Date: 201303
Local time of day: 0601-1200
Location: S46.TRACON, WA
Flight conditions: IMC
Light: Daylight
Aircraft: Medium Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent; Initial Approach
Airspace: Class E S46
ATC / advisory: TRACON S46
Aircraft component: FMS/FMC
Component problem: Design; Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Distraction; Workload
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Aircraft; Chart Or Publication; Procedure
Primary problem: Procedure

Narrative: During arrival on the HAWKZ TWO with north flow in SEA; we were initially assigned Runway 34C while descending through approximately 12;000 FT. The crossing altitude for FOOTT intersection on the arrival has charted between 12;000 FT and 10;000 FT. The Captain had trouble re-establishing his VPATH so we crossed FOOTT intersection on the arrival 700 FT high. We proceeded across GOALZ at the back calculated altitude in the FMS. At this point we switched to heading and vertical speed modes in order to cross fill the approach for 34C as the approach for 34L had been preloaded. As expected this dumped the back calculated altitude and we were left with no vertical guidance except the altitude alerter. About 3 NM from SONDR we reported the airport and the Commons Mall in sight but were cleared for the ILS to 34C via the transition to LORIE. Since the transition from CIDUG had been loaded in anticipation of a visual approach; the approach once again had to be modified in the FMS. At this point we crossed SONDR at airspeed of approximately 225 KTS instead of the published 210 KT speed restriction. The Controller then asked us to reduce speed to 210 KTS. Upon intercepting the final approach course to 34C we were assigned a speed of 160 KTS and then subsequently the Controller changed our runway assignment to 34L. We then were asked if we had company traffic in sight which we did not. The Controller then canceled our approach clearance; turned us out to the west; and climbed us to 4;000 FT to attempt the approach again. I believe this event can partially be attributed to pre-planning and pre-programming the FMS in anticipation of a visual approach after SONDR. The cause of this event can also be attributed to the high workload created by numerous altitude and airspeed gates that must be achieved on the HAWKZ TWO arrival coupled with SEA TRACON's uncertainty on runway assignments. The nature of this arrival creates a programming nightmare below 10;000 FT primarily when the expected approach and runway assignment aren't given until late in the arrival.




Synopsis: SEA TRACON canceled an air carrier approach to Runway 34L on the HAWKZ TWO RNAV because they did not see traffic ahead but the Captain was still attempting to reprogram his FMS after ATC changed the landing runway from 34C to 34L.