane was re-certified for flight by the FAA in November. "

Additional reporting here, may be behind paywall, would appear United and American also doing the same
https://www.thestreet.com/investing/boeing-alerts-customers-on-potential-737-max-production-issue

[stevekstevek]

From NY Times (unfortunately I can’t post link):Boeing said Friday it had notified 16 customers of a potential electrical issue with its troubled 737 Max plane and recommended that they temporarily stop flying some planes.

Boeing said airlines should verify that “that a sufficient ground path exists for a component of the electrical power system” on certain Max planes. The statement comes just months after airlines resumed flying the jet, which had been grounded for nearly two years because of a pair of accidents that killed nearly 350 people.

“We are working closely with the U.S. Federal Aviation Administration on this production issue,” Boeing said in a statement. “We are also informing our customers of specific tail numbers affected and we will provide direction on appropriate corrective actions.”

[PAXboy]

The question is: On which production line were these aircraft made?

[Less Hair]

Not in Charleston.

[DaveReidUK]

Reuters reporting that the 16 affected operators include Alaskan, American, Southwest and United.

[BRE]

Wasn't there an article by an industry insider linked here that maintained the Indenesian crash reeked of an electrical problem?

[EEngr]

PAXboy

Renton. The only 737 production line, AFAIK.

[EEngr]

BRE

I'd heard that this was an autothrottle problem. Which might be electrical. But the sources linked here state that the current problem (sorry about that :O) is related to the electrical power system. That is common to so many aircraft systems that it would be hard to believe it would be missed on the SJ182 flight data recorder.

That Boeing says this problem might affect "certain Max planes" makes me think that it is either related to a particular power system option. Or due to a design change/manufacturing problem affecting a range of the production line sequence.

[pattern_is_full]

Some Boeing 737Maxes grounded because not grounded.

Got it. ;)

[BewareOfTheSharklets]

Taking every shortcut in the book during design, certification and production is really coming back to bite Boeing....

[tdracer]

According to the article in the Seattle Times, the problem was related to a production procedure change that was implemented after the grounding.
So only aircraft delivered since the grounding was lifted are affected.

[FlightDetent]

Sounds like BA is acting professional and responsible. The internet Agora still screams not sufficient and demands perfection or better, Easter living 21st century...

[GlobalNav]

Trust is easier to keep than it is to regain.

[Qbix]

Airbus will never get sober. Yet another bottle of champagne

[krismiler]

Boeing said airlines should verify that “that a sufficient ground path exists for a component of the electrical power system” on certain Max planes.

Sounds like a dodgy earth connection and must be pretty serious to justify grounding, though Boeing are obviously hyper careful with anything MAX related.

It sounds like poor assembly, rather than a problem with the component.

[tdracer]

No knowledge aside what I read in the Seattle Times, but educated guess is that someone came up with a different (easier) way to ground part of the system. The 'continued airworthiness' folks do periodic audits to make sure things age gracefully in-service (this I do know first hand - was involved in some of it years ago) - and they may have discovered that while the grounding path was fine when new (i.e. functional testing), it might not be after it got banged around in service.

Probably worth noting that this was apparently self-reported by Boeing. Maybe they are learning...

[Chris2303]

From Airways Mag Daily

https://airwaysmag.com/airlines/airlines-pull-boeing-737-max-jets/

[Chris2303]

And the Seattle Times version

https://www.seattletimes.com/business/boeing-aerospace/new-electrical-flaw-grounds-more-than-60-737-maxs-adding-to-boeings-woes/

[EEngr]

tdracer

From https://airwaysmag.com/airlines/airlines-pull-boeing-737-max-jets/
"American said in a statement that only the planes it received after the return of the MAX to service were affected."

I assume this means planes they took delivery of after the November '20 re-cert. That's not a lot of service for things to come loose. I don't think they do any sorts of periodic checks on the system connections over such short intervals. So I suspect this was discovered when chasing down some sort of malfunction or anomaly.

[ATC Watcher]

Chris2303

Pretty damning article if true. . . If I read this correctly .someone fixed cable bundles with plastic fasteners instead or the prescribed rivets that were there to ensure grounding , and id this on his own without supervision. Is this usual ?
and then this :
in a previously unreported problem, Boeing recently found a potential defect in a batch of 20 to 40 motors that move the horizontal stabilizer on all 737s, including the MAX and earlier models.
I realize that today Boeing is checking everything twice and is being 100% transparent, and that everything MAX related makes the news today , but it really cannot continue for too long before the flying public vote with their feet...

