What happened
On 25 February 2025, a Diamond DA42 Twin Star, registration ZS-TDI, was conducting a type conversion training flight at Lanseria International Airport (FALA) in Gauteng. The flight, involving a flight instructor and a trainee pilot, was performing a series of touch-and-go landings under visual meteorological conditions.
During the second circuit, air traffic control instructed the crew to execute a shortened approach to accommodate an inbound commercial aircraft. To facilitate this, the instructor directed the pilot flying to reduce power and prepare for a flapless landing. As engine power was reduced to idle, the aircraft's low-power audible warning horn activated. The crew, anticipating this specific warning due to the power setting, chose to disregard the horn.
Crucially, the crew failed to extend the landing gear during the approach. The error was only discovered during the landing flare, at which point it was too late to deploy the gear. The aircraft struck the runway with the gear retracted, causing both propellers to impact the ground. The aircraft slid approximately 800 metres before coming to a stop. There were no fatalities and no injuries to the crew, though the aircraft sustained substantial damage to the propellers, engine cowlings, and the underside of the fuselage.
The investigation
The SACAA AIID investigation examined the cockpit procedures, the aircraft's mechanical state, and the environmental conditions. The investigation confirmed that the aircraft's low-power warning horn was functioning correctly and was designed to alert pilots when the gear is retracted during low-power settings. The investigation also reviewed the crew's credentials, noting that both individuals held Commercial Pilot Licences and were experienced in flight instruction, though their experience on this specific aircraft type was limited.
Findings
- The primary cause of the accident was the omission to extend the landing gear during the landing phase.
- The crew's decision to disregard the audible warning horn prevented them from recognizing the retracted gear status.
- High workload and time pressure, resulting from the ATC instruction to shorten the approach, contributed to the error.
- A breakdown in Crew Resource Management (CRM) occurred because the crew lacked defined roles and mutual verification during the checklist review, relying instead on an informal, unverified process.