18th of May 2011

A Boeing 707-321B tanker aircraft was scheduled to fly an aerial refuelling mission from Port Hueneme-Point Mugu Naval Air Station, CA, USA. Onboard a crew of three. No abnormalities were noted during the preflight and flight preparation. The take-off was delayed due to strong winds.

The post impact fire (source & © CBS)

Once the wind was within limits the crew headed towards runway 21, the reported wind at the time 280º at 24 knots, gusting 34 knots.

The take-off speeds, V1 (take off decision speed) 141 knots and Vr (rotation speed) 147 knots, were corrected (raised) with 5 knots to compensate for the windgusts and a full power take off was briefed. To avoid engine stalls due to the crosswind component the crew agreed to advance the throttles slowly. At 17.23 local time ATC cleared the aircarf for take off from runway 21 and gave instruction to turn left to a heading of 160º after departure.

The take-off roll was uneventful, and when the co-pilot called "ROTATE", the captain rotated the nose of the aircraft to th initial pitch target of 11º. Shortly after lift off, the aircraft was about 20 feet above the ground, th ecrew heard aloud noise and the left inboard thrustlever (#2 engine) snapped back to the idle position. Full right rudder and nearly full right aileron were used in an attempt to keep the wings level and keep directional control. The aircraft however drifted to the left. The captain sensed the aircraft would not claimed and decided to put the aircraft back on the ground. The nose was lowered and the wings levelled right at the moment the aircraft touched down on the runway. The aircraft bounced several atimesnd drifted left, crossed a taxi and came to a rest in amarsh adjacent to the taxiway. The crew performed the necessary checklists and all three evacuated the aircraft via the escape slide. The aircraft was consumed by a post impact fire.

The #2 engine on the runway, amonst the tire tracks, the aircraft burning in the background.

© Naval Base Ventura County

The crew of a company aircraft saw the events unfold and indicated that the left inboard engine (#2 engine) separated and flew over the left wing. The inlet cowling for the left outboard engine (#1) separated from the engine when it was hit by the #2 engine naccelle. at that point the aircraft started to descend, although the three remaining engines were at maximum power. Pratt & Whitney later indicated that the loss of the inlet cowling would cause such an increase in drag, that the thrust produced by the engine effectively was zero.

The burned out hull (©NTSB)

The NTSB investigated the accident, and on the second of January 2013 published their report, which is available by clicking here. They determined that the probable cause of this accident was the failure of a midspar fitting, which was susceptible to fatigue cracking and should have been replaced with a newer, more fatigue-resistant version of the fitting as required by an airworthiness directive. Also causal was an erroneous maintenance entry made by a previous aircraft owner, which incorrectly reflected that the newer fitting had been installed.