Loose Door Plug Bolts Found On United MAX 9s


United Airlines has found loose bolts on emergency exit door plugs on some of its Boeing 737 MAX 9 aircraft. The loose bolts were found as it inspects its fleet of 79 MAX 9s. The Air Current first reported the story, quoting unnamed sources as saying loose bolts were found on five aircraft. United has since confirmed the report but did not say how many aircraft were involved. Aviation journalist Edward Russell posted an image on X that shows the loose bolts, saying it was sent to him by an unnamed source.

“Since we began preliminary inspections on Saturday, we have found instances that appear to relate to installation issues in the door plug — for example, bolts that needed additional tightening,” United said in a statement. “These findings will be remedied by our Tech Ops team to safely return the aircraft to service.” Boeing did not immediately comment, nor did the FAA. Alaska Airlines has not so far reported finding any issues with the door plugs.

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.


  1. “These findings will be remedied by our Tech Ops team to safely return the aircraft to service.”

    Until the next thing surfaces.

    “…bolts that needed additional tightening,” I’d describe that pic, if that’s applicable to this, just a bit differently (less optimistically).

  2. Re the obvious loose bolt. Hey you guys don’t be so hard on Boeing. Their airplanes have lots and lots of bolts and as long as 99.71% are properly torqued they meet the ISO 9000 standard right ?

    In any case it’s not like it’s on some really important piece of the airplane, you know like it being loose could result in a big hole in the side of the airplane……..

    Hat, Coat, Umbrella, Briefcase, Roller bag, check ! I am ready to go to the emergency slide !

  3. It’s tough not to be critical about Boeing these days – perhaps a series of isolated incidents or perhaps just a breakdown of a once-great company

  4. I cant help but think this will drive even more people to use GA instead of the airlines.This is pretty scary stuff, right back to the days with the Comet?

    • What makes you think GA aircraft have any less problems? I have seen issues like this both in the GA world and the airline world. We had 4 loose bolts on our King air 350i after maintenance by Textron on our engine cowling. That too could have been disastrous. Many years ago early in my career I picked up a brand new Cessna 152 from the factory flew it to the Cessna dealership where I flight instructed. One week later the engine failed in the pattern with a student pilot. The bean counters have definitely screwed up Boeing for sure. After 47 years as an airline pilot and GA pilot I have seen a lot of good and bad on both sides. When people cut corners whether in the manufacturing of aircraft or flying aircraft bad things can and do happen.

    • Not unless they are already pilots and have their own airplanes.

      You think ORD-ATL in a middle seat between an overweight guy drinking away his fear, and an unhappy child-in-lap, is bad, try sitting in a C-182 seat for the same trip. With any luck, you and your wife will get door-to-door in about the same time and for about the same money. For a non-nominal flight (wx, equipment, longer distance) all bets are off. Whatever you save in airport parking will be eaten up by ramp fees. If you live on an airport and are visiting friends who do also, you might be able to make the economics work out.

      Yes, this “maintenence issue” is concerning, but no more so than the predictable risk of a pileup on the expressway getting to the big airport. The odds are staggeringly in your favor flying commercial over GA. It’s the flexibility and (relative) comfort that makes GA attractive to those of us with the choice.

      • Unless your wallet is topped off, you shouldn’t be flying xcountry in 182 types. Renting or owning ..

    • I haven’t flown commercial for personal travel since completing my RV-7A build in 2017. Not because of potential manufacturing issues with the big tubes, I just prefer my own schedule and airplane. I just happen to also perform my own maintenance too.

  5. Boeing is going to improve its QA and hopefully its airliners. Let’s not forget these are human endeavors and there will be mistakes, the key is minimizing the consequences. Also the safety of airline travel now is truly remarkable, safer than driving, walking, riding a bike, literally safer than almost anything other than sitting on your sofa.

    A much bigger concern is our ATC system that seems to unspooling before our eyes. If you’re going to lose sleep over something it should be that, better yet let’s get a competent head of DOT instead of mayor Pete to fix it.

    • FAA, debacles and troubles have nothing to do with Buttigieg or the DOT.
      Their troubles , for decades, lay in an entrenched ” Mightier than Thou ” internal attitude which is totally resistant to change and fueld by misappropriated budgets and poor oversight through Congressional inaction and the political ineptness.

    • Agree on the head of DOT. Completely unqualified, which has been proven every time he speaks about airline delays.

