What happened
On 20 July 2017, a Piper PA-30 Twin Comanche, registration ZS-SWC, was conducting a multi-engine type conversion training flight from Springs (FASI) aerodrome in Gauteng. The crew, consisting of a flight instructor and a student pilot, climbed to 7,000 feet AMSL while heading toward Nigel. During the flight, the crew encountered radio communication difficulties and noticed the ammeter indicated the battery was not charging. After several unsuccessful attempts to reset the alternators, the instructor realized the aircraft was losing electrical power.
In response to the electrical issue, the instructor moved the landing gear selector to the down position while the aircraft still had sufficient power. The crew then returned to the aerodrome. During the landing sequence, the instructor performed the final checks, including a verbal confirmation of the gear position. However, upon touchdown on runway 2/21, the aircraft's landing gear did not support the weight of the plane. Approximately 50 metres down the runway, all three landing gear legs collapsed, causing the propellers to strike the ground. The aircraft slid roughly 100 metres on its belly before coming to a halt. There were no injuries to the two occupants.
The investigation
SACCA AIID investigators examined the aircraft's landing gear, electrical systems, and the runway surface. While the instructor initially reported that all indications appeared normal with weight on wheels prior to landing, physical evidence suggested otherwise. The investigation found that the landing gear warning horn was functional and that no mechanical failures in the landing gear or electrical systems prevented the gear from being extended.
Testing of the alternators revealed that while one unit was underperforming, the overall electrical system remained capable of powering the aircraft's essential systems, including the landing gear motor. Furthermore, the investigation noted that the information provided by the instructor regarding the gear status during the approach contradicted the physical evidence found at the scene. No scrape marks were found on the edges of the gear doors, which would have been present if the gear had been in transition during touchdown.
Findings
- The primary cause of the accident was the failure to extend the landing gear during the approach and landing phase.
- The crew's disregard for standard operating procedures contributed to the incident.
- Although the aircraft experienced an electrical charging issue, the system was still capable of supporting the landing gear operation.
- The physical evidence at the site, including propeller damage and runway scrape marks, confirmed the aircraft landed with the gear retracted.