# Accident 19990912041969A: Boeing 7373T0, West Palm Beach, FL, September 12, 1999

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: September 12, 1999, 07:11 local time
- Place: West Palm Beach, FL
- Airport: Palm Beach International
- Damage: Substantial damage
- Phase of flight: Climb
- Operating rules: Air carrier (Part 121)
- Operator: CALA
- Location: 26.6604° N, 80.0904° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=26.6604&lon=-80.0904&mi=10
- Aircraft: N17356, a cancelled registration (https://openairdocs.org/deregistered/N17356-2013-03-21) (OpenAirDocs)
- Registry model: Boeing 737-3TO (registry code 138447G, https://openairdocs.org/model/boeing-737-3to) (OpenAirDocs)
- Registry engine: GE CFM56 series (registry code 30016, https://openairdocs.org/engine/ge-cfm56-series) (OpenAirDocs)
- Reported make and model: BOEING 7373T0
- Reported engine: GE CFM563B1
- People aboard: 89
- Fatal injuries: 0
- Pilot flight hours: 10,500 total, 6,500 in this make and model, 149 in the last 90 days
- NTSB investigation: [NTSB MIA99FA252](https://openairdocs.org/ntsb/MIA99FA252) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19990912041969A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

(-23) #1 ENGINE SUSTAINED AN UN-CONTAINED FAILURE DUE TO 7TH STAGE TURBINE DISK AIR SEAL (HIGH PRESSURE) THAT IS ATTACHED TO 7TH STAGE DISK. SHAFT SHEARED AND DISPERSED ENGINE FRAGMENTS 8X3 OVER CITY BLOCK, NTSB HAD ENGINE REMOVED AND SENT TO HOUSTON FOR FURTHER INVESTIGATION. (.4)DURING CLIMB AFTER TAKEOFF, THE FLIGHT HAD AN UNCONTAINED FAILURE OF THE NO. 1 ENGINE. THE FLIGHT RETURNED TO THE DEPARTURE AIRPORT AND LANDED WITHOUT FURTHER INCIDENT. EXAMINATION OF THE AIRPLANE SHOWED THERE WAS DAMAGE TO THE LEFT WING HIGH LIFT DEVICES, FUSELAGE, VERTICAL AND HORIZONTAL STABILIZERS, RUDDER, AND TAIL CONE. THE NO. 1 ENGINE LEFT THRUST REVERSER HAD SEPARATED. DEBRIS FROM THE NO.1 ENGINE WAS LOCATED OVER AN EIGHT BLOCK LONG BY THREE BLOCK WIDE CITY BLOCK AREA. EXAMINATION OF THE NO. 1 ENGINE REVEALED THAT IT HAD A 360 DEGREE SEPARATION IN PLANE WITH THE HIGH PRESSURE TURBINE (HPT) ROTOR AND THAT THE HPT SHAFT AND THE HPT FORWARD ROTATING AIR SEAL HAD EXITED THE ENGINE. THE HPT ROTATING AIR SEAL WAS RECOVERED IN THE DEBRIS FIELD. METALLURGICAL EXAMINATION SHOWED THE ROTATING AIR SEAL HAD TWO RADIAL FRACTURES THAT PASSED THROUGH THE BORE AND THE HPT FRONT SHAFT-TO-HPT                       DISK ATTACHMENT BOLT HOLES. FATIGUE CRACKING WAS IDENTIFIED IN ONE ATTACHMENT BOLT HOLE WHICH INITIATED FROM A HEAT AFFECTED LAYER. THE HEAT AFFECTED LAYER WAS CAUSED BY ABUSIVE MACHINING DURING THE MANUFACTURING PROCESS DUE TO LOSS OF COOLANT DURING THE DRILLING PROCESS. BASED ON STRIATION COUNT, THE FATIGUE CRACK WAS AT DETECTABLE LENGTH DURING TWO IN-SERVICE INSPECTIONS, BUT WAS NOT DETECTED.

## The NTSB's investigation of this event (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB MIA99FA252](https://openairdocs.org/ntsb/MIA99FA252), Sep 12, 1999: Boeing B737-300 (N17356), West Palm Beach, FL, substantial damage. Probable cause: The fatigue fracture and separation of the high pressure turbine forward rotating air seal due to a manufacturing defect in a bolt hole that was not detected by the engine manufacturer due to…

## Other reports on N17356 (1)

Matched to the same aircraft by N-number and date.

- [Incident 19940711032989I](https://openairdocs.org/incident/19940711032989I), Jul 11, 1994: Boeing 737300 (N17356), Kansas City, MO. Altitude deviation. Crew got it wrong but ATC failed to get positive read back.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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