Date: 201411
Local time of day: 1801-2400
Location: IAD.Airport, DC
Flight conditions: VMC
Light: Night
Aircraft: Small Transport; Low Wing; 2 Turboprop Eng
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B IAD
ATC / advisory: TRACON PCT
Reporter organization: Corporate
Reporter function: Single Pilot; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Distraction; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: Flight was to IAD.  Original routing received from ATC was HVQ.GIBBZ2.  Approximately 100 NM West of HVQ; ATC advised that they would need to change our arrival and issued a new clearance which placed us on the DOCCS2 arrival.  Once we were established on the arrival (and now working with a different ATC facility) we were told to descend in accordance with the GIBBZ2.  I advised that we were not on the GIBBZ2; we had be reassigned to the DOCCS2.  Controller responded 'First I've heard of that; in that case proceed direct DOCCS; descend and maintain 9000 feet.'   A few minutes later (and now with a different controller) we were approaching the GIBBZ intersection (yes; GIBBZ is an intersection on the DOCCS arrival); the DOCCS2 arrival procedure indicated that we should expect to cross GIBBZ at 6000 feet.  As I had not yet received a clearance to that altitude I asked ATC 'Confirm that you want us to descend on the arrival to cross GIBBS at 6000 feet.'  Controller responded 'Affirmative' and I programmed the FMS-VNAV to cross GIBBZ at 6000 feet.  Approximately a minute later; the VNAV glide path had just centered and the aircraft was just pitching down to initiate the descent to 6000 feet (note that we were still West of GIBBZ at this point) when the controller came on frequency and told us to descend to 6000 feet.  This was quickly followed by a 20 degree turn and a request to increase descent rate.  Then I was asked if I had the other aircraft in sight (I did) and was told to maintain visual contact with him.  Later the controller came on the frequency and asked why I had not descended in accordance with the GIBBZ arrival and I advised (again) that we were not on the GIBBZ; we had be reassigned to the DOCCS arrival.   It was night and; although I had him in sight; I really don't have a good feel for how close we were to the other aircraft.  My TCAS never alerted either in the TA or the RA mode.  This event appears to be the result of a lack of communications between the different ATC facilities involved.  Once a revised clearance has been issued a system should be in place which clearly shows all controllers involved what the clearance is for that aircraft.  From my perspective; I'm happy to fly whatever arrival I'm assigned and accept revisions to the clearance as they become necessary; but once an arrival is changed everyone in the ATC system needs to have a clear understanding of what procedure has been assigned.




Synopsis: Pilot reports of receiving an amended clearance and having difficulties with other ATC facilities reference the clearance.