Tuesday, May 7, 2013
Improving Search And Rescue
Enhanced technology is available, but aviators have been slow to adopt it
Twelve days after the accident, the pilot of the aircraft walked into a cafe in the town of Olancha in the Owens Valley. After having something to eat and phoning relatives, the pilot contacted the Inyo County Sheriff's Department, reported that he was involved in an aircraft accident in the mountains and that his two passengers were still at the aircraft.
A sheriff's deputy and a pilot took the accident pilot on a flight to find the accident site by retracing the route the pilot said he walked along to reach the cafe. This attempt was unsuccessful. The pilot was next flown down to the area of the Kernville Airport, and he was able to orient himself and retrace the accident flight up the Kern River Valley to the crash site. A U.S. Navy helicopter responded to the crash site and found both passengers dead.
Investigators noted that while documents showed a portable ELT was installed in the aircraft, a fixed ELT by a different manufacturer was found in the wreckage. Both ELTs were approved for installation in the airframe under the type certificate. No documentation was found dealing with the removal of the factory-supplied ELT and the installation of the different ELT.
The unit, which was found in the wreckage, was mounted under the left front seat. According to installation instructions, a coaxial antenna cable was supposed to be routed under the carpet to the left front door post, then up the post to the left wing root and to the external antenna. The external antenna was supposed to be mounted on the metal wing root fairing.
After recovery of the aircraft, the airframe was examined for evidence of the external ELT antenna installation under the approved Maule type certificate drawings. No evidence of a coaxial cable installation was found. Furthermore, the wing root fairings showed no evidence that an external antenna had ever been mounted there. The ELT switch was found in the "off" position.
The pilot told investigators that he was flying at 12,000 feet MSL over the high terrain and, when nearing the accident site, the aircraft suddenly rolled and yawed to the right in very strong turbulence. The pilot said he had the impression that the aircraft was being pushed forward and down toward the ground by some strong force.
With the aircraft descending, the pilot managed to resume level flight just before hitting the trees. The NTSB determined that the probable cause of the accident was the pilot's entry into a box canyon at an altitude insufficient to maintain clearance from the surrounding terrain and obstacles. Factors in the accident were the high-density altitude and the steep, rapidly rising nature of the mountainous terrain.
Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board.
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