A320
Communication Breakdown; Confusion
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance
Procedure; Chart Or Publication; Human Factors
RE the BULLZ RNAV STAR into ORD. If an aircraft is cleared to descend via the BULLZ arrival that aircraft will descend and reduce speed at specified points of the arrival. The BULLZ has aircraft cross TEDDY intersection at 11;000 feet at 250 knots.Both aircraft in this report were assigned 300 knots. Both aircraft were cleared direct TEDDY intersection. Both aircraft were issued a descent clearance to 15;000 feet. Both aircraft were then cleared to cross TEDDY at 11;000 feet. Both aircraft reduced speed to 250 knots at TEDDY without clearance to do so.I recommend speed restrictions be removed from the published BULLZ arrival. 70% of the time ORD is on a westerly flow and Approach Control requires the aircraft on the BULLZ arrival to cross TEDDY at 300 knots. This often causes confusion for the pilots and sometimes results in an aircraft not performing as directed or expected. Constantly having to restate or clarify clearances causes an increase in complexity and a decrease in safety and efficiency.
An ARTCC Controller expressed consternation at the failures of some flight crews to fail to maintain their assigned airspeed of 300 knots at TEDDY waypoint on the BULLZ RNAV STAR; instead slowing to 250 knots as published on the arrival.