Engine Failure Leads to Forced Landing of Ultralight in Ankara

Casualties unknown • ANKARA İLİ,GÖLBAŞI İLÇESİ, TR

A JMB Aircraft VL-3 ultralight experienced an engine failure due to fuel vapor lock, resulting in a forced landing in Gölbaşı, Türkiye.

What happened

On August 30, 2023, a JMB Aircraft VL-3-TE-915, registration TC-UME, departed from Etimesgut Airport (LTAD) bound for the KTO Karatay University landing strip. Shortly after takeoff, the aircraft experienced a significant drop in fuel flow, falling from 6.4 gal/hr to 0.9 gal/hr, accompanied by a sharp decline in fuel pressure from 41.4 psi to 6.6 psi. This led to a total engine failure, forcing the pilot to perform an emergency landing in an open field in the Tulumtaş area of Gölbaşı, Ankara. There were no fatalities or injuries, though the aircraft sustained light damage to the lower fuselage, propeller blades, and the engine cooling radiator.

The investigation

The UEİM investigation examined the aircraft's maintenance records, flight data from the Garmin GDU4/60 unit, and meteorological conditions. While the aircraft's maintenance was found to be up to date and the weather conditions were suitable for flight, investigators identified critical issues regarding the fuel and pilot documentation. Analysis of the fuel by the METU Petroleum Research Center revealed that the fuel contained levels of methanol and ethanol that exceeded standard limits, making it non-compliant with TSE EN 228 gasoline standards. Furthermore, while the aircraft was found to be overloaded at the start of the flight due to a failure to perform weight and balance calculations, investigators determined that the weight imbalance was not a contributing factor to the engine failure.

Findings

  • The primary cause of the engine failure was fuel vapor lock caused by high concentrations of ethanol and methanol in the fuel, which evaporated due to the aircraft being left in high ambient temperatures.
  • The pilot was operating with an expired medical certificate, rendering the pilot license invalid at the time of the occurrence.
  • The aircraft was operated in an overloaded state because the pilot failed to conduct necessary weight and balance calculations prior to departure.
  • The fuel used did not meet the required chemical specifications for the engine type.

Probable cause

The engine failure was caused by fuel vapor lock, resulting from high levels of ethanol and methanol in the fuel which evaporated under high temperatures, leading to a cessation of fuel flow.

Frequently asked questions

What happened in the 2023-08-30 aircraft accident near ANKARA İLİ,GÖLBAŞI İLÇESİ, TR?

A JMB Aircraft VL-3 ultralight experienced an engine failure due to fuel vapor lock, resulting in a forced landing in Gölbaşı, Türkiye.

What aircraft was involved and where did it happen?

The accident on 2023-08-30 involved a aircraft, registration TC-UME, at ANKARA İLİ,GÖLBAŞI İLÇESİ, TR.

What was the probable cause of the accident?

The engine failure was caused by fuel vapor lock, resulting from high levels of ethanol and methanol in the fuel which evaporated under high temperatures, leading to a cessation of fuel flow.

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