What happened
On January 19, 1990, a NHAPECAN KW2 glider, registration PP-FJG, departed from the Novo Hamburgo aerodrome for a local instructional flight. The flight involved an instructor and a student. The session was specifically intended to include training for loss-of-control recovery maneuvers. During the flight, the aircraft entered a severe nose-low attitude accompanied by a wing spin. Witnesses observed the aircraft maintaining this unstable attitude until it struck high-voltage power lines and subsequently impacted the ground. The impact was nearly vertical, as evidenced by the damage to the aircraft's leading edge and the pattern of contact with the electrical wires. Both the instructor and the student sustained fatal injuries at the scene, and the aircraft was destroyed.
The investigation
CENIPA's investigation focused on the aircraft's weight and balance, the operational environment, and the human factors involved. Investigators found that the aircraft was flying with only three ballast plates instead of the four required by the manual for the specific weight of the crew, placing the center of gravity (CG) at the extreme rear limit of 28% MAC. This configuration made spin recovery significantly more difficult. Furthermore, the stall warning horn was found to be disabled, a common practice among operators of this aircraft type due to perceived unreliability.
Regarding the crew, the investigation noted a lack of continuity in the student's training records, meaning the instructor was unaware of the student's previous performance or psychological history. Evidence suggested the student had a history of panic during previous aerial activities. The investigation also identified deficiencies in the flight club's supervisory processes, including inadequate pre-flight briefings and inconsistent maintenance record-keeping.
Findings
- The aircraft's center of gravity was at the extreme rear limit, which increased the difficulty of recovering from a spin.
- The stall warning horn was non-functional/disabled.
- Inadequate instructional supervision and lack of standardized briefing/debriefing procedures.
- Potential human factor involving the student's psychological reaction (possible control freezing) during the recovery attempt.
- Improper weight and balance due to the use of insufficient ballast plates.