Karpf Baby crash during aerotow near Hausen a.A. airfield, pilot injured
On May 26, 1973, a Karpf-Flugzeugbau Karpf Baby crashed near Hausen a.A. airfield in Switzerland during an aerotow launch. The glider released from the tow approximately 2 km from the airfield and attempted a turn back towards the field. It stalled and crashed from a height of about 50 meters. The pilot sustained serious injuries, and the aircraft was destroyed. The investigation noted that the glider's speed fell below the minimum required during the turn.
- Aerotow initial climb: The Karpf-Baby HB-504 began an aerotow training flight from Hausen a. Albis on runway 09 and entered a normal initial climb behind the towplane.
- High tow speed: During the climb in bumpy conditions, the towplane flew at about 110–120 km/h, higher than recommended for the Karpf-Baby in such turbulence.
- Uncommanded tow release: At about 100 m above ground and roughly 2 km from the airfield, the glider unexpectedly became detached from the towline for undetermined reasons.
- Turn back toward field: After release, the glider flew straight for about 500 m and then the pilot initiated a low-altitude turn back toward the airfield.
- Stall in turn: While completing the turn at about 50 m above ground with an aft-center-of-gravity loading, the glider’s airspeed dropped below minimum and it abruptly pitched nose-down.
- Crash - serious injury: The glider dived into a field at a steep nose-down attitude, was destroyed, and the pilot sustained serious injuries.