NTSB Identification: DEN03FA034.
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Accident occurred Thursday, January 16, 2003 in Midway, UT
Probable Cause Approval Date: 11/25/2003
Aircraft: Yakovlev YAK 52, registration: N2256J
Injuries: 2 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The purpose of the flight was for one pilot to familiarize the other pilot with the YAK 52. Both were retired military pilots and airline captains. The fixed base operator's (FBO) receptionist heard a voice on the Unicom frequency say, "We're crashing, we're going in," or words to that effect. Witnesses saw the airplane descend vertically and impact an open field in a residential area. They said the engine was developing full power. During wreckage examination, a brass nut was found in the crushed skin of the empennage. The nut was identified as coming from an air hose assembly. Many of the airplane's systems were pneumatically operated (i.e., engine start, flaps/landing gear extension/retraction). On one end of the assembly was a brass adapter that consisted of a nut and fitting. According to a partner of Squadron 52 LLC, the adapter portion of the assembly was always connected to, and was an integral part of, the hose assembly. Although not normally carried in the airplane, an air hose assembly was usually carried on cross-country trips in the event the air tank developed a leak and there was insufficient pressure to start the engine. The hose assembly could be attached to an FBO's air bottle and the engine could be "jump started." The nut exhibited numerous gouges. The nut was placed between the elevator bellcrank and housing. When the bellcrank was moved by hand, full up and down elevator control could not be achieved because to the impeding nut. The gouges on the nut were consistent with elevator bellcrank contact. Scrape marks were also noted on the underside of the bellcrank housing. It could not be determined how or when the adapter assembly separated from the hose, or how the nut got into the empennage.
This report was modified on July 29, 2004.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The malfunction of the elevator control as a result of a jammed elevator control bell crank, rendering control of the airplane impossible. A contributing factor was the foreign object (nut) damage. Full narrative available
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