19990221001669A

1968 Bell UH-1H helicopter crashed under unknown circumstances during aerial application. (-23) on February 21, 1999, around 1510 hours PST, a Bell UH-1H helicopter, N6258Z, collided with the ground destroying the a/c and causing serious injury to the pilot. The investigation thus FAR has not revealed any airworthiness related issues which contributed to the accident. The pilot who sustained serious injury during the accident sequence, succumbed to his injuries on February 23, 1999. (.4) the helicopter was in the process of finishing an aerial application run over an almond orchard when it collided with the ground in a nose down attitude. The pilot told the company owner and his family members that the flight controls 'went away' and he could not overpower the flight controls as the helicopter descended. The owner of the helicopter company stated that during the spray run the pilot flew up and over a powerline which was approximately 100 feet from the orchard. He reported that the pilot told him he heard a noise as he flew over the powerlines and then experienced the loss of control. Detailed examination and functional tests of various components of the helicopter's control systems failed to find any evidence of preimpact failure or malfunction. The tail stinger of the helicopter and an exemplar sample of the copper powerline wire was examined in a laboratory and it was determined that there was no wire transfer marks on the tail stinger. The pilot was transported to a hospital after the accident where tests later determined he had fractured his back. He died during a surgical procedure 2 days after the accident. The pilot held an airline transport certificate with over 32,000 hours of flight time, 28,000 of which were in helicopters.