Aircraft Accident/Incident Report

Mosinee, Wisconsin 54455
Friday, February 25, 1994 22:23 CST

NTSB Narrative Summary Released at Completion of Accident

THE FLIGHT CREW SAW SMOKE IN THE COCKPIT WHILE DESCENDING FROM CRUISE AND DECLARED AN EMERGENCY. THE COPILOT DISCOVERED THE SOURCE OF THE SMOKE TO BE A RED-HOT PUSH BUTTON SELECTOR INDICATOR (PBSI) SWITCH FOR THE FLIGHT IDLE BAULK TEST. HE DISCHARGED A PORTABLE FIRE EXTINGUISHER ON THE SWITCH AND THE SMOKE STOPPED. THE SWITCH WAS SUBSEQUENTLY REMOVED BY MAINTENANCE PERSONNEL AND FOUND TO SCORCHED AND MELTED. ADJACENT WIRING WAS ALSO HEAT DAMAGED. THE MANUFACTURER HAD PREVIOUSLY ISSUED TWO SERVICE BULLETINS WHICH DEALT WITH PBSI SWITCH MALFUNCTIONS ASSOCIATED WITH WATER INGRESS TO THE COCKPIT IN THE VICINITY OF THE SWITCHES. THE OPERATOR HAD NOT COMPLIED WITH THE VOLUNTARY SERVICE BULLETINS AT THE TIME OF THE INCIDENT.

NTSB Probable Cause Narrative

the inadequate design of the PBSI electrical switch(es), and the operator's failure to expeditiously implement corrective Service Bulletins.

Event Information

Type of Event Incident
Event Date 2/25/1994
Event Day of the Week Friday
Time of Event 2223
Event Time Zone Central Standard Time
Event City MOSINEE
Event State WISCONSIN
Event Country --
Zipcode of the event site 54455
Event Date Year 1994
Event Date Month 2
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 2100 Central Standard Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID CWA
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation CST
Lighting Conditions Night/Bright
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 20
Air Temperature at event time (in degrees celsius) --
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 360
Variable Wind Indicator Unknown
Wind Speed (knots) 10
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 2
Injury Total None 16
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 5019
NTSB Notification Source --
NTSB Notification Date Feb 25 1994 12:00AM
NTSB Notification Time 2315
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 6 2000 10:39AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N854AW
NTSB Number CHI94IA095
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Minor
Aircraft Fire Unknown
Aircraft Explosion None
Aircraft Manufacturer's Full Name BRITISH AEROSPACE
Aircraft Model ATP
Aircraft Series Identifier ATP
Aircraft Serial Number 2028
Certified Max Gross Weight 50550
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 68
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Unknown
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name WILMINGTON TRUST CO.
Aircraft Owner Street Address RODNEY SQ. NORTH
Aircraft Owner City WIMINGTON
Aircraft Owner State DE
Aircraft Owner Country
Aircraft Owner Zipcode 19890
Operator is an individual? --
Operator Name UNITED FEEDER SERVICE
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address P.O. BOX 6639
Operator City CHICAGO
Operator State IL
Operator Country
Operator Zip code 60666
Operator Code UFS
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/Cargo
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code ORD
Departure City CHICAGO
Departure State IL
Departure Country
Departure Time 2045
Departure Time Zone CST
Destination Same as Local Flt crash at destination city
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Descent
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 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --