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Casualties unknown

Helicopter Rotor Strikes Tail Boom During Post-Flight Cooldown (N7535S)

Woodward, OK, US

On April 13, 2005, a Robinson R44 II (registration N7535S) was involved in an aviation accident near Woodward, OK. Investigators recorded the probable cause as: the pilot's encounter with adverse weather conditions. 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 2026-07-04Data APIEditorial standards

After landing, a pilot performed cooldown procedures and shut down the engine. While applying the rotor brake, a wind gust caused the rotor to lift and strike the tail boom.

Accident Sequence

A pilot with 10,500 hours of flight experience landed a single-engine helicopter on a portable helipad and began cooldown procedures. After sufficient time, the pilot disengaged the clutch, waited 30–45 seconds, and then turned the engine off. The cyclic was locked in the center position, the clutch light went out, and the rotor was winding down slowly.

As the pilot reached back to apply the rotor brake, a strong wind gust caused the rotor to lift and strike the tail boom. At the time of rotor blade impact, the engine was turned off and the clutch was totally disengaged.

Wind Conditions

The reported wind at the time of the accident was from 350 degrees at 11 knots, gusting to 15 knots.

Weather

Frequently asked questions

What happened in the 13 Apr 2005 Robinson R44 II accident near Woodward, OK?

After landing, a pilot performed cooldown procedures and shut down the engine. While applying the rotor brake, a wind gust caused the rotor to lift and strike the tail boom.

What aircraft was involved and where did it happen?

The accident on 13 Apr 2005 involved a Robinson R44 II, registration N7535S, at Woodward, OK.

What was the probable cause of the accident?

the pilot's encounter with adverse weather conditions.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20050510X00585. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.