Tuesday, April 10, 2012

NTSB: Pilot overwhelmed by g-forces in Reno crash

The pilot of the P-51 Mustang that crashed at an air show in Nevada last September experienced overwhelming g-forces during the onset of the incident, and was incapacitated almost instantly, the National Transportation Safety Board said Tuesday.

The NTSB said the pilot experienced more than 9 g's of force -- meaning nine times the force of gravity -- which is well beyond the ability of the human body to remain conscious. The force deformed the plane's fuselage, forced the tail wheel to deploy and likely resulted in the plane's trim tab -- a piece of the plane's tale -- to fly off the aircraft, the safety board said.

The pilot of the Galloping Ghost and 10 spectators were killed in the September 16 crash. In addition, more than 60 spectators were injured.
The safety board released details on the crash at a news conference in Reno, but said it would be months before it determines the probable cause of the accident. Nonetheless, the board issued a number of recommendations it said should make conditions safer before the next Reno Air Race scheduled in September.

Foremost among the recommendations: the NTSB said all of the unlimited class aircraft like the P-51 Mustang should be made to demonstrate their airworthiness before participating in a public air race.

The P-51 aircraft, The Galloping Ghost, was flying the fastest it had ever flown on the Reno course since the plane had been modified in 2009, the safety board said.

"This pilot, in this airplane, had never flown this fast on this course," said NTSB chairwoman Deborah Hersman.

Tuesday's news conference also cast strong doubt on at least two widely-held beliefs about the accident.
The first was that 74-year-old pilot Jimmy Leward took desperate, last-minute actions to avoid hitting the crowds in the grandstands. The NTSB said that Leward was likely incapacitated in the first second of the accident sequence. The plane experienced g-forces exceeding the 9-g limit of the plane's accelerator, Hersman said. It is difficult for trained pilots to remain conscious with even 5 g's, Hersman said.

Photos show the pilot is not visible in the canopy just two seconds into the accident sequence, and is seen bent forward and leaning to the right in a later photo, Hersman said, indicating he lost consciousness early in the mishap.

Tuesday's news conference also refuted theories that the loss of the plane's trim tab caused the plane crash. Photos show the trim tab departing the plane six seconds after the accident sequence began, meaning its departure was likely a result of the mishap, not its cause.

Hersman noted that the aircraft was highly modified to improve its speed. Its 37-foot wingspan had been reduced to 29 feet.

A lot of work remains to be done before the safety board rules on the probable cause of the accident, Hersman said.

"This is an ongoing investigation," she added. "What we're seeing is a lot of very heavy forces on this aircraft and this pilot and what we're working on now is what precipitated that."

NTSB Identification: WPR11MA454
14 CFR Part 91: General Aviation
Accident occurred Friday, September 16, 2011 in Reno, NV
Aircraft: NORTH AMERICAN/AERO CLASSICS P-51D, registration: N79111
Injuries: 11 Fatal,66 Serious.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On September 16, 2011, about 1626 Pacific daylight time, an experimental North America P-51D, N79111, impacted terrain following a loss of control while maneuvering at Reno Stead Airport, Reno, Nevada. The airplane was registered to Aero-Trans Corp, Ocala, Florida, and operated by the pilot as Race 177 under the provisions of 14 Code of Federal Regulations Part 91. The commercial pilot sustained fatal injuries; the airplane sustained substantial damage. Casualties on the ground included 10 fatalities and 74 injured. As of the time of this preliminary report, eight of the injured remain hospitalized, some in critical condition. Visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed for the local air race flight, which departed from Reno Stead Airport about 10 minutes before the accident.

The airplane was participating in the Reno National Championship Air Races in the last event of the day. The airplane had completed several laps and was in a steep left turn towards the home pylon when, according to photographic evidence, the airplane suddenly banked momentarily to the left before banking to the right, turning away from the race course, and pitching to a steep nose-high attitude. Witnesses reported and photographic evidence indicates that a piece of the airframe separated during these maneuvers. After roll and pitch variations, the airplane descended in an extremely nose-low attitude and collided with the ground in the box seat area near the center of the grandstand seating area.

Investigators from the National Transportation Safety Board (NTSB) and the Federal Aviation Administration examined the wreckage on site. They documented the debris field and identified various components of the airplane’s control system and control surfaces. The wreckage was removed to a secure storage facility for detailed examination at a later date.

The airplane’s ground crew noted that the airplane had a telemetry system that broadcast data to a ground station as well as recorded it to a box on board the airplane. The crew provided the ground station telemetry data, which includes engine parameters and global positioning satellite system data to the NTSB for analysis. The onboard data box, which sustained crush damage, was sent to the NTSB’s Vehicle Recorder laboratory for examination. Investigators recovered pieces of a camera housing and multiple detached memory cards from the airplane’s onboard camera that were in the debris field. The memory cards and numerous still and video image recordings were also sent to the Vehicle Recorders laboratory for evaluation.

The Federal Aviation Administration and the Reno Air Race Association are parties to the investigation.

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