Synopsis
On 24 September 2018 at 0515Z, a Micro Aviation Bantam B22J (registration ZU-EGU) departed from Hoedspruit Civil Aerodrome in Gauteng, South Africa for a training flight with a pilot and a student on board. About 10 minutes into the flight, the engine emitted a loud bang and began running rough before stopping. The pilot attempted a forced landing in an open field, but it was unsuccessful; the aircraft came to rest with its tail high and nose perpendicular to the ground. Neither occupant was injured, but the aircraft sustained substantial damage.
History of Flight
The flight departed at 0500Z and climbed to 2000 feet AMSL, cruising at 50 knots. After the engine failure, the pilot identified a field and initiated a forced landing. The accident site was located on a farm approximately 5 nautical miles southwest of Hoedspruit Civil Aerodrome at coordinates S24°22’42.00” E30°57’00.07” at an elevation of 1780 feet. Weather conditions were reported as surface wind 170/08 knots, temperature 25°C, dew point 16°C, visibility 10 kilometers, CAVOK, QNH 1021 hPa.
Investigation
The engine, a Jabiru 2200 (serial number 22A2484) with 555.6 hours since new, was disassembled by an approved maintenance organization. Examination revealed that the number 4 cylinder exhaust valve was broken, which caused the cylinder to lose compression and led to the engine failure. The broken valve was misplaced after disassembly and was not available for further testing. The last engine inspection was performed on 16 August 2018 at 539.8 hours. Maintenance records showed that the Jabiru Cylinder Head Inspection service bulletin (JSL014-5) was complied with during the 500-hour inspection on 15 January 2018.
Findings
The pilot held a valid National Pilot Licence with a type endorsement for the aircraft and a class 2 medical certificate. The pilot had accumulated 5076.7 total hours, with 2218 hours on type. The aircraft held a valid Authority to Fly with an expiry date of 15 August 2019. The investigation determined that the engine failure was caused by the failure of the number 4 cylinder exhaust valve; however, the underlying reason for the valve failure could not be determined.
Probable Cause
The probable cause was an engine failure that resulted in an unsuccessful forced landing. The engine failure was attributed to the failure of the number 4 cylinder exhaust valve; the cause of the valve failure could not be determined.
Safety Recommendation
The report recommended that the regulator consider adopting limitations similar to those published by the Australian Civil Aviation Safety Authority (CASA) in November 2014 for Jabiru engines, which included restrictions to day VFR operations in non-populated areas and limitations on passenger and student operations.