The head of the American Transportation Safety Agency (NTSB) said Wednesday that Boeing was not cooperative enough in the investigation into the incident that occurred on January 5 on an Alaska Airlines flight, but the manufacturer denies it .

“Some parties have been very cooperative, like the United States Aviation Agency” (FAA), said Jennifer Homendy, during a hearing before a committee of the United States Senate in Washington.

But “Boeing has not provided the documents and information that we have requested repeatedly over the past two months,” she said. After these criticisms, the manufacturer assured that it had “worked proactively and transparently to fully support the NTSB investigation”, specifying that its teams worked “tirelessly to provide a complete response to the requests” of the investigators.

Ms. Homendy specifically cited the requests, which remained in vain according to her, concerning the manipulations of the cork door which detached from the cabin a few minutes after takeoff as well as the identity of the 25 people of the team working in this position at the Boeing assembly plant in Renton (Northwest Washington State). “We have repeatedly asked” for this information, said Ms. Homendy, stressing that the head of the team working on these cork doors was on sick leave.

“Either they exist and we don’t have them, or they don’t exist, which raises (…) different questions depending on what the right answer is,” she noted. Boeing said it provided “very early on” the names of Boeing employees that might be of interest to investigators and, more recently, “the complete list of people on the 737 door team.” Ms. Homendy told senators that investigators had been informed by Boeing of the procedure for tracing any intervention on these stopper doors. “But we have not been able to verify it,” she added.

“Without that information, it raises concerns about quality assurance, quality management, the safety management system at Boeing,” she said. For its part, Boeing pointed out that “if the removal of the door cap has not been listed, there is no documentation to share” on this subject. By deductions, in particular from emails, photos and SMS, the Agency is starting to “have an idea” of the date of intervention on the incriminated document, around “mid-September”, said Ms. Homendy. .

According to the NTSB preliminary report released Feb. 6, four bolts that were supposed to secure the door were missing. They had been removed to carry out repairs to the cabin of the plane which entered service in November.