What happened
On January 21, 1974, a student pilot was conducting training flights at Birrfeld airfield. Following a series of dual-control landing practices, the pilot prepared for solo flight operations. During the taxi phase from the hangar to the start of runway 26, the pilot noted difficulty maintaining direction, requiring the use of brakes to execute right-hand turns because the rudder was ineffective.
As the takeoff commenced, the aircraft's longitudinal axis was misaligned with the runway by approximately 10 degrees to the right. In an attempt to correct this, the pilot applied left rudder while simultaneously pulling back on the control stick. This correction caused the aircraft to veer too sharply to the left. Despite the pilot applying full right rudder, the aircraft continued to deviate. After a ground roll of approximately 80 meters, the pilot instinctively pulled the aircraft off the ground to avoid hitting a runway marker. This resulted in an uncontrolled ground excursion in a stalled condition, where the left wing struck the ground. The aircraft spun around its vertical axis, impacting the ground with the nose, right wing, and tail, before coming to a stop parallel to the runway.
The investigation
Investigators examined the mechanical condition of the Piper J3 .3 (registration HB-ODD) and the pilot's training records. The investigation established that the tailwheel strut was difficult to rotate due to insufficient lubrication. Furthermore, the investigation noted that the pilot was training on two different aircraft types (the Piper J3C and a Cessna 150) during this phase of instruction, which was deemed inappropriate.
Findings
- The initial leftward deviation was caused by a combination of the aircraft's misalignment with the runway and the torque effect produced during engine power buildup.
- The pilot failed to successfully counter the leftward veer because the right wheel brake was not applied while the control stick was held in the aft position.
- The mechanical difficulty in steering was exacerbated by the poorly lubricated tailwheel strut.
- The pilot failed to abort the takeoff after the aircraft had already deviated from the runway centerline.
- The instructor's radio instruction to "keep straight" was less appropriate than a command to abort the takeoff.