History of Flight
On August 26, 2013, about 1330 Pacific daylight time, a Grumman AA-1A, N61VT, collided with terrain near Desert Center, California. The pilot/owner was operating the airplane under Title 14 Code of Federal Regulations Part 91. The commercial pilot and one passenger sustained fatal injuries; the airplane was destroyed by impact forces and a post-crash fire. The local aerial photography flight departed Desert Center Airport at an undetermined time. Visual meteorological conditions prevailed, and no flight plan had been filed. Recent heavy rains and localized flooding had occurred in the area. The purpose of the flight was to assess damage to a solar power facility.
A Sheriff's Deputy observed the accident. He saw the airplane about 1,000 feet above the ground, making erratic maneuvers. The airplane traveled in a westerly direction and made a sharp U-turn to the east. The deputy observed the wings dip side-to-side, exposing the top and bottom of the airplane. The nose moved down toward the ground, then abruptly moved back up while proceeding easterly. The airplane started a second nosedive, turned counterclockwise exposing the top, and crashed into the ground. Eleven witnesses were working on a nearby fence line. Three reported the airplane made an abrupt turn from west to east. Seven reported hearing the engine stop, pop, or sputter; three did not report any engine cutouts.
Personnel Information
The 41-year-old pilot held a commercial pilot certificate with ratings for airplane single-engine land, multiengine land, and instrument airplane. He held a third-class medical certificate issued July 19, 2011, with no limitations or waivers. No personal flight records were located. The pilot reported on his medical application a total time of 750 hours with 0 hours logged in the previous 6 months.
Aircraft Information
The airplane was a Grumman AA1-A, serial number AA1A-0047. No maintenance logbooks were recovered. The engine was a Lycoming O-320-E2G, serial number L-48438-27A.
Meteorological Information
An aviation routine weather report (METAR) for Blythe (KBLH), California, 33 nautical miles east of the accident site, issued at 1352 reported wind from 330 degrees at 13 knots gusting to 18 knots; visibility 10 miles; sky clear; temperature 32°C (90°F); dew point 21°C (70°F); altimeter 29.88 inches of mercury.
Wreckage and Impact Information
The airplane came to rest upright. The cabin section was consumed by fire. The vertical stabilizer separated and was 30 feet aft of the empennage. The propeller separated from the flange and was about 3 feet in front of the engine. The engine was nose down with the propeller flange touching the dirt. The IIC established control continuity for the elevator and rudder. Debris prevented examination of the aileron system.
Additional Information
Carburetor ice: The carburetor icing probability chart from FAA Special Airworthiness Information Bulletin SAIB CE-09-35 shows a probability of icing at cruise/glide power and serious icing at glide power given the reported temperature/dew point (90/70°F).
Stalls: According to the FAA Airplane Flying Handbook (FAA-H-8083-3A), accelerated stalls occur at higher indicated airspeeds when excessive maneuvering loads are imposed. Stalls from abrupt maneuvers tend to be more rapid and severe, and failure to recover may result in loss of flight control.
Medical and Pathological Information
The Riverside County Sheriff-Coroner completed an autopsy and determined the cause of death as multiple blunt impact injuries. Toxicological testing of pilot specimens found no volatiles; tests for carbon monoxide or cyanide were not performed. Findings included diphenhydramine in liver, pseudoephedrine in muscle and liver, and ibuprophen in liver.
Tests and Research
Investigators from the NTSB, FAA, and Lycoming Engines examined the wreckage on August 28, 2013. No discrepancies were observed that would have precluded normal operation. Top spark plugs showed all center electrodes circular and clean; cylinder one's plug was wet with black fluid; others were gray. Borescope inspection revealed no mechanical deformation. The crankshaft rotated freely, valves moved in firing order, and thumb compression was obtained on all cylinders. Magnetos produced spark at all posts. The spinner was crushed aft. One propeller blade had leading edge polishing and was twisted toward low pitch/high rpm; the other blade was similarly twisted.