What happened
On 20 December 2005, a Beech Queen-Air 70, registration N70AA, was conducting a cargo flight from Coventry, UK, to Ireland West Airport, Knock. Due to unfavorable weather conditions at the intended destination, the pilot diverted to Sligo Airport. The weather at Sligo was favorable, with the aircraft utilizing runway 11.
During the landing roll, the aircraft began to veer sharply to the left. In an effort to avoid striking the runway edge lights and causing further damage, the pilot steered the aircraft off the paved surface and onto the grass area north of the runway. Following this excursion, the pilot managed to steer the aircraft back onto the runway and taxied slowly toward the apron. Upon engine shutdown, an inspection revealed significant damage to the left main undercarriage.
The investigation
Investigators examined the aircraft's left-hand main torque link to determine the cause of the sudden veer. The metallurgical analysis revealed that the torque link had failed at two attachment points to the landing gear leg, while the remaining attachment points were cracked. Additionally, the joint within the link had failed.
Scanning Electron Microscope (SEM) examination of the fracture surfaces showed bright features characteristic of a single event overload. The investigation found no evidence of pre-existing cracks, fatigue, or inherent defects in the component prior to the landing.
Findings
- The failure of the torque link was caused by a single-event overload.
- There were no pre-existing defects or inherent flaws in the torque link.
- Weather conditions were not a contributing factor to the incident.