Friday, March 18, 2022

Hughes 500 Defender, N500MZ: Accident occurred March 17, 2022 in De Soto, Dallas County, Iowa

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office;  Ankeny, Iowa
MD Helicopters; Mesa, Arizona 
Rolls-Royce; Indianapolis, Indiana

Winco Inc

Location: De Soto, Iowa
Accident Number: CEN22LA146
Date and Time: March 17, 2022, 14:30 Local 
Registration: N500MZ
Aircraft: Hughes 500D
Injuries: 1 Minor
Flight Conducted Under: Part 133: Rotorcraft ext. load

On March 17, 2022, about 1430 central daylight time, a Hughes 500D, N500MZ, was substantially damaged when it was involved in an accident near De Soto, Iowa. The commercial pilot sustained minor injury. The helicopter was operated as a Title 14 Code of Federal Regulations Part 133 external load flight.

The mechanic reported that on March 5, 2022, the current engine was installed in the helicopter and that the work was performed in accordance with the Rolls-Royce M250-C20 Series Operation and Maintenance Manual. The engine had arrived with all the accessories
previously installed except for the starter generator. The tach generators, fuel control, governor, fuel nozzle, and bleed valve were already installed before they received the engine. The helicopter had several abnormal starts after the installation work and the maintenance team kept troubleshooting the abnormal starts.

On March 16, 2022, the fuel control was removed from the previously removed engine and was installed on the current engine for troubleshooting purposes. After the fuel control was installed, the fuel system was purged of air, a leak check was performed, and a ground run was performed.

On the day of the accident, the pilot performed a fuel sample check and the preflight checks with no anomalies noted. The pilot aborted the first start due to a high turbine outlet temperature (TOT). The mechanic adjusted the acceleration settings, and the second start was within TOT limitations. The pilot then departed for the landing zone.

During longline operations, and while flying to a structure, the helicopter sustained a partial loss of engine power. The helicopter was at 90ft agl and about 30 kts, and the pilot lowered the collective to enter an autorotation. He was unable to point the helicopter into the wind because a powerline was in the direction of the wind, so there was 20kt crosswind from the north (his left side). At that altitude and speed, the pilot was unable to build much inertia in the main rotor system, and the helicopter impacted a muddy grass hill. The helicopter came to rest on its right side. After the helicopter came to rest, the pilot noticed the engine was still, “at a slow run, less than idle.” The pilot performed an emergency shutdown and was able to egress from the helicopter without further incident. 

The helicopter sustained substantial damage to the fuselage, the main rotor system, and the tail rotor system. The helicopter was recovered from the accident site for a future examination of the airframe and the engine. During the recovery from the field, it was noticed by the operator that an airline on the governor to the fuel control was found not attached, via the b-nut. It appeared the b-nut had backed away to the elbow of the line. The Rolls-Royce M250-C20 Series Operation and Maintenance Manual provides a warning that states:

Failure to properly install, align, and tighten fuel, oil, and air fittings and tubes could result in an engine failure.

Aircraft and Owner/Operator Information

Aircraft Make: Hughes 
Registration: N500MZ
Model/Series: 500D 
Aircraft Category: Helicopter
Amateur Built:
Operating Certificate(s) Held: Rotorcraft external load (133), Agricultural aircraft (137)
Operator Designator Code:

Meteorological Information and Flight Plan

Conditions at Accident Site: VMC
Condition of Light: Day
Observation Facility, Elevation: KDSM, 963 ft msl 
Observation Time: 13:54 Local
Distance from Accident Site: 19 Nautical Miles
Temperature/Dew Point: 7°C /6°C
Lowest Cloud Condition: Few / 1000 ft AGL  
Wind Speed/Gusts, Direction: 14 knots / , 10°
Lowest Ceiling: Broken / 7000 ft AGL 
Visibility: 7 miles
Altimeter Setting: 29.96 inches Hg
Type of Flight Plan Filed: None
Departure Point: De Soto, IA 
Destination: De Soto, IA

Wreckage and Impact Information

Crew Injuries: 1 Minor
Aircraft Damage: Substantial
Passenger Injuries: 
Aircraft Fire: None
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 1 Minor 
Latitude,  Longitude: 41.561048,-94.070565 (est)

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