Saab-Scania Ab (Saab) SF340B N335AE

Summary

On 1 July 1996 at about 12:11 local time, a Saab-Scania Ab (Saab) SF340B registered N335AE, operated by Wings West Airlines, Inc., was involved in an accident near Dfw Airport, Texas, United States. 15 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

1 July 1996 at 12:11

Classification

Accident

Location

Dfw Airport, Texas, United States

Nearest airport

Dfw International Airport (DFW)

Coordinates

Not recorded

Aircraft

Saab-Scania Ab (Saab) SF340B

Registration

N335AE

Category

Airplane

Engines

2

Operator

Wings West Airlines, Inc.

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Unknown → Shreveport

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

FTW96FA282

Nobody was injured.

The manufacturer's inadequate procedure for manufacturing the number two turbine disk.

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

Read the full NTSB narrative

The airplane departed runway 13L and climbed to an altitude of approximately 400 feet AGL when the flight crew 'heard a loud bang.' The right engine upper cowling departed the airplane, the right engine shut itself down, and the right propeller automatically feathered. The flight crew declared an emergency and executed a single engine landing without further incident. Examination of the airplane's right CT7-9B turboprop engine revealed that the Stage 2 turbine disk was missing and that approximately one third of the disk was found in the right landing light compartment. One end of the disk fragment progressed through a cooling air hole and there was evidence of a fatigue fracture that had initiated from multiple origins on the inboard side of the cooling air hole. Research revealed a layer of deformed microstructure and an associated zone of increased disk hardness near the origin area of the fatigue crack. Test disks were drilled using dull and worn drill bits which resulted in plastic deformation and increased hardness of the inner diameter hole surfaces. The manufacturer reported that the deformed microstructure correlates to a zone of reduced fatigue properties.

Quoted verbatim from the NTSB record.