NTSB Identification: SEA88FA160.
The docket is stored on NTSB microfiche number 37379.
Accident occurred Tuesday, August 23, 1988 in JOHN DAY, OR
Probable Cause Approval Date: 10/02/1989
Aircraft: AERO COMMANDER 100-180, registration: N4175X
Injuries: 3 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

WHILE ELK SPOTTING IN MOUNTAINOUS TERRAIN, THE AIRCRAFT COLLIDED WITH TREES IN A NOSE LOW TURN SIMILAR TO THE INTERMEDIATE STAGES OF A STALL. A SEVERE POST IMPACT FIRE ERUPTED. THE DENSITY ALTITUDE AT THE ACCIDENT SITE ELEVATION WAS APPROXIMATELY 10,100 FEET. ALL SPARK PLUGS WERE FOUND TO BE EXCESSIVELY WORN AND FIRED INTERMITTENTLY DURING TESTING. TWO OF THE SPARK PLUGS WERE FOUND TO BE LEAD FOULED. THE FLAPS WERE FOUND IN THE FULL DOWN POSITION AND TREE LIMBS, APPROXIMATELY 3 INCHES IN DIAMETER, WERE FOUND WITH SMOOTH SLASHES DIAGONALLY THROUGH THEM.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

AIRSPEED..NOT MAINTAINED..PILOT IN COMMAND

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

STALL..INADVERTENT..PILOT IN COMMAND



Contributing Factors

WEATHER CONDITION..HIGH DENSITY ALTITUDE


Contributing Factors

IGNITION SYSTEM,SPARK PLUG..LEADED


Contributing Factors

IGNITION SYSTEM,SPARK PLUG..WORN


Contributing Factors

MAINTENANCE..IMPROPER..PILOT IN COMMAND

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