Airbus A319 132 N516NK incident near Greenville, Texas

Probable cause

A high pressure turbine 2nd stage blade separation due to stress corrosion cracking in the J channel cooling cavity. The failed blade entered the gas path and caused substantial damage to the low pressure turbine. The engine was subsequently left at a high power setting for approximately four minutes, exposing the turbine hardware to temperatures that exceeded the material annealing temperature and resulted in in failure and separation of multiple engine components.

NTSB analysis

Based on metallurgical analysis, a No. 1 engine high pressure turbine (HPT) 2nd stage blade separated below the blade platform due to stress corrosion cracking in the blade J-channel cooling air cavity. The liberated blade entered the gas path and caused extensive damage to the HPT and low pressure turbine (LPT) hardware and cases. The damaged engine was left at a high power setting for about four minutes until the crew received a No. 1 engine fire warning. During this time the turbine was exposed to temperatures that exceeded the material annealing temperature and resulted in failure and separation of multiple components including the LPT 3rd and 4th stage disks, turbine exhaust case center body, and the No. 5 bearing housing. The engine nacelle was not breached and all separated engine components traveled out the back of the engine.

Text from the NTSB. Open the NTSB docket for ENG14IA001 for the full record.