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ASN Wikibase Occurrence # 169496
Last updated: 30 November 2019
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Type:Silhouette image of generic UH1 model; specific model in this crash may look slightly different
Bell HH-1H
Owner/operator:Las Vegas Metropolitan Police Department
Registration: N233JP
C/n / msn: 70-2478
Fatalities:Fatalities: 1 / Occupants: 6
Aircraft damage: None
Location:near Mount Charleston, NV -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Departure airport:North Las Vegas, NV (VGT)
Destination airport:North Las Vegas, NV (VGT)
Investigating agency: NTSB
The purpose of the flight was to rescue a stranded hiker from the side of the mountain in dark night conditions. Once on scene, the pilot, copilot, hoist operator, and two rescue crewmembers briefed that one of the rescue crewmembers would be lowered down to the hiker and that he would then help the hiker into the strop harness. The rescuer was to remain attached to the hoist hook that was attached to his sit harness via a carbineer throughout the rescue operation, which was planned to take about 30 seconds. The hoist hook had three attachment points: a main hook, a secondary hook, and a utility eye; it is likely that the rescuer’s sit harness was attached to the main hook and that the strop harness was attached to the utility eye.
The hoist operator reported that, after the rescuer was lowered down to the hiker, he observed the rescuer helping the hiker into the strop harness. The hoist operator then told the pilot that he would be cleared to move the helicopter to the left and aft to clear the rock face as soon as he ”had the load.” The hoist operator added that he saw the rescuer signal to begin the hoisting operation.
The hiker reported that the rescuer put him into the harness while remaining attached to the hoist hook. He stated that the rescuer was moving purposefully and that his actions appeared very deliberate. The rescuer then told him to stand up, and he heard what he thought was the sound of a carabineer unclipping. It is likely that the rescuer’s carabineer inadvertently became disengaged or partly disengaged from the hoist hook at this point. As the cable started moving upward, the hiker then noticed that the rescuer began rushing his actions, likely indicating that the hoist operation had begun before the rescuer was ready. As the hook was ascending, the rescuer grabbed both of the hiker’s hands and placed them on the harness just below the hoist hook, which was at the hiker’s eye level, and told to the hiker to hold on.
During a rescue using a strop harness, the rescuer is supposed to leave the ground first. However, the hiker reported that his feet left the ground first while the rescuer remained on the ledge. The hiker then started to rotate and move away from the rock face. While moving away from the rock face, the hiker felt the rescuer grab him around his waist and then slide down his body until the rescuer fell, which resulted in his death. The hiker was hoisted into the helicopter and was uninjured.
Examination of the harness and hoist hook revealed no damage that would have precluded normal operation. The hoist’s main and secondary hooks did not have self-locking safety mechanisms; this design could allow a carabineer to travel upward against the hoist hook’s nonlocking safety latch and inadvertently disengage the hook. Given the hiker’s statement about hearing a carbineer unclipping and the rescuer’s subsequent fall, it is likely that the hoist hook inadvertently disengaged from the rescuer’s harness.
The helicopter was not equipped to allow direct intercommunications between the hoist operator and the rescuer. Therefore, once the rescuer departed the helicopter, the only effective communication between the hoist operator and the rescuer was hand signals. Although the hoist operator was using night vision goggles during the flight, the dark night conditions likely limited his detail vision and made it difficult to see the rescuer’s hand signals. The lack of direct audio communications between the hoist operator and the rescuer prevented the rescuer from being able to report a problem after the hoist operation began and might have contributed to the hoist activation occurring before the rescuer was ready.

Probable Cause: The premature hoisting operation and the inadvertent disengagement of the hoist hook on the rescuer’s harness in dark night conditions. Contributing to the accident was a lack of direct audio communication between the rescuer and the hoist operator.



Revision history:

03-Sep-2014 08:43 Aerossurance Added
03-Sep-2014 19:26 Aerossurance Updated [Source]
23-Sep-2016 18:59 Aerossurance Updated [Location]
21-Dec-2016 19:28 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
29-Nov-2017 08:51 ASN Update Bot Updated [Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative]

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