      • Intersectionality trumps qualification. The only way to increase Pete’s intersectionality score would be to have him show up in a wheelchair

  6. The finance guys taking over, definitely a mistake.

    Moving the HQ away from Seattle and separating the top guys from both design and manufacturing didn’t help. In the olden days top management would wander out on the shop floor, so to speak, where they were accessible to the working engineers, and the engineers to them. Not any more.

  7. Helicopters have the Jesus nut, right on top of the main rotor. Lose the nut and meet the Lord. Now Boeing has the MCAS Bolt. United Airlines is incredible too; once they knew this plane had a repeating pressurization problem, they limited it’s flights to be over land. Much easier to find a sucked out flight attendant when they’re not a floater I guess. So thoughtful.

    • Rick F.—
      No, you reversed the correct information.
      Alaska Airlines deferred the Mx on the ” cabin pressurization ” cockpit warnings, 3x in the recent month on N704AL after failing to find the source of those alerts, and thus issuing a ” no over water [ie flights to Hawaii] ” order to its flight department.

    • Stop, you’re both right. (paraphrasing the Doublemint commercial no one but me remembers). I meant Alaska AL. My bad.

  8. Look on the bright side. If they can’t use the things for passengers, at least they know now how to turn it into a skydiving plane….

    • Well. Alaska Airlines is said to be soon ” integrating with Hawaiian Airlines ” so we have to see what Hawaiian Airlines has in store for fleet desires and 737 Max 9’s …

    • You made milk come out my nose. Rofl. But it’d take too long to get everyone out just the one door. Better loosen the bolts on the rest of them too.

  9. According to ABC News aviation reporter John Nance, [ ex 737 – 200 / 300 etc.Captain for Southwest Airlines, the cockpit door on Alaska Airlines Max 9 blew open in the depressurization incident, ” sucking pilot’s loose paperwork ” through the door plug hole at Seat row 26 …”

    All those post 9/11 door locks and deadbolts and fortifications were no match for that rapid depressurization cycle.

    • Not the 73, but the Bus AOM says “Two redundant differential pressure sensors enable rapid pressure variation in the cockpit (ha ha it says “cockpit”, we have a female captain that refers to it as the “Box Office” when paired with the same) to be detected, in order to command simultaneous opening of all latches when a defined pressure drop is detected”.

      Not sure if that’s just the door escape panel pins, or the whole shebang, but the AOM differentiates the word latches for the whole kit and kaboodle and pins for the escape hatch. Better than the old “V1, Rotate, Slam!”, Bi fold closet door open, aisle passengers banging into each others heads to lean over because now they have of view out the front prior to 9/11.

      Back to the schoolhouse for remedial training Captain Nance!

    • Cockpit door is designed to blow open on explosive decompression to avoid more serious structural damage.

    • Or an engineering error. Improper bolt material, improper torque on the nuts and or not the specified bolt and nut delivered by the vendor. Many issues to be investigated here, by professionals, not arm chair experts!

    • I’ve read that Boeing delivered the airplane in October 2023, in which case this would seem to be an assembly error.

  10. After securing the flight deck after returning to the gate, the flight crew didn’t pull the CB on the CVR. Seems like that may cause them some grief with the FAA.

  11. I keep coming back to the contractor/sub-contractor bit. Admittedly, I am biased having been through a slew of major projects where whoever was in charge brought in a contractor, didn’t properly supervise/instruct/monitor that contractor, and a mess ensued.

    With Boeing, it seems that an awful lot of this stuff revolves around work by Spirit.

    It would appear to me that the responsible move would be to bring this work back in-house – and – properly monitor it. Given the seeming overbroad influence of the Bean Counters on the processes though, that may be the more difficult lift.

    In my opinion, (which is free, and you get what you pay for – sometimes less – this might be one of those times) Boeing is no longer trustworthy. It’s a damn shame what’s been done to that company.

  12. The entire reason I trust my 1963 Ford is I know damn well theirs no hidden MCAS that’s going to take over.

  13. I think someone on the Boeing assembly line had a bad week, OR he/she was inadequately trained, and Quality Control pencil-whipped the inspection certificate. Why did they need a “plug” anyway, just skin it over and be done with it. Probably would of been cheaper, too.

  14. It appear as though they could put a castle nut and cotter pin on the backside of those 4 bolts and call it good. Or, drilled heads with locktight wire. Otherwise it may become a repetitive inspection after xxx number of hours in service since last inspected.