Trans States Airlines Embraer EMB-145LR incident
Embraer EMB-145LR · Incident: total loss of engine power (mechanical failure) en route
From St. Louis Lambert International Airport (STL) to Denver International Airport (DEN)
Event
- NTSB case
- CHI05IA116
- 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
- Unknown
- 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
Embraer EMB-145LR
- Aircraft type
- Embraer EMB-145
- 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
- N814HK
- Operator
- Trans States Airlines
- Onboard fatalities
- Unknown
- Route
- From St. Louis Lambert International Airport (STL), ST LOUIS, MOTo Denver International Airport (DEN), Denver, CO
- 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 · 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
- 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
- Compressor assembly, blade retention › Failure
- Compressor assembly, blade retention › Fatigue
- Manufacturer › Acft/equip, inadequate design
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane sustained minor damage as a result of an uncontained failure of the left engine. Examination of the airplane revealed that the left engine's fan spinner was completely missing, and the forward fan blade retainer was missing a 90-degree section of the bolt flange. Several pieces of the fan spinner were recovered within the cowl. The NTSB's examination of the fan blade forward retaining ring revealed features indicative of overstress failure which originated on the forward face adjacent to a linear impression. The length and location of the linear impression corresponded to the corner on one of the bolt lugs on the aft side of the spinner. The linear impression contained evidence of fretting damage. The inside radius between the retaining ring's raised lip, and the flange was within the range specified by the manufacturer. The spinner's bolt lugs had a sharp outside corner where the spinner would interface with the radius on the retaining ring. The forging drawing for this part did not specify a radius; however, a manufacturer's representative indicated that an engineering drawing for the spinner specified that exterior corners have an edge break with a radius between 0.005 and 0.020 inches. The combination of the radius on the retaining ring, and the sharp edge on the aft side of the spinner, resulted in an interference when the parts were assembled. The manufacturer's examination of the retained parts indicated the presence of high cycle fatigue on both the spinner and the fan blade retaining ring. Three dimensional finite element analysis of the fan spinner, and forward fan blade retaining ring predicted a reduced low cycle fatigue life. As a result of this investigation, the manufacturer initiated a one-time, on-wing eddy current inspection of all the one-piece fan spinners to be accomplished within 18 months or 2,000 hours. The manufacturer also initiated a re-design of the fan spinner, and indicated that the one-piece fan spinners will be removed from service by the end of 2010.
Probable cause
The fatigue failure during cruise flight of the fan spinner and forward fan retaining ring due to an interference between the mating parts resulting from the inadequate design by the manufacturer.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI05IA116
- Event ID
- 20050520X00650
- Case number
- CHI05IA116
- 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: c0c78d2a3baab41233f3589a92f0d1f51369b89d0cb33b37974bed1b39699cb2; retrieved 2026-09-18T15:02:26.811Z.