LONDON A British Airbus-made Voyager military aircraft carrying 198 people plummeted thousands of feet during a flight to Afghanistan last month because a camera became wedged against a control stick, an interim report said.
The report did not say how the camera came to be in the cockpit but said it was confident "human factors" and not technical error was the cause of the incident.
The preliminary conclusion removes blame from the Airbus-led AirTanker consortium, which is under contract to supply Britain with 14 of the converted A330-200 jets in a 14-billion-pound (13 billion pounds) deal.
The Royal Air Force (RAF) said on February 12 it had grounded its fleet of six Voyager aircraft after an "inflight issue" three days earlier which saw the Afghanistan-bound plane being diverted to Turkey. It lifted the suspension on February 21.
In its interim report, the Military Aviation Authority (MAA) said the aircraft pitched nose down while flying at 33,000 feet and fell 4,440 feet within 27 seconds before its self-protection system helped it recover.
The MAA said the flight data and cockpit voice recorders showed movement of the captain's side stick and seat caused the aircraft to pitch downwards. This, it said, was caused by a digital SLR camera that had lodged between the captain's arm rest and the base of the control stick.
"The Flight Data Recorder has shown no indication of system failures which could have led the aircraft to pitch down," the report said.
The roughly 1,000 commercial Airbus A330s in service with airlines were not grounded after the incident.
The AirTanker consortium, which also includes Babcock, Cobham, Rolls-Royce and Thales, said it welcomed the findings.
(Reporting by Brenda Goh; Editing by Janet Lawrence)