What happened
On 12 April 2004, a Diamond DA40D Diamond Star, registration G-CCHE, was performing a solo training circuit at Cranfield Airfield. During the climbout phase following a 'touch and go' maneuver, the aircraft reached approximately 400 feet while the engine began running unevenly. Air Traffic Control (ATC) observed smoke emitting from the aircraft and notified the pilot, though the pilot was cleared to continue the circuit as weather conditions were favorable.
Upon landing, the aircraft touched down to the right of the runway centerline. During the landing roll, the aircraft accelerated toward the right, exiting the runway and entering Taxiway C. The aircraft then veered left off the taxiway onto a grass area, where it eventually came to a halt. While the pilot escaped without injury, the left main landing gear sustained damage during the excursion.
The investigation
The investigation examined the engine performance and the pilot's actions during the landing roll. The pilot reported that an attempt to increase power during the climbout was unsuccessful. During the landing, the power lever remained partially open. The pilot noted that after touchdown, the aircraft appeared to accelerate, likely due to the power remaining above idle. Additionally, the pilot indicated that more pressure was applied to the right brake than the left while attempting to stop the aircraft.
Investigators also looked into the history of the engine's performance. It was noted that ATC had previously observed smoke from this specific aircraft during three separate climbouts. While previous instances of smoke and vibration had been addressed through engineering work following manufacturer advice, the smoke on this occasion persisted until after the aircraft had landed.
Findings
- The aircraft experienced engine instability and smoke emission during the climbout.
- The pilot maintained the power lever in a position greater than idle during the landing roll.
- Asymmetric braking, with higher pressure applied to the right brake, contributed to the aircraft's path.
- The engine's uneven running and smoke were part of a recurring, intermittent issue that had been previously observed on other flights.