Saab-Scania Ab (Saab) 340B N313AE

Summary

On 13 May 1997 at about 13:05 local time, a Saab-Scania Ab (Saab) 340B registered N313AE, operated by Wings West Airlines, Inc, was involved in an incident near San Luis Obispo, California, United States. 21 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

13 May 1997 at 13:05

Classification

Incident

Location

San Luis Obispo, California, United States

Nearest airport

San Luis Obispo County (SBP)

Coordinates

35.2498, -120.6201

Aircraft

Saab-Scania Ab (Saab) 340B

Registration

N313AE

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 → Los Angeles

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

LAX97IA180

Nobody was injured.

Compressor stalls of both engines due to in-service compressor contamination. Factors in the compressor stall of the right engine were an atmospheric temperature inversion and a transient fuel flow condition produced when the constant thrust on takeoff (CTOT) system was disabled by the pilot's inadvertent movement of the right engine power lever during execution of the emergency procedure.

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

Read the full NTSB narrative

The flight crew reported that all pretakeoff checks were normal and that prior to setting takeoff power the Constant Thrust on Takeoff (CTOT) computer was set to 100-percent engine torque for takeoff. The ensuing takeoff was normal through liftoff and gear retraction; however, during initial climb the left engine experienced compressor stalling and lost power. As the crewmembers were executing the engine failure checklist, the right engine first increased power in Automatic Power Reserve (APR) and then began to similarly stall and lose power. After about 20 seconds the engines recovered sufficient power to enable the flight crew to remain airborne and return for landing on the departure runway. Review of the digital flight data recorder (DFDR) output and internal examination of each engine revealed that the engines had compressor stalled due to accumulated dirt and contaminants on the compressors. A review of the right engine DFDR data revealed that, while the left engine was stalling, the flight crew had retarded the right engine power lever past the 64-degree power lever angle position which tripped off the CTOT system. The resulting transient in fuel flow, in company with an atmospheric temperature inversion, reduced the stall margin of the right engine.

Quoted verbatim from the NTSB record.