Loss of control Accident Robinson R22 Beta II N923SH,
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ASN Wikibase Occurrence # 216368
 
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Date:Wednesday 17 October 2018
Time:14:21
Type:Silhouette image of generic R22 model; specific model in this crash may look slightly different    
Robinson R22 Beta II
Owner/operator:Spitzer Helicopter LLC opb Helisat LLC
Registration: N923SH
MSN: 3864
Year of manufacture:2005
Total airframe hrs:6455 hours
Engine model:Lycoming O-360-J2A
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Destroyed
Category:Accident
Location:Fulton, MO -   United States of America
Phase: En route
Nature:Training
Departure airport:Moscow Mills, MO (None)
Destination airport:Columbia Regional Airport, MO (COU/KCOU)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The pilot was conducting a solo cross-country flight in the helicopter as part of his instruction to obtain his rotorcraft rating. The intent of the flight was to fly solo cross-country to perform touch and go landings at another airport. About 36 minutes after departing on the flight, the helicopter impacted terrain. One witness reported that he saw the helicopter flying and heard the engine stop. He stated that the helicopter began to lose altitude and began to spin in a downward spiral. Another witness reported that he observed the helicopter flying toward him with its nose pointed downward about 45°. He stated that the blades were turning slowly and that the helicopter was making a circular motion along its axis, but not a spiral, as it flew toward the ground.

The helicopter impacted terrain in a nose-low, left-skid-down attitude. Examination of the airframe and engine did not reveal any mechanical pre-impact anomalies. The main rotor blade damage was consistent with low rotor rpm at the time of impact, and the low rotor rpm caution light filament was stretched, consistent with the light being illuminated at the time of impact. Examination of the rotating engine components did not reveal any evidence consistent with rotation at the time of impact. The carburetor heat control in the cockpit was found unlocked and found in the "on" position. According to a carburetor icing probability chart, the atmospheric conditions about the time of the accident were conducive to moderate icing at cruise power settings and serious icing at descent power settings. Thus, it is likely that the helicopter experienced a loss of engine power due to carburetor ice accumulation. Although the carburetor heat was found in the on position, it is likely that the pilot applied the carburetor heat to address the loss of engine power but it was too late and at too low an altitude to restore engine power.

Following the loss of engine power, the main rotor rpm would have rapidly begun to deteriorate unless the pilot immediately reduced collective and entered an autorotation. Given the signatures of low rotor rpm present at the site, it is likely that the pilot failed to initiate the autorotation in a timely manner, which allowed the main rotor rpm to deteriorate to the extent that the main rotor stalled and the pilot would be unable to recover.

Probable Cause: A total loss of engine power due to carburetor icing, the pilot's delayed application of carburetor heat, and the pilot's delay in entering an autorotation following the loss of engine power, which resulted in a main rotor stall due to low rotor rpm and an uncontrolled descent into terrain.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: CEN19FA009
Status: Investigation completed
Duration:
Download report: Final report

Sources:

NTSB

Location

Revision history:

Date/timeContributorUpdates
17-Oct-2018 22:32 Geno Added
18-Oct-2018 17:19 Geno Updated [Aircraft type, Registration, Cn, Operator, Source, Damage, Narrative]
20-Mar-2019 16:04 Dr. John Smith Updated [Time, Operator, Location, Phase, Nature, Departure airport, Destination airport, Source, Narrative]
14-Mar-2021 01:24 Captain Adam Updated [Operator, Location, Source, Damage, Narrative]
06-Mar-2022 23:29 Captain Adam Updated [Departure airport, Narrative, Category]

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