Individually Owned: 150,657
Corporate Owned: 137,281
Des Moines Airport
Aircraft Accident/Incident Report
Des Moines, Iowa 50318
Sunday, May 26, 1996 21:20 CDT
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
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.
Event Information
| Type of Event | Incident |
| Event Date | 5/26/1996 |
| Event Day of the Week | Sunday |
| Time of Event | 2120 |
| Event Time Zone | Central Daylight Time |
| Event City | DES MOINES |
| Event State | IOWA |
| Event Country | -- |
| Zipcode of the event site | 50318 |
| Event Date Year | 1996 |
| Event Date Month | 5 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | DES MOINES |
| Event Location Nearest Airport ID | DSM |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 60 |
| Degrees magnetic from airport | 245 |
| Airport Elevation | 957 |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 2156 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | 220 |
| Weather Observation Facility ID | DSM |
| Elevation of weather observation facility | 957 |
| Distance of event from weather observation facility (units?) | 50 |
| Time Zone of the weather observation | CDT |
| Lighting Conditions | Night/Dark |
| Lowest Ceiling Height | 1200 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Unknown |
| Sky Condition for Lowest Ceiling | Overcast |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 3.5 |
| Air Temperature at event time (in degrees celsius) | 11 |
| Dew Point at event time (in degress fahrenheit) | 10 |
| Wind Direction (degrees magnetic) | 80 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 13 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 19 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 58 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 5022 |
| NTSB Notification Source | -- |
| NTSB Notification Date | May 26 1996 12:00AM |
| NTSB Notification Time | 2230 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Dec 8 2000 9:59AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Instrument Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N608AW |
| NTSB Number | CHI96IA173 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | -- |
| Damage | None |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | British Aerospace |
| Aircraft Model | BAE 146 |
| Aircraft Series Identifier | BAE 146 |
| Aircraft Serial Number | E2049 |
| Certified Max Gross Weight | 89500 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 100 |
| Number of Engines | 4 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | May 26 1996 12:00AM |
| Airframe hours since last inspection | 10 |
| Airframe Hours | 18978 |
| ELT Installed | No |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | NORTHERN LEASING COMPANY INC |
| Aircraft Owner Street Address | |
| Aircraft Owner City | |
| Aircraft Owner State | |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | |
| Operator is an individual? | -- |
| Operator Name | AIR WISCONSIN |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | W 6390 CHALLENGER DRIVE # 203 |
| Operator City | APPLETOWN |
| Operator State | WI |
| Operator Country | |
| Operator Zip code | 54915 |
| Operator Code | A6AW |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | DIA |
| Departure City | DENVER |
| Departure State | CO |
| Departure Country | |
| Departure Time | 1918 |
| Departure Time Zone | MDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | MLI |
| Destination City | MOLINE |
| Destination State | IL |
| Destination Country | |
| Specific Phase of Flight | Cruise |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 2 2001 10:30AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 13L |
| Runway Length | 9001 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |