Printed headline: Lapping Reminder
India’s Aircraft Accident Investigation Bureau recently released a final investigative report on an uncontained engine failure and inflight shutdown involving an Air India Airbus A320 that occurred in August 2014.
The probable cause of the incident was improper lapping processes that resulted in seal-plate blockage and subsequent oil seepage.
The subject International Aero Engines V2500 turbofan engine had logged 8,163 hr. since its last overhaul. Investigators determined that during the overhaul. Investigators determined that during the overhaul, seal-plate weep grooves and holes had been blocked with lapping debris. Without a means to escape, oil migrated into the high-pressure turbine and ultimately ignited.
The report was issued more than two years after a manufacturer’s service bulletin and subsequent airworthiness directive. The FAA mandate required removal and replacement of front and rear seal seats. The final safety recommendation reminds operators of that requirement.