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Continental Airlines Flight 1933

12 Sept 1999 · West Palm Beach, FL, United States

Boeing B737-300 · Accident: partial loss of engine power (mechanical failure) en route

From PBI to George Bush Intercontinental Airport (IAH)

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Event

NTSB case
MIA99FA252
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
Accident
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 B737-300

Aircraft type
Boeing 737
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
N17356
Onboard fatalities
Unknown
Route
From PBITo George Bush Intercontinental Airport (IAH), Houston, TX
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 121: Air Carrier
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
En route · climb to cruise
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
Partial 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
Substantial

Cause areas

  • Manufacturer › Insufficient standards/requirements, manufacturer
  • Turbine assembly, air seal › Fatigue
  • Turbine assembly, air seal › Separation

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

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.

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 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.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record MIA99FA252
Event ID
20001212X19822
Case number
MIA99FA252
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: investigation status. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: e7d66483e37517092e7cb53a9496888628f7542d20b1e70bf9f099f88bf4e313; retrieved 2026-09-18T16:53:13.090Z.