What happened
On 5 October 2023, a Beechcraft Baron G58, registration PK-LRV, was conducting multi-engine training maneuvers at Cakrabhuwana Airport in Cirebon, Indonesia. The flight, operated by Angkasa Aviation Academy, involved a flight instructor and a student pilot performing various exercises, including stall training and simulated engine failures.
During the training session, the crew performed several maneuvers that intentionally triggered the aircraft's landing gear warning system. Specifically, reducing power to idle during simulated one-engine-inoperative exercises caused the warning horn and "gear up" annunciator to activate. During the final training leg, the aircraft touched down with the landing gear still retracted, resulting in significant damage to the aircraft's lower fuselage and propellers.
The investigation
The KNKT investigation focused on the cockpit environment and the physiological state of the flight instructor. Investigators found that the training session included 16 separate instances where the landing gear warning was triggered, totaling over 33 minutes of audible alerts. This high frequency of non-threatening alerts created a state of alarm fatigue.
Furthermore, the investigation examined the instructor's workload and physical condition. On the day of the accident, the instructor was fasting and had been managing administrative responsibilities, including a scheduled management meeting. The investigation also reviewed the crew's coordination and adherence to checklists during the final approach.
Findings
- The primary cause of the accident was a failure to extend the landing gear due to the crew's desensitization to the landing gear warning horn.
- Repeated activations of the warning horn during simulated engine-out exercises caused the pilots to become habituated to the alert, rendering the safety system ineffective.
- The flight instructor's attention was divided by administrative duties and a scheduled management meeting.
- The instructor's fasting state may have contributed to degraded human performance and reduced the ability to manage the high workload.
- A lapse in the execution of the landing checklist during the final approach prevented the identification of the gear-up configuration.