What happened
On July 30, 1961, a Klemm 35-D, registration HB-UXB, was performing a series of scheduled aerobatic maneuvers during an airshow at Sarzana Aerodrome, Italy. The aircraft, operated by Airtronics S.A., was being flown by a single pilot. After completing several maneuvers, including loops and rolls, the aircraft was flying in a straight, level path at an altitude of approximately 300 meters.
As the aircraft reached the western end of the grass runway, it experienced a sudden, sharp descent. The aircraft entered an inverted attitude, banking at an angle of approximately 70 to 80 degrees relative to the ground, and began a right-hand turn. During this sequence, the aircraft struck the terrain at high speed, leading to a violent impact and a subsequent intense fire that destroyed the airframe.
The investigation
The investigation, conducted by a commission involving Italian authorities, examined the wreckage and interviewed witnesses, including members of the Aero Club of Sarzana. Technical inspections of the Klemm 35-D revealed that the engine, propeller, and airframe were in good working condition prior to the accident, with no mechanical failures or maintenance issues identified. The investigation also reviewed the pilot's flight logs and the aircraft's instruction manual.
Findings
- The aircraft's instruction manual specifically prohibited the execution of the maneuver attempted by the pilot.
- The altitude maintained during the maneuver was insufficient to allow for an emergency recovery.
- The pilot lacked recent experience with this specific aircraft, having flown it only 35 hours prior to the accident.
- The pilot was not in possession of the required Swiss license for operating a Swiss-registered aircraft.
- The impact was characterized by high horizontal velocity, which prevented the pilot from avoiding the ground despite an attempt to pull up.