DBEA55AED16C0C92252A6554BC1553B2 Clicky DBEA55AED16C0C92252A6554BC1553B2 Clicky
April 18, 2024
Boeing HQ
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Much like the FAA’s proposed airworthiness directive for the 737 MAX from last month, the FAA is also likely to mandate action on another engine de-icing system problem with the Boeing 787 Dreamliner. After releasing a scathing report from the FAA administrator, this has not been an excellent week for Boeing.

While the FAA does not consider either problem an imminent risk to flight safety, the flaw could damage aircraft engines in certain circumstances. The proposed airworthiness directive would require airlines to fix the potential problem in 30 months, reflecting the relatively low risk of this flaw. The ducting that delivers hot air to the engine inlet as a part of the de-icing system has seals at connecting points in the inlet. The seals have proven to have durability issues, leading to hot air leaking into the compartment and exposing composite and metal inlet components to high temperatures. Thermal damage and discoloration have been found in “fewer than two dozen” that could lead to reduced structural strength and separation of the inlet from the airplane.

The separation of the inlet could result in the front of the engine pod separating from the airplane, potentially striking a wing, tail, or fuselage. A strike in the wrong place could result in “loss of continued safe flight and landing or injury to occupants,” according to the proposed airworthiness directive.

Certification Issues

The question must be asked is how this flaw with seals and the single point of failure on the 737 MAX backup power supply slipped through the certification process. With the former, the issue of degradation of the seals faster than anticipated is new information, but the latter was a design flaw.

While Boeing has discovered several flaws with its aircraft that require regulatory action, this is good and bad news. The good news is that Boeing has a strong on-going review and analysis of potential safety issues and acts transparently about them to correct problems. The bad news is the high number of flaws and Boeing’s less-than-transparent process during the MAX certification that led to MCAS. Boeing appears to have received and is acting on the message that the FAA is no longer a rubber stamp for Boeing engineers and that the ODA process must be free of management interference.

The manufacturing issues represent an entirely different set of issues than design problems. Quality issues from manufacturing have continued, and the FAA remains in charge of 737 MAX production, having pulled back parts of Boeing’s production certificate authority. The review of Boeing’s production quality was scathing and is the subject of an entirely different set of regulatory processes.

Nonetheless, another proposed AD for the MAX regarding a missing washer and nut reflects poorly on quality control issues, and illustrates the thoroughness and significance that any problem is now taken.

The Bottom Line

The last thing Boeing needs is additional safety concerns in the public domain when confidence in the company’s products is falling. While we have not yet seen folks avoiding the 737 MAX as they did immediately after the two fatal crashes, each additional problem adds to the aircraft’s reputation as less safe than the competition.