Individually Owned: 150,657
Corporate Owned: 137,281
Yakima Airport
Aircraft Accident/Incident Report
Cowiche, Washington 98923
Wednesday, August 17, 2011 18:45 PDT
NTSB Narrative Summary Released at Completion of Accident
During a training flight, the airplane's occupants heard a hammering sound accompanied by an airframe vibration and reduction in engine power. The certified flight instructor took control of the airplane from the student and began to initiate a return to the airport. He decided that it was unlikely that they would be able to safely return, and he elected to perform a forced landing into a field. The airplane landed hard.
Examination of the engine revealed that the exhaust valve head most likely separated from its stem during flight, resulting in catastrophic failure to its associated cylinder components. Discoloration within the rocker area, exhaust valve guide, and cooling fins was consistent with heat damage, most likely caused by a stuck or sticking exhaust valve. The engine was manufactured in 1948, and its serial number did not match any records on file with the manufacturer. The maintenance records did not reveal a complete history of the engine's total flight time.
NTSB Probable Cause Narrative
A partial loss of engine power during maneuvering flight due to an exhaust valve failure.
Event Information
| Type of Event | Accident |
| Event Date | 8/17/2011 |
| Event Day of the Week | Wednesday |
| Time of Event | 1845 |
| Event Time Zone | Pacific Daylight Time |
| Event City | Cowiche |
| Event State | WASHINGTON |
| Event Country | -- |
| Zipcode of the event site | 98923 |
| Event Date Year | 2011 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 464033N |
| Event Location Longitude | 1204229W |
| Event Location Airport | Yakima |
| Event Location Nearest Airport ID | YKM |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 11 |
| Degrees magnetic from airport | -- |
| Airport Elevation | 1099 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1853 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | 313 |
| Weather Observation Facility ID | YKM |
| Elevation of weather observation facility | 1099 |
| Distance of event from weather observation facility (units?) | 11 |
| Time Zone of the weather observation | PDT |
| 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) | 29 |
| Dew Point at event time (in degress fahrenheit) | 4 |
| Wind Direction (degrees magnetic) | 320 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 12 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.94 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | METAR KYKM 180153Z 33012KT 10SM CLR 29/04 A2994 RM |
| 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) | 29776 |
| NTSB Notification Source | FAA AMN Operations Center |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Apr 6 2012 5:09PM |
| User who most recently changed record | coos |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N1444K |
| NTSB Number | WPR11LA391 |
| 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 | LUSCOMBE |
| Aircraft Model | 8A |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 4171 |
| Certified Max Gross Weight | 1200 |
| 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 | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Jun 30 2011 12:00AM |
| Airframe hours since last inspection | 49 |
| Airframe Hours | 4215 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | C91-A |
| Aircraft Owner Name | Mike Olson |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Yakima |
| Aircraft Owner State | WA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 98901-3704 |
| Operator is an individual? | Yes |
| Operator Name | Yakima Aerosport LLC. |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Yakima |
| Operator State | WA |
| Operator Country | USA |
| Operator Zip code | 98901 |
| 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) | Instructional |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | YKM |
| Departure City | Yakima |
| Departure State | WA |
| Departure Country | USA |
| Departure Time | 1800 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | -- |
| Destination City | Cowiche |
| Destination State | WA |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Apr 6 2012 5:10PM |
| User who most recently changed record | coos |
| 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 | -- |