Bell Helicopter Textron Canada 429 N53DE

Summary

On 28 April 2021 at about 17:24 local time, a Bell Helicopter Textron Canada 429 registered N53DE, operated by Duke Energy Business Services LLC, was involved in an accident near Eden, North Carolina, United States. 3 people were on board and one died, 2 were seriously injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

28 April 2021 at 17:24

Classification

Accident

Location

Eden, North Carolina, United States

Coordinates

36.4971, -79.7185

Aircraft

Bell Helicopter Textron Canada 429

Registration

N53DE

Category

Helicopter

Year built

2019

Engines

2

Operator

Duke Energy Business Services LLC

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Danville → Burlington

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

ERA21FA195

1 person died.

The impact of the main rotor blades with the tail boom during low-altitude maneuvers, which severed the tail rotor drive shaft and resulted in a loss of control and impact with terrain.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The helicopter departed and flew cross-country to begin a powerline patrol, which included flying adjacent to powerlines at an altitude of about 100 ft above ground level and with the helicopter gaining altitude during turns and when flying between line inspections. During the final minutes of flight, the helicopter was traveling at an airspeed between 50 and 60 kts along powerlines at an altitude between 700 and 775 ft above mean sea level (msl). As the helicopter flew south, near the end of the north-south powerline’s right of way, the helicopter began a climbing right turn towards the west. A utility lineman in the helicopter’s front left seat recalled that the pilot was reversing course and the helicopter was in a banking turn to the right when he heard a very loud noise, “almost cannon-like, very deep, within a second or two we were heading into the trees.” Onboard data recovered from the helicopter showed rotor speed suddenly increased to 107% about 1.5 seconds before the end of recorded data. Examination of the wreckage showed evidence the main rotor blades impacted the tail rotor drive system. Therefore, it is likely the loud noise heard by the onboard lineman was caused by the main rotor blades impacting the tail rotor drive system, resulting in a severance of the tail rotor drive shaft and subsequently a loss of directional control. Successful recovery of the helicopter after the loss directional control at a low altitude was unlikely and resulted in impact with terrain. Based on analysis of flight data and a scan of the local terrain, it is unlikely the helicopter impacted powerlines or nearby trees at the time the main rotor blades impacted the tail rotor drive system. The loss of clearance between the main rotor and the tail of the helicopter can be caused by sudden aft cyclic control inputs, usually in conjunction with a reduction in collective pitch that would reduce main rotor thrust and increase downward flapping of the blade. The lack of flight control parametric data precluded analysis of flight control inputs at the time the main rotor blade contacted the tail boom. However, it is likely the pilot was not maneuvering to avoid trees based on the increasing distance between the accident helicopter and treetops near the end of the accident flight. Examinations of the helicopter wreckage found no evidence of any preimpact anomalies or malfunctions that would have precluded normal operation of the helicopter.

Quoted verbatim from the NTSB record.