Occurrence
On 12 March 2025, at approximately 1425Z, a Piper Seneca II aircraft (registration ZS-SNR) was conducting a type conversion training flight at Lanseria International Airport (FALA), Gauteng Province. The flight, operated under Part 141 of the Civil Aviation Regulations, departed at 1400Z and performed four circuits with touch-and-go landings on Runway 25. During the fifth circuit, a full-stop landing was planned.
Sequence of Events
According to the flight instructor, the pre-flight inspection revealed no anomalies. The pilot, holding a Private Pilot Licence, was the pilot flying. After take-off, the aircraft climbed to 1000 ft AGL and completed four circuits. On the downwind leg of the fifth circuit, pre-landing checks were completed, and three green landing gear indicator lights confirmed all gear extended and locked. First stage flaps were selected. On final approach at approximately 400 ft AGL and 80 KIAS, the approach continued to landing. During the landing flare, the main wheels touched down, followed by the nose wheel, which collapsed during the landing roll. The propellers struck the runway, and the aircraft skidded on its nose cone, stopping approximately 100 m from the initial touchdown point.
Damage and Injuries
The aircraft sustained substantial damage to the nose cone and propeller blades. The flight instructor and the pilot were not injured.
Post-Accident Investigation
The aircraft was recovered to a SACAA-approved maintenance organisation and placed on jacks for gear retraction tests. Access panels under the nose section were removed, revealing a leak in the pressurised hydraulic retraction pipe (MIL-H 5606 fluid). The leak appeared to be from rubbing against an object, possibly a nearby clamp, but no evidence supported this. The leak was determined not to have resulted from impact damage during the accident. The hydraulic pipes for the main landing gears were undamaged.
Landing Gear System Description
The Seneca II is equipped with hydraulically operated, fully retractable tricycle landing gear. An electrically powered reversible hydraulic pump, activated by a gear selector switch, provides pressure for extension and retraction. Gear extension or retraction takes six to seven seconds. A squat switch on the left main gear prevents inadvertent retraction when on the ground.
Squat Switch Examination
The squat switch was examined and found serviceable.
Conclusion
A hydraulic retraction pipe for the nose gear with pressurised fluid was leaking, causing loss of hydraulic pressure required to keep the nose gear extended and locked, leading to the collapse.