Wiring Issue Emerges On MAX


The detailed probe of the Boeing 737 MAX certification has uncovered a potential wiring problem that might require modifications to all 800 airframes built so far and may also affect thousands of 737NGs. The New York Times is reporting that the examination found a couple of wiring bundles that control the tail may be too close together, creating the risk of a short circuit. Boeing found the problem and reported it to the FAA and the issue is being discussed by top company officials, the Times reported, citing unnamed sources.

According to the Times the fix is relatively simple and involves the installation of a clamp to create more space between the bundles. It will take about one to two hours for each aircraft. “We are working closely with the FAA and other regulators on a robust and thorough certification process to ensure a safe and compliant design,” Gordon Johndroe, a Boeing spokesman, said in a statement to the Times. “We identified these issues as part of that rigorous process, and we are working with the FAA to perform the appropriate analysis. It would be premature to speculate as to whether this analysis will lead to any design changes.”

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.

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  1. In comparison to the ad nauseam blathering and diatribe over MCAS, I don’t see this as a big issue. Adding a clamp and a couple of hours of labor to install it is no biggie in and as of itself. It’s good that Boeing found it and came “clean” ASAP, too.

    A larger issue might be why it happened in the first place and why it hasn’t been found until now? In these days of CAD/CAM, what it shows is that Boeing is in too big a hurry to build airplanes. Why didn’t the QA function find this issue sooner? Maybe the QA function isn’t large enough or doesn’t carry enough clout?

    Just a couple of days ago, I saw a chart where Airbus actually worked overtime last month to crank out 863 airplanes in 2019; Boeing would have produced similar numbers were it not for the grounding of the Max. In 2011, both were producing around 500 airplanes per year. That’s a LOT of serious airplanes and a fairly steep production growth in the nine year period; up to more than two a day had the Max not forced the production curve severely downward. I think it’s time for both Companies to slow down a little bit and start focusing on the fact that the machines they’re building MUST be perfect the first time. This isn’t an aging aircraft problem … it’s a faulty design issue.

    • “In these days of CAD/CAM?” For the benefit of those outside of the engineering community, where you and I served life sentences, yes.

      As the design tools have evolved, they have shed brighter light into deeper corners. Wanna watch engineers’ heads explode? Bring up a high-level assembly on screen, and press the little button that says “find rules violations.” Newer (sometimes merely different) tools find more (or merely different) violations – even when the design has not changed one bit. That MAY be what happened here. The original design of the 737 was done in pencil on vellum. God bless T-squares and slide-rules.

      And then, there are the thousands of everyday “fixes” that are implemented by Manufacturing, that never find their way back to the Design group, for documentation. We all know that is NOT supposed to happen. But we all know that IT DOES.

      A long-time friend and colleague is fond of saying: “at some point, you have to shoot the engineers, and ship the product.”

      Over the weekend, I watched a video on YouTube: “Building the Massachusetts Turnpike.” The construction of 126 miles of I-90, from the New York boundary, to I-95 in greater Boston – in 1956 – took two years. Seriously. No CAD.

      To a perverse extent, we HAVE allowed the Perfect to become the enemy of the Good.

      Why is that so bad? Truth: NOTHING is perfect.

      I can’t remember how to say that in Latin. 😉

      • Nihil simul inventum est et perfectum.

        That’s why I stated that the QA function fell on their swords after SO many airframes have been produced. They’re too focused on quantity at the expense of quality.

        When I went to school, you could tell the engineers from the rest of the social studies types by the slide rules hanging from their belts. That was BEFORE the HP35. And I’m sure you’ve worked for hours doing an ink drawing only to have it go bad, too.

  2. “unreported concerns with the wiring that helps control the tail of the Max.”

    This sounds like the movie called SST Deathflight from the 1970’s.
    In the movie, they brilliantly bypassed the hydraulic flight controls electrically.
    Why can’t 737 crew members just bypass the electrical systems and use hydraulics to fly the plane?

    • “Wiring that helps control the tail of the airplane” would include telemetry from sensors that measure the positions of the control surfaces, and it would include power and control wiring for jackscrew motors. Not good jobs for hydraulics.

      • When I see “potential” and “might require” in the very same sentence from a NYT article, I know immediately to tune out the rest of the story. NYT is becoming notorious as of late for using one data point to define a sphere and 2 data points to define a universe.

  3. So all we need to do is move one wiring bundle a few inches and everything is fine. Hooray! The last deck chair has been re-arranged and the Titanic can continue on course.

  4. I have a feeling that if this had been discovered on any Airbus plane it would not have even prompted a back-page news article. Just because it has the words Boeing and MAX associated with it, the news media has to make a federal case out of it. Too close together? How close is too close? Unless Boeing is using bare copper wire, actual physical contact for some time is needed to create a short. Yes, it is a potential problem, and yes, it needs to be fixed, but it is hardly front-page news. Yars is right; between the design department and the manufacturing floor, things happen.