What happened
On 18 December 2021, a Boeing 737-200, registration PK-JRW, was performing a scheduled cargo flight from Sentani International Airport to Wamena Airport, Papua. The aircraft was carrying 12,556 kg of cargo and was operated within its proper weight and balance limits.
As the aircraft reached rotation speed on runway 30, the crew heard a loud bang accompanied by intense vibrations throughout the airframe. Airport CCTV footage captured a fire blast exiting the right engine exhaust during this rotation phase. The pilot monitoring immediately notified Air Traffic Control of the emergency. Following the procedure for engine severe damage, the crew climbed to 4,500 feet to hold and perform necessary checklists before returning to Sentani. The aircraft landed safely at 0903 LT, but a subsequent inspection by an engineer revealed extensive damage to the right engine.
The investigation
The KNKT investigation focused on the mechanical state of the right engine and the distribution of debris. Investigators located engine fan blade fragments on the runway and within a residential area near the threshold of runway 12. A borescope inspection of the right engine revealed that compressor blades from stage 1 through stage 5 were severely damaged, while blades from stage 7 through stage 13 were bent, dented, or torn. The combustion chamber and turbines remained undamaged.
Findings
- The right engine was nearing a scheduled shop visit, with only 1,226 cycles remaining before the limit life of the HP Compressor stage 8 was reached.
- The operator lacked an active engine monitoring program, which could have identified performance degradation before the failure.
- The aircraft was operating within all regulatory weight and balance envelopes, and the crew held valid licenses and medical certificates.