Casualties unknown

Helicopter In-Flight Break-Up Traced to Swashplate Pin Fatigue Fracture (N30SV)

Spencer, IA, US

On August 21, 1998, a Bell 222 (registration N30SV) was involved in an aviation accident near Spencer, IA. Investigators recorded the probable cause as: Fatigue fracture of the white swashplate outer ring pin due to an insufficient interference fit between the outer swashplate bores and the outer diameter of the swashplate ring pins. 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

A helicopter broke up in flight near Spencer, Iowa, at 130 knots and 960 feet. Examination revealed a fatigue fracture in a swashplate pin caused by an insufficient interference fit.

Accident Description

A helicopter experienced an in-flight break-up while traveling at approximately 130 knots at an altitude of 960 feet above the ground. The wreckage path was oriented on a 090 heading, located between 0.8 and 1.2 miles west of the Spencer, Iowa, airport.

Examination Findings

Post-accident examination focused on the swashplate outer ring pins. Investigators identified a bending fatigue fracture in the component referred to as the 'white' pin. The fatigue cracking originated in the undercut fillet radius adjacent to the head of the pin. The 'white' and 'red' bores, as well as the 'red' pin (the 'white' pin was not located), were checked for proper dimensions. The examination indicated an insufficient interference fit between the outer swashplate bores and the outer diameter of the swashplate ring pins.

Probable cause

Fatigue fracture of the white swashplate outer ring pin due to an insufficient interference fit between the outer swashplate bores and the outer diameter of the swashplate ring pins.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X10786. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.