Accident Sequence
The purpose of the flight was to demonstrate a tow release failure of a glider from a tow plane and to land while still under tow. According to the flight instructor (CFI) in the glider, the standard procedure for the tow plane was to depart with 10 degrees of flaps and to turn left after takeoff. However, the tow pilot took off with 20 degrees of flaps and made a right turn, then entered a steep turn to the left. During the steep turn, slack developed in the tow rope. The CFI attempted to disconnect the tow rope but was unable. The student then actuated the release, and this time the rope released. The tow plane continued the left turn, nosed down, and struck the ground. The glider landed uneventfully. Neither the tow plane nor the glider was equipped with a radio.
Examination of the wreckage revealed no preimpact failure of the tow plane's flight controls or engine. Thirty feet of tow rope was found attached to the tow plane, and the rope had failed under tension.
Witness Accounts
Two witnesses reported that the tow pilot's hands always shook. One witness stated that his hands were shaking 'excessively' on the day of the accident.
Toxicological Findings
During toxicology tests, an undetermined amount of metoprolol was detected in the tow pilot's blood and urine. Metoprolol is a medication that is frequently approved by the FAA for use by pilots with high blood pressure; drugs like metoprolol may also be used to treat a tremor.