Saab-Scania Ab (Saab) S340B N245AE

Summary

On 3 May 1994 at about 11:03 local time, a Saab-Scania Ab (Saab) S340B registered N245AE, operated by Wings West Airlines, Inc., was involved in an incident near Nashville, Tennessee, United States. 16 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

3 May 1994 at 11:03

Classification

Incident

Location

Nashville, Tennessee, United States

Coordinates

36.1097, -86.6596

Aircraft

Saab-Scania Ab (Saab) S340B

Registration

N245AE

Category

Airplane

Engines

2

Operator

Wings West Airlines, Inc.

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Baton Rouge → Unknown

Aircraft damage

Not recorded

Weather

IMC

Light

Day

NTSB number

ATL94IA092

Nobody was injured.

ENGINE ICE/SLUSH INGESTION THAT RESULTED IN POWER INTERRUPTIONS AND FAILURE OF THE AIR DATA COMPUTER COUPLED WITH MOISTURE INGESTION OF THE STATIC SYSTEM. FACTORS WERE THE FAILURE OF THE MANUFACTURER TO CORRECT A PREVIOUSLY IDENTIFIED DESIGN DEFICIENCY THAT PERMITTED THE ACCUMULATION OF ENGINE INLET ICE/SLUSH, WHICH COULD NOT BE OBSERVED BY THE FLIGHT CREW, NOR PREVENTED BY ON-BOARD ENGINE ANTI-ICE EQUIPMENT, THE LACK OF A PROACTIVE STANCE BY THE FAA WHEN INVOLVED WITH AIRCRAFT CERTIFICATION UNDER BI-LATERAL AGREEMENTS, AND THE INADEQUACY OF THE FEDERAL AVIATION REGULATIONS REGARDING ENGINE INLET ICE PROTECTION.

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

Read the full NTSB narrative

THE ACFT WAS PARKED ON THE RAMP OVER NIGHT, UNCOVERED, IN CONTINOUS RAIN. TAKEOFF WAS MADE IN HARD RAIN. AFTER REACHING CRUISE FLIGHT (FL250), ENGINE POWER INTERRUPTIONS OCCURRED IN BOTH ENGINES. FLIGHT CONDITIONS WERE IMC, -20 DEG. OAT, AND LIGHT RIME ICING. ALSO, ALL AIRSPEED INDICATIONS DECREASED TO ZERO. A DESCENT WAS BEGUN, AND THE FLIGHT CREW DECLARED AN EMERGENCY. THE AIRPLANE WAS LANDED SAFELY AT ITS DESTINATION. THE INVESTIGATION DISCOVERED THAT ENGINE POWER INTERRUPTIONS HAVE OCCURRED IN LIGHT ICING CONDITIONS SINCE THE INTRODUCTION INTO REVENUE SERVICE OF THE ACFT. AD'S WERE ISSUED TO PROHIBIT REVENUE FLTS, THEN FLTS IN ICING CONDITIONS WITHOUT AN AUTO IGNITION. THE MANUFACTURER HAD DETERMINED THAT ICE/SLUSH COULD BUILD UP ON THE INLET PARTICLE SEPARATOR, BREAK OFF, AND ENTER THE ENGINE, RESULTING IN FLAMEOUT. THE ICE/SLUSH COULD NOT BE SEEN BY THE PILOTS, AND WAS NOT REDUCED BY ENGINE ANTI-ICE. AN AUTO IGNITION WAS ADDED THAT RESTARTED THE ENGINE WITHIN 2 SECONDS. ACFT CERTIFICATION RULES REQIRE THAT NO ACCUMULATION OF ENGINE INLET ICE OCCUR THAT WILL ADVERSELY AFFECT THE ENGINE OPERATION.

Quoted verbatim from the NTSB record.