What happened
On 3 October 2019, a Cessna 152, registration G-BMXA, was conducting a training flight from Perth towards Edinburgh. Roughly 15 minutes after departing Perth, thick white smoke began flowing into the cockpit through the heating vents.
Upon noticing the smoke, the instructor assumed control of the aircraft and initiated engine fire emergency procedures. This included cutting the fuel mixture to idle cut-off and accelerating to maximum speed. However, after observing that no flames were present, the instructor re-advanced the mixture to fully rich to maintain engine power. A MAYDAY call was issued to Perth Radio, and the student pilot updated air traffic control using the 7700 emergency transponder code.
After identifying a suitable landing site, the instructor prepared the aircraft for a forced landing. At approximately 400 ft above ground level, the engine was shut down and full flaps were deployed. The aircraft landed successfully in a field of newly planted crops. The crew evacuated the aircraft and moved upwind with a fire extinguisher. There were no injuries to the two occupants, and the aircraft sustained no damage during the landing.
The investigation
Following the incident, an inspection of the aircraft was conducted. The crew observed oil streaking down the left side of the airframe and dripping from the engine cowling. A detailed examination of the engine components identified a crack in the engine crankcase.