B737-800
Flight Crew Air Transport Pilot (ATP)
Time Pressure; Situational Awareness; Communication Breakdown; Distraction; Human-Machine Interface; Workload
Other Unwanted Situation
Aircraft; Procedure; Human Factors; Chart Or Publication; Airspace Structure
No incident occurred; however; I'm requesting a review of the DCA TRUPS 1 RNAV STAR. The newly initiated RNAV arrival is not user friendly. On more than one occasion I have found it difficult for the FMS and VNAV to keep up with the numerous points of below and above crossing altitudes; In addition; it demands an excessive amount of focus on the arrival at the cost of other responsibilities. It is hard to calculate the foot/minute descent rates required to back up the computer when there are multiple thousand foot variables on both ends. On this last flight; although we were given 'descend via' just prior to our top of descent point; we were able to dial in the altitude and begin the descent [in a timely fashion]. Although the 25KT tail winds were programmed into the Descent Forecast page so that the FMS had all the information it needed to complete the arrival; the aircraft was just barely able to make the descent between JARHD and PJAAE. If we had been given any speed reduction for spacing we would not have been able to make the crossing altitude. My recommendation would be to rework the arrival with no more than one 'below and above' crossing; configure the descent path with tail winds considered and with the prospect of being given a speed reduction for spacing during the descent. In an old B727 that can sink like a rock it would be easier; but with the newer; more efficient wings that don't descend so well--and absolutely do not slow down and go down at the same time--this arrival's descent path needs to be reconstructed. It is a violation waiting to happen or at least an arrival that will have 'unable crossing restriction' calls more frequently; which is not what is desired on a 'descend via' arrival [intended to reduce the flight crew's workload].
A B737NG Captain expressed concerns regarding the ability of aircraft to consistently comply with the altitude and airspeed restrictions on the TRUPS RNAV STAR to DCA. He deems the procedure to be too complex and so altitude/airspeed restrictive that compliance will frequently become impossible when tailwinds reduce the 'descent per NM' capability of modern aircraft.