Flight Crew Air Transport Pilot (ATP)
Time Pressure; Workload; Communication Breakdown; Human-Machine Interface; Distraction; Confusion
ATC Issue All Types
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure; Chart Or Publication
Enroute; we were issued an amended clearance to proceed to BUCKO; and then via the FRDMM1 RNAV arrival. This is a new procedure and this was the first time either of us had flown this arrival. The arrival is a very tedious affair. There are multiple limitations over nearly every fix on the arrival; to include minimum and maximum crossing altitudes; as well as varying speeds. This is a very high workload arrival; made more so by the fact that our FMS doesn't show the bracketed altitudes in the FMS; you have to scroll to the smallest scale on the DU; and verify on the DU that the brackets are correct. Additionally; we don't have the capability to program a bracket altitude into our FMS. We have to put in one side or the other. The arrival crossing restrictions were populated correctly; but this is a very high workload; heads down time to go through all the fixes and verify the FMS is accurate. Once we were established and descending via the arrival; we were handed off to Potomac Approach. The last 2 altitude crossing restrictions on the arrival are between 9;000 and 8;000 at FRDMM; then 6;000 at STAND for the Runway 19 transition. Shortly after checking in with Potomac; and while descending to meet the FRDMM restriction; ATC amended our clearance and issued after FRDMM; proceed direct to FERGI. This eliminated STAND from our flight plan; and its associated 6;000 FT crossing restriction. I asked ATC what altitude they wanted us to descend to; and they were completely confused; and commented we were just to continue descending via the arrival. I clarified the question; and they issued a clearance to 5;000 after FRDMM. This is a situation that leads to confusion. Additionally; the night before we were issued the TRUPS1 RNAV arrival into DCA; it is also a new arrival; and has the same transition from FRDMM to Runway 19. The exact same issue happened on that arrival; where they removed STAND; and its associated crossing altitude.
An MD80; cleared via the FRDMM RNAV STAR to DCA experienced excessive workload due to the complexity of the multiple airspeed and altitude restrictions required by the STAR. The workload was exacerbated by the inability of their FMS to both display and comply with the restrictions because it lacked the ability to program crossing altitude 'windows.' In addition; after having cleared them 'via' the arrival; Approach later cleared them direct to a waypoint beyond the waypoint whose altitude restriction constituted the flight's 'cleared' altitude. The Controller seemed unaware of their problem until precious comm time was taken to explain the fact they no longer had a cleared altitude.