What happened
On November 21, 2018, a Cessna 172R aircraft, registration VT-RGC, was conducting a solo cross-country training flight from Begumpet Airport toward Gobur, Karnataka. The flight was operated by M/s Wings Aviation Pvt. Ltd. and commanded by a student trainee pilot.
During the climbing phase, while the aircraft was at approximately 6,300 feet, the engine began to vibrate significantly. Within a few seconds, the engine ceased operation and the propeller stopped rotating. The pilot attempted to level the aircraft and tried to restart the engine, but these efforts were unsuccessful. After an initial attempt to contact Shamshabad Approach went unanswered, the pilot issued a triple "May Day" call to declare the engine failure.
As the aircraft continued to lose altitude, the pilot determined that returning to Begumpet Airport—located about 18 nautical miles away—was not possible. While searching for a suitable landing site, the pilot lost radio communication with Air Traffic Control. The aircraft subsequently performed a forced landing in a paddy field at Mokila, near the outskirts of Hyderabad. During the impact, the aircraft's left wing struck a tree, resulting in substantial structural damage to the airframe, including the landing gear, fuselage, and wings. The pilot sustained minor injuries and was able to exit the aircraft independently.
The investigation
AAIB India investigators examined the wreckage and the engine components to determine the cause of the power loss. A strip examination of the engine revealed that the crankshaft could not be rotated and that the engine had suffered internal damage. The investigation focused on the mechanical state of the engine and the maintenance records of the operator.
Findings
- The engine failure was caused by a fracture of the crankcase resulting from the breaking of a connecting rod.
- Specifically, the small end copper bushings of connecting rod No. 04 were found to be loose, rather than being installed with the required interference fit, leading to the failure of the rod and subsequent engine seizure.
- The engine had recently undergone an oil change and was part of a scheduled maintenance program.
- The pilot followed approved procedures for engine failure and performed the forced landing in an open field.
- The aircraft was not overloaded, and the weather conditions were calm with good visibility.
- The investigation noted that the operator's oil consumption records were not properly maintained and contained overwriting.