British BAE 146 N608AW

Summary

On 27 May 1996 at about 02:20 local time, a British BAE 146 registered N608AW, operated by Air Wisconsin, was involved in an incident near Des Moines, Iowa, United States. 58 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

27 May 1996 at 02:20

Classification

Incident

Location

Des Moines, Iowa, United States

Nearest airport

Des Moines (DSM)

Coordinates

Not recorded

Aircraft

British BAE 146

Registration

N608AW

Category

Airplane

Engines

4

Operator

Air Wisconsin

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Denver → Moline

Aircraft damage

Not recorded

Weather

IMC

Light

Night/Dark

NTSB number

CHI96IA173

Nobody was injured.

failure of the flight crew to follow proper procedures, which resulted in an accumulation of ice and subsequent loss of engine power. Factors relating to the incident were: thunderstorms, turbulence, icing conditions, and the inaccurate method that was provided by the manufacturer for determining 'in cloud' air temperature and icing conditions.

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

Read the full NTSB narrative

While operating in clouds at flight level 290, in an area with thunderstorms and turbulence, the airplane experienced a loss of power in all four engines. Information from the flight data recorder indicated that during descent from flight level 290, an elevator oscillation occurred. The #1 and #2 engines were shut down due to high turbine gas temperatures. The #2 engine was restarted before making an emergency landing at the Des Moines Airport. The captain reported that the airplane had been flown into severe icing conditions. The aircraft flight manual (AFM) prohibited flight in icing conditions above 26,000 feet (except when necessary for descent). Also, the AFM stipulated the minimum engine speeds which needed to be maintained while operating in icing conditions; it also required that the thrust management system (TMS) be disconnected in icing conditions. There were indications that the TMS was disconnected about 230 seconds after engine roll-back began. Additionally, the AFM did not provide accurate information concerning 'in cloud' correction factor for the outside temperature thermometer.

Quoted verbatim from the NTSB record.