Pullman-Moscow Reg. Airport
Aircraft Accident/Incident Report

Pullman, Washington 99163
Tuesady, August 17, 2004 9:30 PDT

NTSB Narrative Summary Released at Completion of Accident

During a landing, just as the aircraft's two main wheels touched the surface of the runway, it suddenly jerked to the side and started to veer from the runway heading. The pilot therefore immediately added power and pulled the aircraft off the ground. He then climbed out to an altitude where he could visually inspect the gear legs and evaluate his situation. When he looked at the gear legs, he discovered that the left main gear strut oleo had come out of its housing, and the gear strut structure was hanging from the aircraft by two of its attach points. He therefore circled the area for awhile, waiting for emergency vehicles to get in place at the airport prior to his attempt to land on the remaining main gear. Once the equipment was in place, he landed on the grass alongside of the paved runway. The aircraft touched down on the right main gear, and the pilot kept the other gear leg elevated as long as possible. Eventually, as the aircraft slowed, the left gear strut dug into the terrain and collapsed. A post-accident inspection of the gear system determined that the landing gear shock strut retaining nut safety clip (snap ring) had failed, thus allowing the shock strut retaining nut to back off of its threads. Without this retaining nut in place, the oleo piston was free to drop out of its housing, leaving the landing gear only partially attached to the fuselage.

NTSB Probable Cause Narrative

The failure of a landing gear oleo retaining nut safety clip (snap ring) at an unknown point in time, leading to the partial separation of the landing gear strut while in flight, and the full collapse of the strut during the subsequent landing. Factors include the grassy terrain that the pilot chose to execute the landing on.

Event Information

Type of Event Accident
Event Date 8/17/2004
Event Day of the Week Tuesday
Time of Event 930
Event Time Zone Pacific Daylight Time
Event City Pullman
Event State WASHINGTON
Event Country --
Zipcode of the event site 99163
Event Date Year 2004
Event Date Month 8
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 464455N
Event Location Longitude 1170808W
Event Location Airport Pullman-Moscow Reg.
Event Location Nearest Airport ID PUW
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 2555
Weather Briefing Completeness Unknown
Investigator's weather source Pilot
Time of the weather observation
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID --
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
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) 20
Air Temperature at event time (in degrees celsius) 24
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 270
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 5
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 2
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 17233
NTSB Notification Source FAA Operations Center
NTSB Notification Date Aug 17 2004 12:00AM
NTSB Notification Time 1000
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Jan 27 2005 3:52PM
User who most recently changed record NTSB\JOHB
Basic weather conditions Visual Meteorological Cond
FAA District Office Spokane FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N11872
NTSB Number SEA04LA162
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Universal Moulded Pdts.
Aircraft Model Monocoach
Aircraft Series Identifier --
Aircraft Serial Number 5012
Certified Max Gross Weight 3200
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 4
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection May 1 2004 12:00AM
Airframe hours since last inspection 2
Airframe Hours 1904
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Carsons Investments Inc.
Aircraft Owner Street Address 1947 McCulloch Blvd
Aircraft Owner City Lake Havasu City
Aircraft Owner State CA
Aircraft Owner Country USA
Aircraft Owner Zipcode 86403
Operator is an individual? No
Operator Name William C. Piper
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address P.O. Box 93
Operator City Porthill
Operator State ID
Operator Country USA
Operator Zip code 83853
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? --
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 No
Departure Airport Code 1S1
Departure City Porthill
Departure State ID
Departure Country USA
Departure Time 745
Departure Time Zone PDT
Destination Same as Local Flt crash at destination city
Destination Airport Code PUW
Destination City Pullman
Destination State WA
Destination Country USA
Specific Phase of Flight Landing
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record --
User who most recently changed record --
Since inspection or accident Time of Accident
Event Location Runway Number and Location 23
Runway Length 6730
Runway Width 100
Sight Seeing flight No
Air Medical Flight No
Medical Flight --