Casualties unknown

1994-05-28: Piper PA-20 (N6174D) — Robert Gaines — Anchorage, AK

Anchorage, AK, US

On May 28, 1994, a Piper PA-20 (registration N6174D) operated by Robert Gaines was involved in an aviation accident near Anchorage, AK. Investigators recorded the probable cause as: The failure of an exhaust valve which was ingested into the cylinder, causing engine damage and forcing a ditching in a swampy area due to limited landing options. 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 pilot was forced to land in a swampy area adjacent to an airport fire station after an exhaust valve failure caused engine damage shortly after takeoff, making a return to the field impossible.

What happened

Shortly after takeoff, the aircraft experienced a critical mechanical failure involving an exhaust valve. The component failed and was subsequently ingested into one of the engine cylinders, causing significant internal damage. The pilot attempted to maintain control but determined that a return to the departure airport was no longer possible due to the extent of the malfunction.

With the airfield out of reach, the pilot sought an alternative landing site. However, options were severely constrained by airport congestion and surrounding buildings, which limited available emergency landing areas. Unable to reach any paved runways or clear zones, the pilot executed a forced landing by ditching the aircraft in a swampy area located adjacent to the airport fire station.

The investigation

The investigation focused on the mechanical failure that precipitated the emergency. Examination of the engine revealed that an exhaust valve had failed during operation. This failed component was ingested into the cylinder, leading to catastrophic internal damage that rendered the engine inoperative or unsafe for continued flight. No other mechanical irregularities were cited as contributing factors.

Findings

The primary factor in this incident was the failure of the exhaust valve and its subsequent ingestion into the engine cylinder. Contributing to the severity of the outcome were environmental and infrastructural constraints at the departure airport. Specifically, airport congestion and nearby buildings restricted the pilot's ability to select a safe landing zone, forcing a ditching in difficult terrain.

Safety message

This incident highlights the critical importance of pre-flight inspections for engine components and the necessity of identifying alternate emergency landing sites during flight planning. Pilots should be aware that mechanical failures can occur rapidly after takeoff, leaving minimal time to identify suitable forced landing areas, particularly in congested airport environments.

Probable cause

The failure of an exhaust valve which was ingested into the cylinder, causing engine damage and forcing a ditching in a swampy area due to limited landing options.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001206X01198. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.