Incident Overview
A pilot of a tow plane washed the aircraft after observing it was dirty. Following the cleaning, the pilot did not secure the two engine cowl doors. During the initial climb while towing a glider, the cowl doors began flapping up and down.
Glider Release and Tow Plane Maneuvers
The glider pilot observed the flapping doors and released the tow line, landing safely. The tow plane pilot then reversed course to return for landing. Witnesses reported that while the airplane was reversing course, its pitch attitude steepened.
Stall, Spin, and Crash
The airplane stalled and entered a spin, continuing until it crashed on desert terrain adjacent to the airstrip. No other information about injuries, aircraft details, or contributing factors was provided in the source.
Conclusion
The accident resulted from a sequence of events beginning with the unsecured cowl doors, leading to a stall and spin during a course reversal. The glider pilot's timely release ensured a safe landing.