Created Saturday, Dec 2nd 2023 12:29Z, last updated Wednesday, Jan 21st 2026 18:37Z
A PIA Pakistan International Airlines Boeing 777-200, registration AP-BMH performing flight
PK-743 from Karachi (Pakistan) to Madinah (Saudi Arabia) with 276 people on board, was climbing out of Karachi's runway 07R when the right hand engine (GE90) emitted a loud bang, sparks and streak of flames, a fire warning for the engine occurred. The crew stopped the climb at 3000 feet, shut the engine down, discharged at least one fire bottle and returned to Karachi for a safe landing on runway 25L about 15 minutes after departure.
Pakistan's DGCA opened an investigation into the occurrence.
The airline reported the crew received an engine fire warning prompting the emergency response. A post flight inspection revealed no evidence of a fire however. A replacement flight to Madinah is being prepared.
In Jan 2026 Pakistan's BASIP released their final report concluding the probable cause of the serious incident was:
The incident was caused by a right engine overheat warning during flight caused by a significant bleed air leak from the 14th stage of the HPC which resulted due to a disconnection of a high-pressure (HP) pneumatic duct on the right engine due to improper installation of its duct clamp.
Contributing factors were:
- Improper Installation and Torque Omission – The clamp securing the HP pneumatic duct was likely loosened during component removal or installation but not re-torqued or verified thereafter. The absence of mechanical deformation on the clamp supports a conclusion of human error during re-installation.
- Non-compliance with Maintenance Procedures – No leak checks were performed post-engine installation on the right engine, contrary to Aircraft Maintenance Manual (AMM) requirements.
- Human Factors and Work Environment Limitations – Critical maintenance tasks were performed under night-shift conditions with suboptimal tools (ladders instead of platforms), limited accessibility, and poor visibility, increasing the risk of oversight and fatigue-induced errors.
- Ineffective Communication and Task Handover – Technicians did not
report unusual installation difficulties (e.g., multiple HPSOV fitting attempts, unorthodox E-seal alignment), preventing escalation or cross-checks during successive shift turnovers.
- Organizational Culture and Documentation Gaps – A task-oriented maintenance culture, influenced by logistical pressure and reliance on cannibalized parts is evident. Further, lack of communication between maintenance teams of the components disturbed during the completion of task at hand led to missing of verification processes for those components that required re-inspection.
The BASIP analysed that no evidence of an actual engine fire was found and stated:
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Further inspection of engine revealed a disconnected HP pneumatic duct at 3 o’clock position of the right engine, near the High-Pressure Compressor (HPC) case. The associated duct clamp, which secures the Y-shaped pneumatic duct in the HP bleed air system, was found in the lower engine area near 6 o’clock position.
The right engine’s thrust reverser Pressure Relief 02 doors were also found in operated position indicating hot air leak in the area. Secondary damage to the righthand thrust reverser cowling also indicate a pneumatic leak in the area.
The collected evidences point towards a right engine overheat warning during flight caused by a significant bleed air leak from the 14th stage of the HPC.
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Related Flight:
PK743,
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