What happened
On 23rd December 2019, an Airbus A320(NEO), registration VT-WGL, operated by Go Airlines (India) Limited, was performing a scheduled flight from Guwahati to Kolkata. Shortly after takeoff, while the aircraft was climbing through 1,500 feet, the flight crew heard a loud bang. This was immediately followed by "Engine Stall" and "High Engine Vibration" warnings on the Engine-Indicating and Crew-Alerting System (ECAM) for the number one engine.
As the crew managed the situation, vibration levels for both N1 and N2 reached 10 units, and Exhaust Gas Temperature (EGT) rose significantly. During the climb, cabin crew and passengers observed a fire in the engine tailpipe. Following standard operating procedures, the crew reduced power on the affected engine to idle and eventually performed a precautionary shutdown. The aircraft returned to Guwahati and landed safely without any injuries to the 133 passengers or the crew.
The investigation
AAIB India investigators examined the engine and found that all 7 and 8 blades of the 3rd stage Low-Pressure Turbine (LPT) had fractured. Laboratory analysis conducted by NAL, Bengaluru, revealed that the blades had failed in a brittle manner. The study confirmed that the material used—a Gamma Titanium Aluminide (Ti-Al) intermetallic—lacked sufficient crack growth resistance and damage tolerance.
Testing showed that once a crack initiated, it propagated almost instantaneously. The investigation also noted that the engine was equipped with pre-modification blades that were highly sensitive to impact damage from any upstream debris.