NTSB Identification: DEN92FA020.
The docket is stored on NTSB microfiche number 45835.
Accident occurred Wednesday, December 25, 1991 in MONTE VISTA, CO
Probable Cause Approval Date: 04/23/1993
Aircraft: GRUMMAN AMERICAN AA-5A, registration: N9991U
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 ON A POST TAKEOFF CROSSWIND CLIMB, THE PILOT INADVERTENTLY STALLED THE AIRCRAFT AT A LOW ALTITUDE. THE AIRCRAFT IMPACTED VERTICALLY IN A FROZEN OPEN FIELD. INVESTIGATION REVEALED THE AIRCRAFT TO BE 90 POUNDS OVER MAXIMUM GROSS WEIGHT; THE PILOT TO BE SUFFERING FROM PHYSICAL IMPAIRMENT DUE TO CARBON MONOXIDE POISONING; THE PILOT TO BE LOW IN TOTAL EXPERIENCE, EXPERIENCE IN TYPE; AND RECENT EXPERIENCE. TOXICOLOGY TESTS REVEALED 16% CARBOXYHEMOGLOBIN IN THE PILOT'S BLOOD. PASSENGER TEST RESULTS WERE NEGATIVE. THAT SATURATION LEVEL CAN CAUSE DEGRADATION IN JUDGMENT AND PERFORMANCE. THE PILOT WAS A MECHANIC AND HAD BEEN EXPOSED TO RUNNING ENGINES IN A NON-VENTILATED SHOP THE DAY/EVENING PRIOR TO THE ACCIDENT.

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

AN INADVERTENT STALL BY THE PILOT IN COMMAND AT AN ALTITUDE INSUFFICIENT TO EFFECT RECOVERY. FACTORS WERE: AIRCRAFT GROSS WEIGHT ABOVE MAXIMUM; PHYSICAL IMPAIRMENT OF THE PILOT; LACK OF TOTAL EXPERIENCE; LACK OF RECENT EXPERIENCE; AND LACK OF EXPERIENCE IN TYPE.

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