Friday, June 24, 2011

Osprey pilots were blameless victims, widow says

Article at by Marth Quillin and Bob Cox on 19 June 2011

On 8 April 2000 a newly developed V-22 Osprey crashed during a 'mock exercise,' killing those on board. This is an aircraft with tilting rotors, which can land and take off like a helicopter but fly more like a fixed wing aircraft. Following the crash the Marine Corps investigation concluded that "This mishap appears not to be the result of any design, material or maintenance factor specific to tilt-rotors. Its primary cause, that of a MV-22 entering a Vortex Ring State (Power Settling) and/or blade stall condition, is not peculiar to tilt rotors. The contributing factors to the mishap, a steep approach with a high rate of descent and slow airspeed, poor aircrew coordination and diminished situational awareness, are also not particular to tilt rotors." And in announcing the findings of the report, the Marine Corps said in a press release that it "confirms that a combination of 'human factors' caused the April 8 crash of an MV-22 Osprey tilt-rotor aircraft that killed 19 Marines near Marana, Ariz."

However, the families of those who died feel the language used by the Marine Corps was intended to put most of the blame for the accident on the pilots. They feel that the tragic accident "was the direct result of the crewmen being tasked with an insurmountable, premature mission in a dangerously immature aircraft and not "human factors." They feel the fact that another fatal accident occurred later that year and the aircraft had to be grounded for 18 months for further testing and development back up their opinion.

These were experienced pilots who believed in the Osprey project. In the exercise, pilots were to rescue a group of "hostages" and bring them back to base. The task introduced several variables: night flight, a heavy load of Marines and their gear, and a different environment from the coastal one where the pilots had done most of their training. But as the mission unfolded that night in Arizona, not everything went according to plan. A computer malfunctioned in the lead plane, the pilots decided to continue with the exercise and try to reset the computer after landing. As they approached the landing zone, the planes were too high and were hit with an unexpected tailwind. They began a steep descent aiming for the runway - a piece of cake for an experienced military helicopter pilot. The pilots, doing as they were trained, were following the lead plane, but got out of position and tried to manoeuvre back into line. They had little forward airspeed, and the rotors began to stall, losing the lift that holds the aircraft in vertical flight. Just 200 feet above the ground, in a span of about three seconds, the aircraft rolled uncontrollably to the right and turned upside down before slamming into the ground.

The pilots had gotten into an aerodynamic condition called "vortex ring state" or "blade stall." The lead plane may have had the same problem, but it simply landed very hard, crushing the landing gear and skidding several hundred feet and off the runway.

The family feel there were so many factors in the accident that the pilots should exonerated so that the dishonour can be removed.

I think the comments left on the article make some great points:

* "This aircraft was called the widow maker. This Crash was not an isolated incident."

* "Given the many lessons learned from the tragedy that claimed the lives of the aircrew and the passengers, it seems reasonable to assume that had they not been the ones to experience this mishap, another crew and aircraft would have at another time. Clearly none of the pilots involved in the mishap understood the hazards they faced that evening, or both lead and trail aircraft would certainly have gone around for another pass."

* "If Boeing felt compelled to add warning devices to the cockpit to alert pilots, it sounds that the greatest cause of the crash may well have been the initial design. I hope that the powers that be might eventually reconsider."

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