Incident Overview

Date: Sunday 10 September 2000
Aircraft Type: Boeing 727-224
Owner/operator: Sun Country Airlines
Registration Number: N296SC
Location: MINNEAPOLIS, MN – ÿ United States of America
Phase of Flight: Taxi
Status: Substantial
Casualties: Fatalities: 0 / Occupants: 101
Component Affected: Wheel assemblyWheel assembly
Investigating Agency: NTSBNTSB
Category: Accident
A Boeing 727-224 aircraft experienced a failure during taxi for takeoff, resulting in damage to wheel assembly. A fatigue failure originating from a point within a brake lug induced a circumferential scratch and ultimately led to a complete wheel assembly failure. The aircraft had accumulated 356.2 hours of service, and prior inspection records indicated a high rate of repair rejection by the repair station.A Boeing 727-224 aircraft experienced a failure during taxi for takeoff, resulting in damage to wheel assembly. A fatigue failure originating from a point within a brake lug induced a circumferential scratch and ultimately led to a complete wheel assembly failure. The aircraft had accumulated 356.2 hours of service, and prior inspection records indicated a high rate of repair rejection by the repair station.

Description

The Boeing 727-224 number 3 wheel assembly failed during taxi for takeoff and pieces of the wheel assembly impacted the airframe causing damage. Examination of the wheel assembly revealed a fatigue failure that emanated from a point at the inside diameter of one of the brake lugs. A circumferential scratch was found adjacent to the fatigue origin. The wheel half had been inspected by an approved repair station and shipped to the airline on July 21, 2000. The wheel was installed on the accident aircraft and had accumulated 356.2 hours time in service at the time of the accident. A review of repair station records revealed that the repair station had been rejecting about 4 wheel halves per month. Prior to the accident, the repair station was finding cracks on other wheel halves in the area where the wheel failure occurred. The repair station had been in contact with the wheel manufacturer concerning this matter and had sent representative wheel halves to the manufacturer for evaluation. In a conversation with a representative of the Federal Aviation Administration, the wheel manufacturer stated that one of the returned wheel halves had been examined and that a manufacturing defect had created a stress concentrator, which resulted in a fatigue failure of the wheel half. The wheel manufacturer issued a Service Bulletin to rework the lugs and to provide guidance in inspecting the affected areas of the wheel assembly. Probable Cause: The fatigue failure of the wheel assembly. A factor was the inadequate inspection procedures prior to the issuance of a service bulletin.

Primary Cause

Fatigue failure of the wheel assembly due to an inadequate inspection procedure prior to a Service Bulletin.Fatigue failure of the wheel assembly due to an inadequate inspection procedure prior to a Service Bulletin.

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