An initial report by the National Transportation Safety Board (NTSB) has said that it is likely that up to 4 bolts were missing from the emergency exit door panel that detached in flight from an Alaska Airlines Boeing 737 Max 9 last month causing an explosive decompression.
The 737 Max 9 was forced to make an emergency landing as a result of the incident.
The NTSB revealed that the door panel had been removed during production to fix “rivet damage” and that the bolts had been removed by Boeing employees but appear not to have been replaced.
The findings will mount more pressure on Boeing which has suffered a raft of quality control issues on its 737 Max and 787 production lines.
Checks on other 737 Max 9s by other airlines ordered in the wake of the Alaska airlines incident have found loose bolts on the same emergency exit.
The bolts in question are the main bolts that hold the exit door, which acts as a fuselage plug, in place.
The report said that “The investigation continues to determine what manufacturing documents were used to authorize the opening and closing of the plug during the rivet rework,”