DA40 Diamond Star
Air Traffic Control Fully Certified; Flight Crew Private
Flight Crew Last 90 Days 50; Flight Crew Total 600; Flight Crew Type 600
Aircraft Equipment Problem Less Severe
Flight Crew Became Reoriented
Weather; Aircraft
Diamond DA40 will suddenly get into a slip on its own without warning.  The apparent cause is that the nose wheel will suddenly turn left and lock against the stop in full left turn position (as if it were turning left on the ground); and it will put the aircraft into uncoordinated flight; and it is impossible to correct.  The autopilot will suddenly cause the plane to fly with left wing about two feet higher than the right wing; and the ball to move way off center to the right.  According to many posts on the Internet; I have found that many Diamond DA40s have this problem; and it is not correctable.  There is no adjustment on the plane or rudder trim to correct the problem.Flight in IFR or marginal VFR is worrisome when the ball is not centered; and the flight is not coordinated.  Main concern is that in cross checking instruments for reliability in IMC flight; the ball not being centered might lead one to become confused about possibility of instrument failure.  I contacted Diamond Aircraft in London; Ontario; Canada; and spoke to them about it.  They said they are aware of the problem; but management has decided not to address it to develop a solution.  There is no adjustment or rudder trim to correct the problem.  The problem also appears to slow the DA40 down by several knots.  The only known solution is to land the plane; and take off again; with hopes that the problem will not occur again; which is certainly not guaranteed.The problem is intermittent; and occurs without warning.  Our DA40 is a 2010; and it is my understanding from talking to a customer service rep for a Diamond dealer that the 2014 models also have the problem.  This is an unsafe condition for certain types of flight.
The reporter states that the nose wheel can turn to the left or right at takeoff or in cruise flight but does not always occur. Even when the nose wheel does not become cocked in flight there is a lot of vibration caused by the propeller slipstream impinging on the nose wheel fairing; which causes the wheel bearing retaining screws to loosen over time.
DA40 pilot experiences a yaw to the left in cruise requiring right rudder for coordinated flight. It is learned that this and many other DA40's have their nose wheels pivot to the right or left stop after lift off and cannot be recentered without landing.