What happened
On June 9, 2012, a professional pilot-instructor was conducting a flight in a new Cirrus SR22. Immediately after liftoff, the pilot detected a light, unusual vibration originating from the forward section of the aircraft. Unable to identify the source of the disturbance, the pilot elected to abort the takeoff and perform a landing on the remaining portion of the runway. The landing was completed safely without any threat to the crew or the aircraft.
After taxiing to the threshold of runway 28, the pilot performed a series of engine checks, including multiple applications of maximum power, which is not a standard part of the prescribed checklist. Following these tests, the engine appeared to be operating normally, and the pilot proceeded with a second takeoff attempt. This subsequent flight was completed without further incident.
The investigation
The investigation examined the aircraft's engine monitor records, which showed no deviations from normal operating parameters. Subsequent flights revealed that similar light vibrations occurred during several other takeoffs, though never during the established cruise phase of flight. To identify the source, the aircraft was subjected to additional inspections at a service station.
Findings
Technical inspections determined that the improper adjustment of the nose wheel bearing was the cause of the event. The bearing continued to rotate after takeoff, and depending on the rotation speed at the moment of liftoff, it transmitted vibrations through the airframe. The pilot's decision to abort the initial takeoff was determined to be correct.