Date: 201408
Location: ZHU.ARTCC, TX
Flight conditions: VMC
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class A ZHU
ATC / advisory: Center ZHU
Aircraft component: FMS/FMC
Component problem: Design
Reporter organization: Air Carrier
Reporter function: First Officer
Human factors: Situational Awareness; Time Pressure; Training / Qualification; Workload; Human-Machine Interface; Communication Breakdown; Confusion; Distraction
Second reporter function: Captain
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Chart Or Publication; Human Factors; Procedure
Primary problem: Human Factors

Narrative: Houston Center issued a Descend Via clearance on the KIDDZ 1 Arrival but gave no runway transition assignment. When we asked [which runway to anticipate]; the Controller stated that he did not know which one they wanted downline. The routing changes with the specific runway transition. How do you fly this procedure with an incomplete/unclear clearance? This has happened several times coming in to HOU. We saw this same scenario going into DCA yesterday. On that arrival (FREEDOM) the altitudes are different depending on the transition. Again; Center assigned no transition when they issued the Descend Via clearance. We were told we would get it downline. How are we supposed to set up the FMS and fly that arrival? Our entire procedure of programming and verifying at altitude is undone. This is an unsafe practice; hence our FOM procedures. Please advise.ATC should only assign a Descend Via with the appropriate runway transition or they should modify the clearance to some different fix/altitude limit.

Callback: The reporter advised his company has established a special SOP for programming of RNAV STAR's which was the result of frequent 'incomplete' descend via clearances of the type addressed in his report; where there is no obvious bottom altitude on the STAR itself but are valid ones contained within subsequent runway based routings. Flight crews are now required; prior to start of descent; to obtain the ATIS from the destination airport and to program the FMS to include that routing from the last fix on the STAR to the ATIS runway. In addition...since they have not yet been cleared via that route...they are to leave in place--and/or manually insert--a route discontinuity between the last fix of the STAR and 'whatever it is they call' [the reporter's words] the charted routes between the last fix of the arrival and the landing runways/approaches.He further embellished his final comment to state that no 'descend via' should be issued by ATC that doesn't include a part of the total route which includes the required bottom altitude. If ATC is unable to do so for any reason the descend via clearance should include the language 'except maintain (an appropriate altitude).' This type of clearance is already an approved option for ATC in the FAA's extensive expansion of the meaning of descend via clearances and would; thus; allow flight crews to properly program and execute the clearance without the questionable practice of air carrier bulletin directives to program things into the FMS for which flight crews are not actually cleared.

Second narrative: ...The branch point altitude is 9;000 FT but the limit altitude [contained in the routing provided by programming the runway] is 6;000 FT. When queried as to the transition to fly; the Controller was flustered and stated they didn't give him that information and suggested we descend in accordance with the ATIS information......Additionally; sometimes follow-on hard altitudes past transition points make early clearance for both landing direction and often specific approach clearance imperative as soon as possible....


Synopsis: A B737-700 flight crew submitted a report echoing a number of others addressing the failure of ATC to provide the necessary information to conduct a descend via clearance when the necessary 'bottom altitude' for doing so exists only on the routing to the runway subsequent to the last 'common point' of the STAR itself.