Learjet N244F

Summary

On 12 August 2007 at about 19:30 local time, a Learjet registered N244F, operated by D&D Aviation, was involved in an incident near Salt Lake City, Utah, United States. 2 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

12 August 2007 at 19:30

Classification

Incident

Location

Salt Lake City, Utah, United States

Nearest airport

Salt Lake City International (KSLC)

Coordinates

40.7507, -111.9007

Aircraft

Learjet

Registration

N244F

Category

Airplane

Engines

2

Operator

D&D Aviation

Operating rule

Part 91: General Aviation

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Salt Lake City → Wichita

Aircraft damage

Not recorded

NTSB number

ENG07IA034

Nobody was injured.

The fatigue fracture of the fan blade due to the blade vendor's improper setup of the forging dies, which resulted in fan blades with airfoils that were below the minimum thickness in the highest stressed area of the airfoil and resulted in operating stresses that exceeded the material's capability. Contributing to the incident was the engine manufacturer's lack of a dimensional inspection of the fan blade's airfoil.

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

Read the full NTSB narrative

The airplane experienced an in-flight fan blade separation in the left engine, a Pratt & Whitney Canada (PWC) PW305A turbofan, while the airplane was climbing through FL 380 shortly after takeoff from Salt Lake City (SLC), Utah. The airplane returned to SLC for an overweight, single-engine landing without further incident. Examination of the engine revealed that two fan blades were fractured transversely across the airfoil adjacent to the blade root platform. Metallurgical examination of the fan blades determined that one fan blade had separated from a fatigue fracture and the other separated from overload, although the fracture had coincided with a preexisting fatigue crack. A fluorescent penetrant examination of the left engine's remaining fan blades revealed that several blades had crack indications. A dimensional inspection of the cracked fan blades revealed that they were under the minimum thickness in a highly stressed area of the airfoil. The investigation determined that the fan blades were too thin due to an improper forging die setup when the blades were manufactured. At the time the fan blades were made, PWC did not require a dimensional inspection of the fan blade airfoils.

Quoted verbatim from the NTSB record.