Aircraft Accident/Incident Report

St. Paul, Minnesota 55107
Tuesady, April 5, 1988 15:15 CDT

NTSB Narrative Summary Released at Completion of Accident

THE AIRPLANE WAS BEING OPERATED AS AN AIR AMBULANCE WHEN IT SUSTAINED SUBSTANTIAL DAMAGE DURING AN UNCOMMANDED HARD PITCHOVER. THE AIRPLANE WAS OPERATING IN VISUAL CONDITIONS ABOVE A SOLID CLOUD LAYER USING INSTRUMENT FLIGHT RULES. THE AIRPLANE RECOVERED FROM THE EXCURSION AND CONTINUED ON TO ITS DESTINATION. THE ATP RATED PILOT, THREE MEDICAL ATTENDANTS AND ONE PATIENT WERE NOT INJURED. TESTING OF THE PILOT'S WHEEL TRIM SWITCH SHOWED THE SWITCH WOULD STICK IN THE CLOSED OR ACTUATED POSITION AND NOT RETURN TO THE 'CENTER OFF' POSITION. THIS OCCURRED DURING TEMPERATURE CYCLING FROM ROOM TEMPERATURE TO BELOW FREEZING AND BACK AGAIN. THE CABIN HEATER HAD FAILED WITH AN OUTSIDE AIR TEMPERATURE OF -26 DEGS CELSIUS AND THE CABIN WAS COLD.

NTSB Probable Cause Narrative

MECHANICAL FAILURE AND STICKING OF THE PILOTS THUMB OPERATED TRIM SWITCH CAUSING NOSE DOWN PITCH COMMAND. THE FAILURE OF THE CABIN HEATER AND THE LOW CABIN TEMPERATURE ARE CONTRIBUTING FACTORS.

Event Information

Type of Event Accident
Event Date 4/5/1988
Event Day of the Week Tuesday
Time of Event 1515
Event Time Zone Central Daylight Time
Event City ST. PAUL
Event State MINNESOTA
Event Country --
Zipcode of the event site 55107
Event Date Year 1988
Event Date Month 4
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 0
Degrees magnetic from airport 0
Airport Elevation 0
Weather Briefing Completeness Not pertinent
Investigator's weather source Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Unknown
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 0
Air Temperature at event time (in degrees celsius) -8
Dew Point at event time (in degress fahrenheit) -18
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) 0
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 5
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 2481
NTSB Notification Source --
NTSB Notification Date Apr 6 1988 12:00AM
NTSB Notification Time 946
Fiche Number and/or location -used to find docket information 39640
Date of most recent change to record Dec 13 2000 11:40AM
User who most recently changed record dbo
Basic weather conditions Instrument Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N181LL
NTSB Number CHI88FA091
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BEECH
Aircraft Model B90
Aircraft Series Identifier B90
Aircraft Serial Number LJ-440
Certified Max Gross Weight 9650
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 7
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 140
Airframe Hours 5950
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name CRITICAL CARE INC.
Aircraft Owner Street Address 336 CHESTER
Aircraft Owner City ST. PAUL
Aircraft Owner State MN
Aircraft Owner Country
Aircraft Owner Zipcode 55107
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code
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 Non-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 No
Departure Point Same as Event No
Departure Airport Code MOT
Departure City MINOT
Departure State ND
Departure Country
Departure Time 1400
Departure Time Zone CDT
Destination Same as Local Flt --
Destination Airport Code STP
Destination City ST. PAUL
Destination State MN
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:35AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length 0
Runway Width 0
Sight Seeing flight No
Air Medical Flight No
Medical Flight --