Boeing B737-300 accident near West Palm Beach, Florida, September 12, 1999
On September 12, 1999 at about 11:11 am local time, a Boeing B737-300, registered N17356, was substantially damaged in an accident near West Palm Beach, Florida. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 89 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
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 inadequate and ineffective inspection techniques. Contributing to the accident was the engine manufacturers failure to provide adequate hole making requirements at the time the forward rotating air seal was manufactured and the engine manufacturers failure at the time of last inspection to require eddy current inspections for the high pressure turbine forward rotating air seal bolt holes.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 12, 1999 · about 11:11 am local time
- Place
- West Palm Beach, Florida · map
- Type
- Accident
- Injuries
- No one was hurt; 89 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing B737-300
- Registration
- N17356 · registry record · serial 23942
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
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 complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 10,500 hours in all; 6,500 in this make and model; 149 in the last 90 days; 58 in the last 30 days; 10,100 as pilot in command; 6,400 on instruments
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 34,602 hours
- Last inspection: continuous airworthiness programme, August 18, 1999; 222 hours since
- Maximum gross weight: 135,000 lb
- Seats: 134
- Landing gear: retractable
- Engine: Cfm CFM56-3B1 (turbofan); 0 hours total
- Operator: Continental Airlines
The flight
- Departed from: PBI at 11:11 am
- Destination: IAH Houston TX
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 030° at 3 knots
- Visibility: 10 statute miles
- Sky: scat at 20,000 ft
- Temperature: 81°F (27°C), dew point 73°F (23°C)
- Altimeter: 29.00 inHg
- Observation at 10:53 am from PBI, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 84 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number MIA99FA252.