Bunnell, FL, USA
N69EP
Ortmayer/Parson none
While on an instructional flight, a bolt in the main rotor blade broke separating the blade from the hub. The blade struck the student pilot resulting in fatal injuries. The responding FAA inspector stated the on-scene investigation found the hub bar wing and rotor blade had separated from the hub bar due to the failure of the hub bar wing retaining bolt head. The NTSB material lab reported the bolt that retains the hub bar wing to the hub bar was fractured in the radius between the shank and the head. Presence of fatigue arrest marks covering approximately 90 percent of the cross-sectional area. The fatigue cracks initiated from multiple origins all the way around the outer diameter surface at the bases of the radius with the head. The head contacts that hub bar without the use of a washer. A product notice number 33 was issued by Rotary Air Force (RAF) on June 18, 2001, placing a 500 hour time change factor on RAF rotor blades and hub bar "until further notice". The product notice number 33 had not been accomplished on the accident gyroplane at the time of the accident. The owner/certified flight instructor (CFI) stated the blades had a total time of about 930 hours at the time of the accident, which about 430 of those hours were of airtime. He did remember getting some kind of notice through the mail, something about a 500 hours time on the blades but the notice was not clear and too vague. If it was mandatory, a notice wound be issued stating as such. The Owner/CFI added the blades on the accident gyroplane never experience a ground strike, but did have nicks and scrape marks on the blades. A representative of RAF contacted the owner/CFI about a month after product notice 33 was issued advising of the notice and informed him about internal damage and stress that occurs if the rotor blade contacts the ground and the nature of such damage, which are undetectable. The owner/CFI stated he and RAF have had conversations; however, those discussions were more about training issues and the amount of training time the students were receiving. None of those conversations were about RAF product notice number 33 or blade strikes.
On March 12, 2004, about 1830 eastern standard time, an experimental Ortmayer/Parson Gyroplane, N69EP, registered to and operated by a private individual as a Title 14 CFR Part 91 local instructional flight, had a separation of a main rotor blade during a high speed taxi at the Flagler County Airport, Bunnell, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The commercial-rated/certified flight instructor (CFI) pilot received serious injuries and the non-rated student pilot received fatal injuries. The owner/CFI stated he and the student were nearing the completion a flight lesson. Ultralights and gyroplanes use the closed runway at the airport to remain clear of airport traffic. They were practicing flight control coordination while in taxi mode on the ground. At a high speed taxi the nose wheel is off the runway due to the rotor disc is tipped back and the blade speed is increased. At the same time the ground speed does not increase very much. During the high speed taxi, he heard a loud thud and something hit his left side and hand. The engine stopped and they coasted to a stop. The responding FAA inspector stated the on-scene investigation found the hub bar wing and rotor blade had separated from the hub bar due to the failure of the hub bar wing retaining bolt head. (Part Number: AN12-34A). The fractured bolt, nut, and hub bar wing were sent to the National Transportation Safety Board's Materials Laboratory in Washington, D.C. by the FAA. The NTSB Material Laboratory Factual Report states the bolt that retains the hub bar wing to the hub bar was fractured in the radius between the shank and the head. Presence of fatigue arrest marks covering approximately 90 percent of the cross-sectional area. The fatigue cracks initiated from multiple origins all the way around the outer diameter surface at the bases of the radius with the head. The head contacts that hub bar without the use of a washer. The "X" marking and the shank diameter indicate that the bolt was manufacture per military specification AN12. The bolt head had an average macrohardness of 31 HRC. The hardness corresponds to an approximate tensile strength of 146 Ksi, which is above the minimum tensile strength of the 123 Ksi per specification AN12. (Specification AN12 contains a minimum tensile load requirement of 44,000 lbs at root diameter.) The accident gryoplane was built utilizing a Rotary Air Force (RAF) rotor blades and hub bar assembly. A product notice number 33 was issued by RAF on June 18, 2001, stating "a time change factor of 500 hours is being put on the rotor blades and hub bar until further notice." The product notice number 33 had not been accomplished on N69EP at the time of the accident. A RAF representative stated they (RAF) contact customers that utilize RAF products annually with product notices to cover the year development as well if there are any occurrences that require immediate attention. At such time the owners of RAF products are given instruction as per inspections of specific items, replacements required etc. He personally contacted the owner of the accident gyroplane on two occasions to discuss the rotor blades and advised the owner/CFI of product notice number 33. The discussions were about internal damage and stress that occurs if the rotor blade contacts the ground and the nature of such damage. The fact that it cannot be detected and that the rotor blades need to be replaced immediately. The owner was not convinced and continued in spite of the concerns and cautions. The owner/CFI stated to the NTSB that the blades on the gyroplane were the original blades from the time the gyroplane was built. They had a total time of about 930 hours at the time of the accident, which about 430 of those hours were of airtime. He did remember getting some kind of notice through the mail something about a 500 hours time on the blades, but the letter was not clear and too vague. To him it was more of a recommendation, not mandatory. He believed if anything would have developed from that letter, RAF would follow up with a mandatory recall, much like RAF's product notice number 13. He added, the blade on the accident gyroplane never experience a ground strike but did have nicks and scrape marks on the blades. The owner/CFI stated he and the representative of RAF have had conversations; however, those discussions were more about training issues and the amount of training time the students were receiving. None of those conversations were about RAF product notice number 33 or blade strikes. A postmortem examination of the student pilot was performed by Dr. Terrence Steiner, M.D., of District Twenty-three Medical Examiner's Office, located in St. Augustine, Florida. The cause of death was listed as closed head injury. Toxicological analyses of the specimens of the student were obtained by the District Twenty-three Medical Examiner's Office. The FAA Toxicology and Accident Research Laboratory (CAMI) performed analysis of postmortem specimens. The results of analysis by the Medical Examiner's Office were negative for alcohol and drugs. The results of analysis by CAMI were negative for carbon monoxide, cyanide, and volatiles. Ephedrine (not quantified), Pseudoephedrine (not quantified), Dextromethorphan (not quantified) and Dextrorphan (not quantified) was present in the urine specimens. The parts sent to the National Transportation Safety Board's Materials Laboratory in Washington, D.C. by the FAA were returned to the aircraft owner on July 28, 2004.
The owner/pilot mechanic's failure to comply with a manufacture notice to replace the rotor blades and hub bar assembly, resulting in a failure of the hub bar to hub bar wing attaching bolt and separation of a main rotor blade.
Source: NTSB Aviation Accident Database
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