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Helicopter Damaged During Autorotation After Engine Power Loss (N51763)

Castle Rock, CO, US

On July 3, 1996, an Enstrom 280C (registration N51763) operated by Denver Helicopters, Inc. was involved in an aviation accident near Castle Rock, CO. No fatalities were reported. Investigators recorded the probable cause as: Total failure of the magneto. A factor was the pilot operating the helicopter with a known deficiency. 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

A helicopter sustained substantial damage during a run-on landing following an engine power loss. Postaccident testing revealed a magneto malfunction with no spark from any of the 12 leads.

Incident Overview

A helicopter experienced a loss of engine power, prompting the pilot to perform an autorotation. The subsequent run-on landing on a rough field resulted in substantial damage to the aircraft.

Postaccident Findings

After the accident, testing of the magneto showed that when rotated, none of the 12 leads produced a spark. Inspection of the distributor cap revealed that none of the points opened during rotation of the magneto, indicating a malfunction within the ignition system.

Prior Indications

An FAA inspector had heard the engine running roughly on the day before the accident. The inspector advised the pilot to have the engine inspected before further flight. In response, the pilot stated that such a condition was 'common on Enstrom helicopters when the engine is hot.'

Frequently asked questions

What happened in the 3 Jul 1996 Enstrom 280C accident near Castle Rock, CO?

A helicopter sustained substantial damage during a run-on landing following an engine power loss. Postaccident testing revealed a magneto malfunction with no spark from any of the 12 leads.

Were there any fatalities in the 3 Jul 1996 Enstrom 280C accident?

No fatalities were recorded in this accident.

What aircraft was involved and where did it happen?

The accident on 3 Jul 1996 involved an Enstrom 280C, registration N51763, operated by Denver Helicopters, Inc., at Castle Rock, CO.

What was the probable cause of the accident?

Total failure of the magneto. A factor was the pilot operating the helicopter with a known deficiency.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001208X06213. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.