Casualties unknown

2003-04-02: Hughes 369D (N56SM) — Estes Park, CO

Estes Park, CO, US

On April 2, 2003, a Hughes 369D (registration N56SM) was involved in an aviation accident near Estes Park, CO. Investigators recorded the probable cause as: the failure of the pilot-in-command to maintain clearance from terrain. Factors include the high density altitude and the pilot-in-command's improper in-flight planning. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A helicopter involved in capturing bighorn sheep with a net cannon lost rotor speed while pursuing animals uphill, struck the ground, broke its right skid, rolled over, and shed its main rotor blades. Density altitude was 13,068 feet.

Incident Overview

A helicopter operating in a wildlife management role experienced an accident while attempting to capture bighorn sheep using a net cannon. The pilot reported that the aircraft was in pursuit of a group of animals across rising terrain.

Sequence of Events

According to the pilot's account, the helicopter was following a herd of bighorn sheep up a slope at an elevation of 11,200 feet. During the pursuit, the rotor speed began to decline. The pilot attempted to execute a turn to reverse direction, but the helicopter made contact with the ground. The impact broke the right skid of the landing gear. Subsequently, the helicopter rolled onto its right side, and the main rotor blades detached from the rotor hub.

Environmental Conditions

At the time of the accident, the density altitude was calculated to be 13,068 feet. This value indicates the altitude at which the air density would correspond to standard atmospheric conditions, reflecting the reduced performance capability of the helicopter at high elevations and temperatures.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20030409X00465. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.