The UK CAA is modifying CVR maintenance requirements in the aftermath of the probe of a July 2009 incident involving a British Airways Boeing 747
The incident happened on July 11, 2009, and was detailed in a recent AAIB bulletin
. Soon after pushback at Phoenix Sky Harbor, fumes and smoke were detected in the plane's cabin. The captain decided to return to the gate, but the intensity of the fumes and smoke was enough to warrant an emergency evacuation. The UK AAIB couldn't determine what caused the fumes.
The probe was hampered by a lack of information from the aircraft's CVR. During the probe, investigators discovered that the CVR, designed to preserve the last two hours of conversation, continued to run during post-incident maintenance activities. A probe of other incidents found similar losses of information in 19 of 99 CVR replays reviewed.
AAIB made two recommendations as a result. The agency recommended that British Airways review its flight and maintenance training procedures to ensure that crews are being properly trained and empowered to isolate data recorders in the event of an incident. AAIB also told CAA review its regulations.
CAA, in a response to the AAIB released this past week (.pdf)
, said it plans to have a new chapter on CVR maintenance requirements published by the end of the year.