20 June 2007
Robinson Helicopters has issued a warning to R44 owners that they should fly their helicopters in trim. The company has, it says, received two R44 tail rotor blades with fatigue cracks at the leading edge in the most inboard white paint stripe (see figure alongside).
The cracked blades were from police helicopters, and the company suggests that these machines had frequently done orbits with nose-left yaw (using additional left pedal input). “Using left pedal to force the helicopter to fly out of trim can cause high fatigue stresses in the blades,” says Robinson. “TO PREVENT A CATASTROPHIC TAIL ROTOR BLADE FAILURE, AVOID FLYING OUT OF TRIM.”
In addition, it suggests that during each preflight you should inspect leading edges of tail rotor blades for cracks and wipe blades clean if necessary to make sure potential cracks are visible.
