Embraer EMB-145LR N814HK

Summary

On 19 May 2005 at about 14:25 local time, a Embraer EMB-145LR registered N814HK, operated by Trans States Airlines Inc, was involved in an incident near Kansas City, Missouri, United States. 54 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 May 2005 at 14:25

Classification

Incident

Location

Kansas City, Missouri, United States

Coordinates

39.2690, -94.7306

Aircraft

Embraer EMB-145LR

Registration

N814HK

Category

Airplane

Engines

2

Operator

Trans States Airlines Inc

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

St Louis → Denver

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

CHI05IA116

Nobody was injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.