NTSB Identification: DEN02LA103.
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Accident occurred Sunday, September 08, 2002 in Mead, CO
Probable Cause Approval Date: 04/01/2003
Aircraft: Adler SA-1, registration: N551SA
Injuries: 1 Fatal.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
Witnesses observed "a rotor or a wing" separate from the gyroplane, and the gyroplane then descended and impacted terrain.
According to the deputy's report, a rotor blade was found about 150 feet north of the point of impact, and other debris was strewn to the southwest. The co-builder of the accident gyroplane, who was also a close friend of the pilot, contacted three gyroplane experts: the designer of the SA-1 Dominator and President of Rotor Flight Dynamics; a gyroplane aerodynamist; and the designer of another gyroplane. They examined the wreckage and compiled both a factual and analytical report. The following is based on the factual portion of the report. The separated rotor blade was bowed upward and had fractured about 2 feet from the tip. The fracture was consistent with positive overload. There was orange paint and primer transfer marks on the top and upper leading edge (the tail cone was painted orange). The attached rotor blade was also bent upward. The propeller blades exhibited no strike marks. The rotor head and hub bar were intact. The hub bar, normally bent 2.5 degrees upward, was bent approximately 10 degrees upward. The roll pillow blocks bore evidence of hammering and were mushroomed. The pitch stops were similarly damaged. In the analytical portion of the report, the necessity of maintaining blade loading at all times in order to maintain main rotor blade rotation was noted. The fracture on the separated main rotor blade was in "a purely upward bending moment which could only have occurred if the blade rpm had dramatically slowed...If totally unloaded, the blade rpm can deteriorate as fast as 120 rpm/sec." Normal rotor blade rpm is 320 to 400 rpm. If rotor blade rpm were allowed to drop, increasing the velocity of air moving through the rotor system, severe blade "flapping" would result as evidenced by the pounding and mushrooming of the roll pillow blocks and bending of the hub bar on the rotor head. A toxicological test revealed 2.024 (ug/mL, ug/g) paroxetine in the blood and liver. The drug is an antidepressant and contraindicated for flight. The pilot's personal physician prescribed the drug for the treatment of fibromyalgia, a condition manifested by muscle soreness. Adverse effects of the drug include drowsiness, muscle weakness, agitation, and tremors.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the pilot's failure to maintain main rotor rpm, resulting in blade flapping, subsequent blade contact with the airframe, and loss of control. Full narrative available
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