Sikorsky S61 accident near Camp Dwyer, OF
On April 20, 2020, a Sikorsky S61 (helicopter) was involved in an accident near Camp Dwyer, OF. 3 people were seriously injured. Damage to the aircraft: substantial.
- Date
- April 20, 2020
- Place
- Camp Dwyer, OF
- Aircraft
- Sikorsky S61 · Helicopter
- Injuries
- 0 fatal, 3 serious, 0 minor
- Damage
- Substantial
- Position
- 30.116°N, 64.071°E
- NTSB ID
- 20200422X94542
Official records · DCA20LA100
- Public docket: reports, statements and exhibits from the investigation
NTSB summary
HISTORY OF FLIGHTOn April 20, 2020, about 0802 local time, a Sikorsky S-61N, N908CH, entered an uncommanded left yaw while approaching Camp Dwyer, Afghanistan. The flight crew made an emergency landing, during which the helicopter impacted the ground and rolled on its right side. The two pilots and the crew chief aboard the helicopter were seriously injured, and the helicopter sustained substantial damage. The flight was operated by Construction Helicopters Incorporated, doing business as CHI Aviation, under the provisions of Title 14 Code of Federal Regulations Part 135 and a contract with the US Department of Defense. In accordance with Annex 13 to the International Civil Aviation Organization, the National Transportation Safety Board (NTSB) accepted delegation of this accident investigation from the Afghanistan Civil Aviation Authority. The purpose of the flight was to transport cargo from Camp Bastion (also in Afghanistan) to Camp Dwyer. The helicopter was installed with a cockpit voice recorder (CVR), which showed that, at 0746:13, the right seat pilot called, “Dwyer’s in sight,” which the left seat pilot acknowledged. The helicopter was also equipped with an Appareo Vision 1000 image recorder, which was installed on the ceiling of the cockpit. The image recorder was forward looking with a full view of the instrument panel, a partial view of the left and right seat cockpit controls, and a partial view of the outside via the lower portion of the windscreen. The accident recording consisted of parametric data, still images, and audio. The image recorder transcription beg
Probable cause
Fatigue cracking of the auxiliary servo cylinder’s pedal damper check valve housing and its bolts, which caused the sudden and uncommanded movement of the helicopter’s left pedal and a subsequent left yaw that continued until ground impact. Contributing to the accident were (1) the nonconforming edge of the pedal damper check valve housing during manufacture and (2) Sikorsky’s lack of a specific i
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Browse: Afghanistan · Sikorsky aircraft
Source: NTSB aviation accident database (US government, public domain). Findings may be preliminary or later revised by the NTSB. Not a complete global record.
