EMB ERJ 145 ER/LR
Air Traffic Control Fully Certified
Confusion; Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Company Policy; Procedure; Aircraft
An E145 was cleared to descend via AARCH1 STAR. As often happens with E145's; CRJ2's and CRJ7's; the pilot was descending to the lowest available altitude on the transition; in this case the 12L/12R/11 transition. An A319 was about 10 MIT also descending via the AARCH1 and descending as the procedure was intended with a continuous descent. This put the A319 about 4;000 FT higher than the E145 at the intersections along the arrival near the T75/ZKC boundary. To try and maintain spacing; the E145 was assigned 300 KTS or more by ZKC and I advised the aircraft to delete the speed restrictions on the arrival. This is what typically occurs anytime E145's; CRJ2's; CRJ7's and similar aircraft fly the RNAV STARs and they are followed by B737's; A319's or other aircraft flying the procedures as intended. The E145's; CRJ2's; CRJ7's do not have adequate V-NAV so understandably they 'dive and drive;' creating overtakes with aircraft in trail. Because they are so much lower than aircraft behind them flying the procedure as designed; speed control is often not adequate and controllers have to take in trail aircraft off the descend via clearance on the RNAV STAR. This adds to workload; reduces efficiency and can lead to unsafe overtakes. I would recommend amending the STAR's to add new floor and ceiling altitudes at select intersections to reduce the altitude differential different aircraft are flying. Controllers and staff at ZKC and T75 are close to agreeing on what would work but the process is slowed considerably by funding concerns; lack of management backing and user concerns.
T75 Controller expressed concern regarding the descent profiles of the various aircraft based upon equipment; noting that those differences result in highly variable altitudes and speed differentials.