What happened
On June 16, 2018, a Beechcraft A23-19 Musketeer was scheduled for a private flight from EPBC, carrying a pilot and two passengers, along with luggage. At the time of departure, the ambient temperature was 25°C. During the initial takeoff attempt, the pilot observed an unusually slow rate of climb and aborted the takeoff to perform a secondary inspection of the aircraft. No mechanical defects were found during this inspection.
Upon the second takeoff attempt, the aircraft initially achieved a climb rate of approximately 500 ft/min. However, the aircraft subsequently lost power and the rate of climb decreased significantly. Recognizing the performance degradation, the pilot decided to return to the departure airfield, where the aircraft landed safely without further incident.
The investigation
The investigation focused on the aircraft's performance capabilities under the prevailing environmental conditions. Investigators noted that the pilot had not provided a weight and balance sheet for the flight. Based on the estimated weight of the occupants and luggage, it was determined that the Maximum Takeoff Mass (MTOM) was exceeded by approximately 57.5 kg. Additionally, the investigation examined the impact of the 25°C ambient temperature on the aircraft's engine and aerodynamic performance.
Findings
- The primary cause of the incident was the exceedance of the MTOM combined with high ambient temperatures, which degraded the aircraft's climb performance.
- The aircraft was fully fueled with 224 liters of fuel at the time of the event.
- No mechanical or technical failures were identified in the propulsion system during the post-incident inspection.