Operations of the latest version of Eurocopter’s ubiquitous light single, the AS350B3e Ecureuil/AStar, have been affected by an emergency service bulletin and accompanying emergency Airworthiness Directive (AD).

Under the restrictions, the helicopter’s true airspeed is limited to 100 knots to reduce dynamic loads on the tail rotor. In addition, repetitive inspections must be conducted, with maximum intervals of three flight hours, on the laminated half-bearings.

As a result, “The business case for those services that we provide for a flat rate is degraded,” one mountainous-area AStar operator told AIN. At 10,000 feet, the Vne has been reduced from 125 knots to 86 knots. A source close to other operators emphasized the three-hour-interval check has limited the B3e’s radius of action.

The emergency AD was prompted by the fatal crash of a B3e in Guatemala in late September. There is strong suspicion that deterioration of the half-bearings led to failure of the tail rotor. Eurocopter has also devised a procedure to assist the pilot in the event of in-flight vibration being felt in the pedals.