ERA14FA461 · Eagle R&D Inc HELICYCLE

The private pilot of the experimental amateur-built, single seat, helicopter departed his home airport, flew to a friend's property, and landed uneventfully. After his visit, the pilot started the helicopter, lifted off, and departed to the southwest. About 1 minute later, his friend observed the helicopter coming toward him in a nose-low attitude, about 400 ft above ground level, and at a "high rate of speed." The helicopter suddenly pitched over, began to tumble, and impacted in an inverted attitude; a postcrash fire ensued. Sound spectrum analysis of a video of the accident flight indicated that the helicopter was flying at an airspeed of at least 83 knots when the loss of control occurred.

The pilot did not possess a rotorcraft helicopter rating. Review of the pilot's logbook revealed entries that indicated the pilot had been endorsed for solo flight in the Robinson R22 and had flown an R22 solo. However, according to the flight instructor who had given the pilot about 21 hours of flight instruction in an R22, he had not endorsed the pilot for solo flight in the R22, and he had observed that the pilot had some "bad habits" and would occasionally lose control of the helicopter. It is likely that the pilot made the logbook entries to indicate that he had soloed because they were required by the helicopter kit manufacturer before he could receive a factory checkout of the helicopter, which he had purchased about 6 months before the accident.

The factory checkout was conducted on the day before the accident. According to the factory check pilot, during the checkout, the pilot kept making mistakes and advised the check pilot that he was very tired because he had not slept for 2 days due to anticipation of the checkout. Also, during the checkout, the check pilot determined that the weight and balance of the helicopter was not correct, and the pilot would need to fly the helicopter so they could check the position of the cyclic stick during hover. The pilot advised the check pilot that, because of his lack of sleep and nervousness, he did not feel it safe to fly the helicopter that day. As a result, the check pilot reminded him that he would need to check the weight and balance and the position of the cyclic stick during hover before operating the helicopter, since it was not accomplished that day.

Examination of the wreckage did not reveal evidence of any preimpact failures or malfunctions of the helicopter or engine that would have precluded normal operation. A piece of angle iron was discovered in the debris field, which, according to the pilot's friend, the pilot had attached to the helicopter's tailboom for weight and balance purposes. However, calculations revealed that the helicopter's center of gravity was outside the forward edge of the weight and balance envelope approved by the kit manufacturer. It is likely that the out of balance condition combined with the high speed of the low-altitude pass resulted in the loss of control.

The pilot had therapeutic levels of the antidepressant sertraline in his blood at the time of the accident. Although any psychoactive medications can be impairing, sertraline is not known to directly cause sleepiness or other impairing symptoms. Therefore, it is unlikely that effects from sertraline impaired the pilot. However, sertraline is prescribed for treatment of depression, and major depression itself is associated with significant cognitive degradation, particularly in executive functioning. The cognitive degradation may not improve even with remission of the depressed episode, and patients with severe disease are more significantly affected than those with fewer symptoms or episodes.

The pilot demonstrated poor decision-making and executive function when he decided to fly the helicopter without having soloed in the R22 and without adequately addressing the identified issue with the helicopter's weight and balance. Additionally, flying the helicopter at high speed and low altitude further demonstrated his impaired executive function. One month before the accident, the pilot's personal physician described inappropriate demeanor and unkempt appearance; this is the most recent description of the pilot's executive function and further suggests the depression was not well controlled. Therefore, the pilot's depression and resulting degradation of executive function likely contributed to his decision to fly the poorly balanced helicopter in a high-speed, low-altitude maneuver and contributed to the accident.

The pilot had provided his aviation medical examiner (AME) with a letter from his physician documenting his anxiety/depression as well as its treatment. According to Federal Aviation Administration (FAA) guidance, depression treated for less than 6 months is disqualifying, and a medical certificate should not have been issued. Therefore, the investigation determined the AME failed to follow FAA guidelines for depression and inappropriately provided the pilot with a medical certificate. The AME forwarded the records of the pilot's depression to the FAA 19 days before the accident; therefore, there was insufficient time for the FAA to identify the issue and recall an improperly issued medical certificate.

Additionally, the pilot had used diphenhydramine before the accident. Compared to other antihistamines, diphenhydramine causes marked sedation. Altered mood and impaired cognitive and psychomotor performance may also be observed. The diphenhydramine in cavity blood tested by two laboratories was not consistent (0.828 and 2.171 ug/ml), but the results were well above the therapeutic range of 0.0250 to 0.1120 ug/ml. Diphenhydramine undergoes postmortem redistribution, and postmortem central blood levels may increase by about three times with cavity blood levels even higher. However, even divided by seven or eight, the postmortem levels measured suggest that the pilot likely had impairing levels at the time of the accident. Although the pilot had been able to fly the helicopter for a short distance earlier in the day, the subsequent high-speed pass with the helicopter outside of weight and balance specifications required a much higher degree of flight skill to complete safely. Therefore, the pilot's use of diphenhydramine likely degraded his flight skills and contributed to his inability to safely control the helicopter.

Verbatim NTSB analysis and probable cause from the NTSB dataset