Clarion Municipal Airport
Aircraft Accident/Incident Report

Clarion, Iowa 50525
Thursday, October 21, 2010 14:15 CDT

NTSB Narrative Summary Released at Completion of Accident

A witness reported seeing the airplane suddenly enter a counterclockwise spinning dive toward the ground, make about four revolutions, and then impact the ground. A postaccident examination of the airplane revealed significant damage to the cockpit area, including the instrument panel and the area containing the engine controls. The left engine magneto switch was found positioned so that only one magneto of the dual magneto ignition system was active, the left propeller control was in an aft position, and the fuel flow indicator for the left engine showed no fuel flow. The most recent annual inspection of the airplane was performed more than 3 years before the accident; however, no preimpact anomalies were found during the postaccident examinations. Based on the counterclockwise rotation of the airplane, and the position of the engine levers, the pilot failed to maintain control of the airplane following an undetermined anomaly with the left engine.

NTSB Probable Cause Narrative

The pilot's failure to maintain control of the airplane. Contributing to the accident was the loss of left engine power for undetermined reasons.

Event Information

Type of Event Accident
Event Date 10/21/2010
Event Day of the Week Thursday
Time of Event 1415
Event Time Zone Central Daylight Time
Event City Clarion
Event State IOWA
Event Country --
Zipcode of the event site 50525
Event Date Year 2010
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport Clarion Municipal Airport
Event Location Nearest Airport ID CAV
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles 2
Degrees magnetic from airport --
Airport Elevation 270
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1415 Central Daylight Time
Direction of event from weather observation facility (degrees) 90
Weather Observation Facility ID CAV
Elevation of weather observation facility 1162
Distance of event from weather observation facility (units?) 2
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 13
Dew Point at event time (in degress fahrenheit) -3
Wind Direction (degrees magnetic) 340
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 8
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.05
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report METAR KCAV 211755Z AUTO 32008G14KT 10SM CLR 12/M03
Event Highest Injury Fatal
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal 1
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 29004
NTSB Notification Source FAA-CEN-ROC
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Nov 9 2011 2:46PM
User who most recently changed record johb
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N784CB
NTSB Number CEN11FA040
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed Unknown
Flight plan Was Activated? No
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BEECH
Aircraft Model 95-B55 (T42A)
Aircraft Series Identifier --
Aircraft Serial Number TC-977
Certified Max Gross Weight --
Aircraft Category Airplane
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 6
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Jul 1 2007 12:00AM
Airframe hours since last inspection --
Airframe Hours 8854
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name NORTH IOWA AIR INC
Aircraft Owner Street Address --
Aircraft Owner City WOOLSTOCK
Aircraft Owner State IA
Aircraft Owner Country USA
Aircraft Owner Zipcode 50599
Operator is an individual? Yes
Operator Name Arden E. Tweeten
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address --
Operator City Woolstock
Operator State IA
Operator Country USA
Operator Zip code 50599
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code CAV
Departure City Clarion
Departure State IA
Departure Country USA
Departure Time 1410
Departure Time Zone CDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code CAV
Destination City Clarion
Destination State IA
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Nov 2 2011 1:00PM
User who most recently changed record johb
Since inspection or accident Last Inspection
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --