Aviation Accident Summaries

Aviation Accident Summary CEN19LA269

Blair, NE, USA

Aircraft #1

N106PD

Bell 206

Analysis

The pilot-in-command (PIC), who is also a flight instructor and was stationed in the right seat of the helicopter, decided to conduct emergency procedure training with a simulated governor failure of the turboshaft engine before returning to the airport to land. The co-pilot, who is not a flight instructor, was stationed in the left seat.  The intent was to recover from the simulated governor failure at a safe airspeed and altitude. The PIC initiated a simulated governor failure by rolling the throttle down just enough to take the governor offline but still maintain the main rotor rpm in the green (normal) range. The helicopter descended while maintaining airspeed until over the runway. About 40 ft above ground level and about 45 knots, the PIC announced his intention to complete the training maneuver and rolled the throttle back to the full open position. The PIC verbally confirmed the main rotor rpm indication in the green range. All other indications in the helicopter appeared to be normal to the PIC. As the helicopter was in normal operating conditions, the PIC applied aft cyclic to slow down and begin air taxiing to the parking pad to the east (right) of their current position. At that moment, he heard the low main rotor rpm audible horn. The PIC confirmed a loss of engine power by referencing indications in the cockpit. The helicopter descended very rapidly toward the ground and the PIC surmised the engine was unable to produce power. The PIC reduced the collective briefly to regain main rotor energy then applied collective to cushion the landing. The helicopter impacted the runway and came to rest on its left side, which resulted in substantial damage. A postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. Based on the available evidence, the loss of main rotor rpm could not be determined.

Factual Information

On August 16, 2019, about 0945 central daylight time, a Bell 206B helicopter, N106PD, sustained substantial damage when it was involved in an accident near Blair, Nebraska. The two commercial pilots sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations public aircraft flight. According to the Omaha Police Department Air Support Unit, the helicopter departed Blair Municipal Airport (BTA), Blair, Nebraska, for a patrol flight over Omaha, Nebraska. After about 1 hour of flight, the helicopter headed back to BTA. About 4 miles south of runway 31 at BTA, the pilot-in-command (PIC), who is also a flight instructor and was stationed in the right seat, decided to conduct emergency procedure training with a simulated governor failure of the turboshaft engine prior to landing back to the airport. The co-pilot, who is not a flight instructor, was stationed in the left seat. Since a training event was being conducted, the intent was to recover from the simulated governor failure at a safe airspeed and altitude before executing a normal landing. The PIC initiated a simulated governor failure by rolling the throttle down just enough to take the governor offline, but still maintaining the main rotor rpm in the green (normal) range. The helicopter descended while maintaining airspeed until over the runway. About 40 ft above ground level and about 45 knots, the PIC announced his intention to complete the training maneuver and rolled the throttle back to the full open position. The PIC confirmed the main rotor rpm indication in the green range, which he verbally announced. All other indications in the helicopter appeared to be normal to the PIC. As the helicopter was in normal operating conditions, the PIC applied aft cyclic to slow down and began air taxiing to the parking pad to the east (right) of their current position. At that moment, he heard the low main rotor rpm audible horn. The PIC confirmed a loss of engine power by referencing indications in the cockpit. The helicopter descended very rapidly toward the ground and the PIC surmised the engine was unable to produce power. The PIC reduced the collective briefly to regain main rotor energy and then applied collective to cushion the landing. The helicopter impacted the runway and came to rest on its left side. The PIC reported it was unknown if the engine was stilling running after the helicopter came to rest. The PIC executed an emergency shutdown and both pilots egressed from the helicopter without further incident. The helicopter sustained substantial damage to the main rotor system, the fuselage, the tailboom, and the tail rotor system. A postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. A review of the helicopter's maintenance records revealed no evidence of any uncorrected discrepancies with the airframe and engine.

Probable Cause and Findings

The loss of main rotor rpm for reasons that could not be determined based on the available evidence, which resulted in a hard landing.

 

Source: NTSB Aviation Accident Database

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