NTSB Identification: ERA13FA070
14 CFR Part 91: General Aviation
Accident occurred Friday, November 30, 2012 in Apollo Beach, FL
Probable Cause Approval Date: 02/04/2014
Aircraft: ROBINSON HELICOPTER R22 BETA II, registration: N2626N
Injuries: 1 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 helicopter was in cruise flight about 500 feet above ground level, over a bay beach, when both of its main rotor blades separated. The helicopter subsequently descended into the bay, and the wreckage with the exception of the main rotor blades was recovered 2 days later. One main rotor blade was subsequently recovered about 1 month later, and the other main rotor blade was not recovered. With the exception of the separation of the main rotor blades, examination of the airframe and engine did not reveal any evidence of preimpact mechanical malfunctions or anomalies. Metallurgical examination of the rotor hub and the recovered main rotor blade revealed features consistent with overstress, and no preexisting cracking or fatigue was noted. Additionally, damage to the teetering stops on the rotor hub was consistent with mast bumping. The observed mast bumping could have resulted from large, abrupt flight control inputs or from a mechanical failure of the unrecovered main rotor blade.

Toxicological testing and review of the pilot's medical records revealed a history of near nightly use of zolpidem (Ambien) as a sleep aid and frequent use of rizatripan (Maxalt) to treat migraine headaches. Neither condition or its respective prescription medication for treatment was reported to the Federal Aviation Administration and if it had been, would have most likely disqualified the pilot for a medical certificate based on the frequency of use/symptoms; however, the investigation could not determine the effects, if any, that the recurrent migraine, chronic zolpidem use, and underlying sleep problems might have had on the pilot at the time of the accident.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

Mast bumping for reasons that could not be determined because one main rotor blade was not recovered.

Full narrative available

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