This information came to light in a letter from NTSB Chairman Jennifer Homendy to the Senate Commerce Committee.

The letter, dated Wednesday, reveals that Boeing, the aircraft manufacturer, has overwritten surveillance footage from the repair facility where the door plug was reinstalled before the flight earlier this year.

‘To date, we still do not know who performed the work to open, reinstall’

The NTSB had previously requested access to this footage to investigate the circumstances of the midflight incident further. However, the agency has been unable to ascertain which Boeing employees were involved in the work on the door plug, which failed and blew out during a flight in January.

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Chairman Homendy stated in her letter, “To date, we still do not know who performed the work to open, reinstall, and close the door plug on the accident aircraft,” and added, “Boeing has informed us that they are unable to find the records documenting this work.”

In response to the ongoing investigation, Boeing issued a statement on Wednesday affirming its commitment to supporting the NTSB’s efforts. “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,” the statement read.

Chairman Homendy also addressed the issue during her testimony before the Senate Commerce Committee earlier this month. She informed the committee members that Boeing had not provided the necessary documents for the investigation, including the names of 25 individuals who worked on the door plug. “The absence of those records will complicate the NTSB’s investigation moving forward,” she expressed.

The NTSB’s initial request for these documents on January 9th was met with the information that the door crew manager was on medical leave. Subsequent requests for updates on February 15th and 22nd were met with a response from the manager’s attorney, stating that the manager was unable to provide a statement or interview due to medical issues.

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Chairman Homendy pressures Boeing CEO for clarity

Following the March 6th hearing, Boeing submitted a list of personnel who reported to the door crew manager to the NTSB. However, this list did not specify who actually performed the work on the door plug. Chairman Homendy then reached out to Boeing CEO Dave Calhoun, requesting the names of the individuals who carried out the work. Calhoun responded that he was unable to provide such information and maintained that Boeing has no records of the work being performed.

Chairman Homendy clarified that the NTSB is not seeking the names of the employees for punitive reasons but rather to protect the identities of the door crew and other front-line employees who come forward.

In a statement to ABC News, Boeing reiterated its comprehensive response to all NTSB requests, providing relevant information. The company had initially provided the NTSB with names of Boeing employees, including door specialists, believed to have pertinent information. Following a recent request, Boeing supplied the full list of individuals on the 737 door team.

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“Early in the investigation, we provided the NTSB with names of Boeing employees, including door specialists, who we believed would have relevant information. We have now provided the full list of individuals on the 737 door team, in response to a recent request. With respect to documentation, if the door plug removal was undocumented there would be no documentation to share.”

“We will continue to cooperate fully and transparently with the NTSB’s investigation,” the company wrote in the statement.