What happened
On 17 November 2018, a Cessna 150L, registration ZS-NRX, departed from Marble Hall Aerodrome in Limpopo Province, bound for Rand Aerodrome. During the departure on Runway 22, the pilot initiated the take-off roll from the midpoint of the runway. Although the aircraft rotated at approximately 60 knots, it reached an altitude of only about 10 metres (35 feet) before failing to gain further height.
In an attempt to increase lift, the pilot deployed full flaps during this low-altitude phase. However, this action induced significant drag, causing the aircraft to descend. The aircraft subsequently struck trees to the left of the runway centerline and impacted the ground approximately 300 metres from the runway threshold. The impact caused substantial damage to the aircraft, but the pilot and passenger sustained no injuries.
The investigation
SACAA AIID investigators examined the flight parameters and runway availability at the time of the accident. The investigation established that the pilot had a total take-off distance available of 3,281 feet. However, the pilot only utilized 1,640.5 feet for the take-off roll.
Calculations performed during the inquiry revealed that to safely clear a 50-foot obstacle ahead of the runway, a take-off distance of 2,329.37 feet was required. The investigation also confirmed that the aircraft's mechanical systems, including flight controls and engine, were functioning correctly prior to the impact, with no mechanical malfunctions reported by the pilot.
Findings
- The primary cause of the accident was the miscalculation of the required take-off distance and the performance necessary for a safe climb-out.
- The pilot utilized significantly less runway than was necessary to clear obstacles, leaving the aircraft with insufficient energy to maintain a positive rate of climb.
- The deployment of full flaps at a low altitude created excessive drag, which contributed to the loss of altitude.
- While sufficient runway was available to perform a safe departure, the decision to begin the roll at the runway midpoint prevented the aircraft from achieving the necessary performance.