Washington, DC (WBEN) The NTSB has determined the probable cause of the January 2020 crash that claimed the lives of Mark Croce and Michael Capriotto. The NTSB report says the helicopter broke up in-flight.
In a detailed report, the NTSB says on January 9th, Croce and Capriotto were in the helicopter that was flying at an altitude of about 2,300 ft. mean sea level and at an indicated airspeed of about 107 knots, slight pitch and roll oscillations occurred for about 20 seconds followed by a left roll that continued until the helicopter was inverted. "A main rotor blade contacted the tailboom, leading to an in-flight breakup over a residential area," says the report. The NTSB says a post-crash examination showed no evidence of a preimpact failure or malfunction.
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The report says the autopilot was likely engaged when the pitch and roll oscillations started, and might have been the result of the autopilot reacting to an external disturbance, specifically, the moderate-to-severe turbulence that was reported in the area. "Another possible cause of the pitch and roll oscillations was the pilot manually manipulating the cyclic control.
Additionally, an in-flight malfunction of the autopilot’s roll servo actuator could not be ruled out as the source for the pitch and roll oscillations," says the report. The NTSB says none of the scenarios would have precluded the pilot from overriding the autopilot and manually flying the helicopter.
The NTSB says the pilot was not likely impaired or incapacitated by his diagnosed obstructive sleep apnea given the information about his effective continuous positive airway pressure device use. "Also, some or all the ethanol detected in the pilot’s specimens might have been from a source other than ingestion," says the report.
The NTSB's findings of a probable cause are "A severe left roll excursion after the onset of pitch and roll oscillations, which were not arrested by the pilot for to undetermined reasons. This resulted in main rotor blade contact with the airframe and a subsequent inflight breakup of the helicopter."