[Grummaniser]

To be fair, it doesn't say plastic anywhere in the article. Could be something metal but just not as permanent as a rivet

[DaveReidUK]

ATC Watcher

I think you are finding things that aren't in the article.

Firstly, there is no reference to "plastic" fasteners. In fact the term "fasteners" could mean pretty well anything used to attach something to something else.

Secondly, there is no suggestion that the change in process was in any way the decision of the individual carrying out the job. If it was, Boeing have even more problems than we thought.

[ATC Watcher]

oops , re "my definition of "fasteners" it is a translation issue. In our avionic workshop we translate "Kablebinder "as "cable fastener "while in fact the correct translation should be "tie-wrap" . this is what I had in mind, hence my reference to plastic. I did not realize you could have metal fasteners. I learnt something.
On the without supervision , well that is what the article says :, FAA spokesperson Ian Gregor said Boeing’s manufacturing switch from rivets to fasteners was “a minor design change” that did not require approval by either the federal safety agency or the internal Boeing organization that represents the FAA and assures compliance with regulations.
That is the supervision I meant.

[ivor toolbox]

Usually means a swap to nuts, screws ( bolts) and washers as an alternate to rivets. You would not retain a power supply unit to a avionic rack with tie wraps, think someone is losing a lot in translation

[DirtyProp]

Some of them, not all it seems.

https://www.krqe.com/news/latest-news/boeing-warns-of-possible-electrical-issue-in-some-737-max-airplanes-telling-airlines-to-address-prior-to-further-operations/

The Chicago-based airplane manufacturer told 16 customers to look at a possible electrical issue in a group of before “further operations.”

“The recommendation is being made to allow for verification that a sufficient ground path exists for a component of the electrical power system,” Boeing said in a statement Friday morning.

Edit: didn't see the previous thread, apologies.

[esa-aardvark]

Remember, years ago, receiving some USA electronics boxes placarded
'caution heavy ground currents'. Our European supply wiring expected
ground current to be fault current, and trip the supply. Seems Neutral and
Earth were a bit mixed up. Lots of troubleshooting until the lease could be ended.

[Lyneham Lad]

More problems for Boeing (article on Flight Global)

New 737 Max issue affects nearly two dozen airlines, 106 jets: FAA (https://www.flightglobal.com/airframers/new-737-max-issue-affects-nearly-two-dozen-airlines-106-jets-faa/143443.article)

Article intro:-

The US Federal Aviation Administration has disclosed new details about an electric problem that forced the grounding of more than 100 recently-produced Boeing 737 Max.

Though the issue primarily affects jets delivered by Boeing after the FAA lifted the grounding in November 2020, several Max delivered before the grounding are also affected, according to the agency.

The issue involves “potential degradation of bonds associated with electrical grounding of equipment that could affect the operation of certain systems”, says the FAA in a 22 April “Continued Airworthiness Notification to the International Community”.

Potentially affected Max systems include standby power control units, “P6” circuit breaker panels and main instrument panels, it adds.

Click the link for remainder of article.

[WillowRun 6-3]

News item in Wall Street Journal (website at present) reporting that FAA is conducted an audit of the source of the electrical system problems, specifically an audit wider in scope and more in-depth than presumably would be the agency's routine. Excerpts from article:

"As part of its audit, the Federal Aviation Administration is investigating why Boeing missed that a minor production change involving drilled holes wound up the root of potential electrical problems" [referencing unnamed sources].

"The audit is expected to delve into issues beyond those addressed by a typical agency review of such problems. Regulators plan to examine how other minor production changes were handled, these people said. The agency’s senior safety managers want to understand whether oversight changes might prevent future mistakes" [also ref. unnamed sources].

The article goes on to quote an FAA directive issued this week, which reportedly said: "the electrical issue could result in the 'loss of critical functions and/or multiple simultaneous flight deck effects, which may prevent continued safe flight and landing.'" (internal quote in article).

Evidently hoping to provide context, the FAA also said - according to the article - the following: “The multilayered safety oversight system caught this issue, and the FAA, operators and Boeing took action to mitigate the issue prior to an incident or accident.”