Boeing couldn't give investigators key video of the Alaska blowout 737 Max being repaired because it deletes security footage after 30 days

• The NTSB is looking for security camera footage of work done on the Alaska Airlines blowout plane.
• Boeing told the NTSB that such footage has been overwritten.
• The planemaker previously said it also couldn't find records of work done on the door plug.

Boeing doesn't have security footage of key work done on the Alaska Airlines blowout plane, according to a letter sent by the head of the National Transportation Safety Board on Wednesday.

The NTSB is investigating the January 5 incident that saw a door plug — which covers a deactivated emergency exit — come away from a 737 Max 9 in midair.

NTSB boss Jennifer Homendy wrote to Maria Cantwell and Ted Cruz, the chair and ranking member of the Senate Committee on Commerce, Science, and Transportation.

The letter provided more insight into how Boeing is working with investigators, following Homendy's testimony last Wednesday. During her testimony, she said Boeing didn't give investigators a list of employees or documentation the NTSB requested.

Boeing has said that it is unable to find records documenting work done on the door plug of the Max 9 involved in the blowout.

The door plug had been opened in Boeing's factory in order to repair rivets. In its preliminary report, the NTSB said the jet left Boeing's factory without key bolts that keep the door plug secured.

"To date, we still do not know who performed the work to open, reinstall, and close the door plug on the accident aircraft," Homendy said in the letter.

She added that the NTSB had requested security camera footage in order to figure that out.

Boeing replied that the footage had been overwritten.

Homendy noted that the NTSB didn't want to find the Boeing staff who did the work for "punitive purposes," but rather to interview them for more details about Boeing's safety culture.

A Boeing spokesperson told Business Insider that the planemaker's standard practice is to maintain security footage on a rolling 30-day period. The incident aircraft was in Boeing's factory in September 2023 and delivered to Alaska Airlines a month later.

"We will continue supporting this investigation in the transparent and proactive fashion we have supported all regulatory inquiries into this accident," they added.

"We have worked hard to honor the rules about the release of investigative information in an environment of intense interest from our employees, customers, and other stakeholders, and we will continue our efforts to do so."