Pakistan International Airline Flight 722
Boeing 747-240 · Incident: total loss of engine power (mechanical failure) during initial climb
From John F. Kennedy International Airport (JFK) to PARIS,FRANCE
Event
- NTSB case
- NYC96IA036
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Incident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Boeing 747-240
- Aircraft type
- Boeing 747
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- APBAK
- Operator
- Pakistan International Airline
- Onboard fatalities
- Unknown
- Route
- From John F. Kennedy International Airport (JFK)To PARIS,FRANCE
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 129: Foreign
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Initial climb
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Company maintenance personnel › Maintenance, inspection, inadequate
- Turbine assembly, shaft › Fatigue
Approximate · Estimated position: the centre of Jamaica, NY, the place the record names. Not the accident site.
NTSB narrative
After takeoff, about 1,000 ft agl, the crew of the Boeing 747-240 heard a 'thudding noise,' followed by a loss of power in the number two engine. An engine shut down was completed, and an uneventful landing was made at the departure airport. The airplane was equipped with General Electric CF6-50E2 engines. Examination revealed that the low pressure turbine module, which included a portion of the fan mid shaft (FMS) and turbine rear frame, was missing. The airplane sustained damage to the left wing leading and tailing edge flaps, the left main wing landing gear doors, and the number one engine. Examination of the number two engine revealed a fracture face on the forward end of the FMS that showed multiple fatigue origins and circumferential cracks. There were also areas on the FMS that were heat affected. The FMS had previously been installed in a CF6-50 engine that had sustained a failure of the number 3 bearing inner race. The engine had been inspected by company personnel, and records did not reflect that they inspected the FMS for heat affected material. Fatigue cracks located in the heat-affected areas were found to have Sermetel paint and debris in the cracks.
Probable cause
failure of the number two engine fan mid shaft, due a fatigue fracture caused by a previous bearing failure, and failure of the operator's maintenance personnel to detect the cracks during subsequent inspections.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record NYC96IA036
- Event ID
- 20001207X05066
- Case number
- NYC96IA036
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1995-12-07.
- API snapshot SHA-256: ed373726e0e08f1a26d226acc0e82ecf9c067da9fd61faec29ab92d293bb8d43; retrieved 2026-09-18T17:56:00.196Z.