What happened
The captain was conducting a visual approach following the localizer to intercept the glideslope when the crew selected flaps 45. Upon this configuration change, the aircraft experienced a right roll of approximately 15 to 20 degrees. The crew managed the roll using left aileron and rudder inputs and subsequently aborted the approach.
Following a consultation with flight operations and maintenance, along with a visual inspection, the captain identified a failure in the right flight spoiler. The crew elected to land using corrected speeds as prescribed by the aircraft checklist. The subsequent approach and landing were completed without further incident.
The investigation
A post-flight inspection determined that the right flight spoiler was fully deployed. Investigators found that the right spoiler lug had fractured and separated from its hydraulic actuator.
Review of maintenance records showed the right flight spoiler had accumulated 4,064 landings and a total of 3,987.9 cycles. A metallurgical examination of the component determined that the aluminum spoiler lug failed due to fatigue.
Findings
- The failure was caused by fatigue in the aluminum spoiler lug.
- Transport Canada had previously issued an Airworthiness Directive on February 22, 2001, requiring inspections of aluminum flight spoiler lugs at 3,000 cycles and every 500 cycles thereafter.
- The directive noted that installing redesigned spoilers with steel lugs would terminate the inspection requirement.
- The FAA issued a matching Airworthiness Directive on July 26, 2001.