What happened
On 2 October 2019, an ICP Srl Savannah S, registration EI-GEO, was performing a local flight from Navan Airfield, Co. Meath. During the takeoff roll, the aircraft reached an altitude of approximately 100 feet before the engine power unexpectedly dropped toward idle. In an attempt to manage the loss of thrust, the pilot lowered the aircraft's nose to perform an emergency landing on the remaining runway.
Upon touchdown, the pilot found the braking action significantly reduced, describing the sensation as braking on ice. The aircraft continued along the grass runway, eventually striking a wire fence located at the runway's end. The impact caused the nose landing gear to collapse under the fuselage and the propeller to strike the ground. The aircraft came to a halt nine meters beyond the fence. The pilot, who was the sole occupant, was uninjured and able to exit the aircraft without assistance. The aircraft sustained substantial damage.
The investigation
The AAIU examined the engine, the fuel system, and the environmental conditions at the time of the accident. The investigation confirmed that the aircraft's maintenance records were up to date and the engine was functioning according to its design. Investigators also reviewed the meteorological data, noting that while the weather was generally good, there was heavy dew on the ground.
Technical analysis focused on the engine's induction system, which relies on ambient heat within the engine compartment to prevent ice formation in the carburettors. The investigation also looked into the effectiveness of the braking and the presence of the fence at the airfield's boundary.
Findings
- The primary cause of the power loss was likely carburettor icing, which can form insidiously when high humidity and dew are present.
- The use of Mogas, which is more volatile and has a higher water content than Avgas, increased the risk of induction icing.
- It is probable that the engine compartment temperature had not risen sufficiently before takeoff to prevent ice from forming or to clear existing ice.
- Reduced friction from the heavy dew on the grass runway contributed to the ineffective braking.
- The aircraft's high-wing design allowed it to clear the large wooden fence posts, though the wire fence itself caused the structural damage.