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An air carrier MD83 on radar vectors to the final approach course is unable to communicate with the controller due to frequency congestion and crosses final. A TCASII RA is received on a DH8 making a straight-in visual approach resulting in a 200 ft climb. After crossing final approach course, the MD83 received approach clearance.
| Attributes | |
| ACN | 412925 |
| Time | |
| Date | 199809 |
| Day | Wed |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : sea |
| State Reference | WA |
| Altitude | msl bound lower : 3000 msl bound upper : 3000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : sea |
| Operator | common carrier : air carrier |
| Make Model Name | MD-83 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | descent : approach |
| Route In Use | arrival other enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Dash 8 Series Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach descent other |
| Route In Use | approach : visual arrival other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 220 flight time total : 13000 flight time type : 4800 |
| ASRS Report | 412925 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : flight engineer pilot : cfi |
| Experience | flight time last 90 days : 167 flight time total : 12000 flight time type : 2100 |
| ASRS Report | 413140 |
| Events | |
| Anomaly | conflict : airborne less severe other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : took evasive action |
| Miss Distance | horizontal : 6000 vertical : 200 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
We were on a left downwind on descent for seatac when the problem began. The approach controller on frequency 119.5 handed us to final approach on 133.65. It was a beautiful, clear evening, and we had seatac mall and the airport insight and anticipated the mall visual approach to runway 34L/right (the approach in progress). From the first call on 133.65, the controller was totally covered up -- nonstop chatter. We normally fly further south to commencement bay before being turned in or cleared for the mall visual. The controller turned us to a 070 degree heading down to 3000 ft MSL just prior to the mall, to fit us in his traffic flow. We were slowed to approximately 190 KIAS to make the 90 degree turn to final at approximately 7 DME from the airport. The controller was so busy that he failed to issue clearance for the mall visual or anything else. The frequency was so congested that I (first officer was flying) could not call to prompt him. A commuter dash 8 (air carrier Y) had been cleared for the mall visual to runway 34R when 15 DME south of seatac. We should have been cleared for visual runway 34L. The at or above altitude over the mall is 3000 ft -- exactly where air carrier Y (90 degrees to us coming from the south) and us were close to meeting. Over the mall, we got a TCASII RA which commanded a climb which we followed. Air carrier Y had us in sight. I was finally able to ask approach for a clearance. We were given runway 34R and air carrier Y runway 34L. We had already overshot runway 34R and climbed approximately 200 ft, but the first officer did an excellent job getting the aircraft in the slot and stabilized for landing. The short turn-in on base leg was unusual, but would have worked if we had been cleared the mall visual when given that 070 degree heading. Causes: controller workload, frequency congestion, non routine short turn-in taking him out of his normal timing and pacing.
Original NASA ASRS Text
Title: AN ACR MD83 ON RADAR VECTORS TO THE FINAL APCH COURSE IS UNABLE TO COMMUNICATE WITH THE CTLR DUE TO FREQ CONGESTION AND CROSSES FINAL. A TCASII RA IS RECEIVED ON A DH8 MAKING A STRAIGHT-IN VISUAL APCH RESULTING IN A 200 FT CLB. AFTER XING FINAL APCH COURSE, THE MD83 RECEIVED APCH CLRNC.
Narrative: WE WERE ON A L DOWNWIND ON DSCNT FOR SEATAC WHEN THE PROB BEGAN. THE APCH CTLR ON FREQ 119.5 HANDED US TO FINAL APCH ON 133.65. IT WAS A BEAUTIFUL, CLR EVENING, AND WE HAD SEATAC MALL AND THE ARPT INSIGHT AND ANTICIPATED THE MALL VISUAL APCH TO RWY 34L/R (THE APCH IN PROGRESS). FROM THE FIRST CALL ON 133.65, THE CTLR WAS TOTALLY COVERED UP -- NONSTOP CHATTER. WE NORMALLY FLY FURTHER S TO COMMENCEMENT BAY BEFORE BEING TURNED IN OR CLRED FOR THE MALL VISUAL. THE CTLR TURNED US TO A 070 DEG HDG DOWN TO 3000 FT MSL JUST PRIOR TO THE MALL, TO FIT US IN HIS TFC FLOW. WE WERE SLOWED TO APPROX 190 KIAS TO MAKE THE 90 DEG TURN TO FINAL AT APPROX 7 DME FROM THE ARPT. THE CTLR WAS SO BUSY THAT HE FAILED TO ISSUE CLRNC FOR THE MALL VISUAL OR ANYTHING ELSE. THE FREQ WAS SO CONGESTED THAT I (FO WAS FLYING) COULD NOT CALL TO PROMPT HIM. A COMMUTER DASH 8 (ACR Y) HAD BEEN CLRED FOR THE MALL VISUAL TO RWY 34R WHEN 15 DME S OF SEATAC. WE SHOULD HAVE BEEN CLRED FOR VISUAL RWY 34L. THE AT OR ABOVE ALT OVER THE MALL IS 3000 FT -- EXACTLY WHERE ACR Y (90 DEGS TO US COMING FROM THE S) AND US WERE CLOSE TO MEETING. OVER THE MALL, WE GOT A TCASII RA WHICH COMMANDED A CLB WHICH WE FOLLOWED. ACR Y HAD US IN SIGHT. I WAS FINALLY ABLE TO ASK APCH FOR A CLRNC. WE WERE GIVEN RWY 34R AND ACR Y RWY 34L. WE HAD ALREADY OVERSHOT RWY 34R AND CLBED APPROX 200 FT, BUT THE FO DID AN EXCELLENT JOB GETTING THE ACFT IN THE SLOT AND STABILIZED FOR LNDG. THE SHORT TURN-IN ON BASE LEG WAS UNUSUAL, BUT WOULD HAVE WORKED IF WE HAD BEEN CLRED THE MALL VISUAL WHEN GIVEN THAT 070 DEG HDG. CAUSES: CTLR WORKLOAD, FREQ CONGESTION, NON ROUTINE SHORT TURN-IN TAKING HIM OUT OF HIS NORMAL TIMING AND PACING.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.