Yahoo TV

STORY: Security camera footage that may show who worked on the door plug which blew off an Alaska Airlines Boeing 737 MAX in January have been overwritten.

That’s according to a letter Wednesday from National Transportation Safety Board Chair Jennifer Homendy to US senators.

The question of who exactly worked on that component of the plane when it was repaired last year has kept federal officials puzzled amid growing scrutiny of work practices at one of the world’s biggest plane makers.

Homendy said “the absence of those records will complicate the NTSB’s investigation moving forward”.

Last week in a Senate committee hearing, Homendy had said she spoke to Boeing CEO David Calhoun and asked for the names of those who performed repairs on the door.

Calhoun said he was unable to provide that information.

She said he told her Boeing has “no records of the work being performed."

A Boeing official told Reuters on condition of anonymity the standard practice at Boeing is to overwrite security videos after 30 days but declined to answer additional questions.

The NTSB said last month four key bolts were missing from the door plug that blew out on the plane.

It turns out the documents detailing the door plug removal, that were required by Boeing’s practices, were never created according to a Boeing letter to a senator on Friday.

At last week’s hearing Homendy also criticized Boeing’s lack of cooperation with investigators and failure to disclose some documents.

She called it ‘absurd’ that the NTSB did not have a 25-name list of door crew at Boeing’s 737 factory, ‘two months later’.

However, hours after Homendy made those comments, Boeing provided the list, according to an NTSB spokesperson.

The Federal Aviation Administration has grounded the MAX 9 for several weeks after an audit found production issues with the jet.

The Justice Department also opened a criminal investigation into the midair emergency in January.