Casualties unknown

Left Engine Fails After Departure, Lands Safely; Turbine Disk Rupture Found (N666K)

Nantucket, MA, US

On September 26, 1999, an Israel Aircraft Industries 1124 (registration N666K) was involved in an aviation accident near Nantucket, MA. Investigators recorded the probable cause as: High cycle fatigue failure of the first stage low-pressure turbine disk originating from a subsurface location. 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 2026-06-10Data APIEditorial standards

After departure, a left engine failed. The aircraft landed uneventfully. Examination revealed a ruptured first stage low-pressure turbine disk due to high cycle fatigue from a subsurface origin.

Incident Overview

Following departure, the left engine experienced a failure. The flight crew completed the engine securing procedures, and the aircraft landed without further incident.

Damage Examination

Inspection of the aircraft showed extensive damage to the left engine nacelle and turbine section. The first stage low-pressure turbine (LPT) rotor disk had separated from the low-pressure turbine shaft and penetrated the inner stage transition liner. The engine was removed and disassembled, revealing that the first stage LPT had a piece of the web and rim missing outboard of the curvic coupling.

Metallurgical Findings

Metallurgical examination of the ruptured first stage LPT disk identified a high cycle fatigue failure originating from a subsurface location. The disk's dimensions adjacent to the fracture and its material properties were found to conform to engineering specifications.

Probable cause

High cycle fatigue failure of the first stage low-pressure turbine disk originating from a subsurface location.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X19855. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.