|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||atc facility : dfw|
|Altitude||msl bound lower : 5000|
msl bound upper : 15000
|Controlling Facilities||artcc : zfw|
tracon : dfw
|Make Model Name||Any Unknown or Unlisted Aircraft Manufacturer|
|Flight Phase||climbout : intermediate altitude|
descent : approach
|Route In Use||arrival other|
|Affiliation||government : faa|
|Function||controller : approach|
|Qualification||controller : radar|
|Anomaly||non adherence : published procedure|
other anomaly other
other anomaly other
|Independent Detector||other controllera|
|Resolutory Action||none taken : anomaly accepted|
|Primary Problem||ATC Human Performance|
|Air Traffic Incident||Operational Deviation|
Inter Facility Coordination Failure
|ATC Facility||procedure or policy : unspecified|
On the 2 nights in question I was conducting out instruction on the feeder west sectors at dfw approach control. The feed on these 2 evenings from ZFW center degraded the traffic situation such that the sector was out of control and air safety was reduced to nothing more than luck. I believe the problem is created by the procedure incorporated into the letter of agreement between the 2 facs which allow ZFW to vector up to 15 mi inside the corner post VOR or 10 mi inside dfw. Airspace to achieve their spacing requirements. Traffic is arriving on a published (boids 9) STAR arrival. This arrival has crossing altitudes and crossing speeds. The practice allows ZFW controllers to proceed into TRACON airspace with vectors and speeds of their choice to 'hit the gap.' the preceding aircraft slowing to 250 KTS to meet the crossing speeds looms in front of the traffic still on center frequency flying at 380-420 KTS ground speed indicated. Closure is such that on numerous occasions altitude sep is applied by ZFW to ensure sep due to closure. This too often has placed the second aircraft in departure control airspace with no pointout (deviation). The vol of traffic is such that when 2-3 or 4 overtake situation occur either simultaneously or in rapid succession the complexity combined with vol over-saturates the sector. The procedure allows for a shotgun effect on traffic coming out of center airspace rather than a neat, organized flow. The flow into TRACON airspace is being achieved after entering the airspace and not before. Our sector was forced to stop accepting aircraft as we scrambled to survive yet the center continued to penetrate TRACON airspace with no handoff taken (deviation). These problems are a recurring thing. The procedures used were probably ok with the traffic vol such that it was yrs ago when written. However, today's traffic vol is too much for this procedure. The center should get their flow sequenced and orderly in their airspace free from the compression factor caused by speed reductions required on the arrival. Furthermore, they are free of surrounding airspace associated with the TRACON environment.
Original NASA ASRS Text
Title: ARRIVING ACFT PENETRATE FAC AIRSPACE IN ACCORDANCE WITH LETTER OF AGREEMENT AT VARIOUS SPEEDS AND ALTS RESULTING IN CONFLICTIONS WITH OTHER ACFT.
Narrative: ON THE 2 NIGHTS IN QUESTION I WAS CONDUCTING OUT INSTRUCTION ON THE FEEDER W SECTORS AT DFW APCH CTL. THE FEED ON THESE 2 EVENINGS FROM ZFW CENTER DEGRADED THE TFC SITUATION SUCH THAT THE SECTOR WAS OUT OF CTL AND AIR SAFETY WAS REDUCED TO NOTHING MORE THAN LUCK. I BELIEVE THE PROB IS CREATED BY THE PROC INCORPORATED INTO THE LETTER OF AGREEMENT BTWN THE 2 FACS WHICH ALLOW ZFW TO VECTOR UP TO 15 MI INSIDE THE CORNER POST VOR OR 10 MI INSIDE DFW. AIRSPACE TO ACHIEVE THEIR SPACING REQUIREMENTS. TFC IS ARRIVING ON A PUBLISHED (BOIDS 9) STAR ARR. THIS ARR HAS XING ALTS AND XING SPDS. THE PRACTICE ALLOWS ZFW CTLRS TO PROCEED INTO TRACON AIRSPACE WITH VECTORS AND SPDS OF THEIR CHOICE TO 'HIT THE GAP.' THE PRECEDING ACFT SLOWING TO 250 KTS TO MEET THE XING SPDS LOOMS IN FRONT OF THE TFC STILL ON CENTER FREQ FLYING AT 380-420 KTS GND SPD INDICATED. CLOSURE IS SUCH THAT ON NUMEROUS OCCASIONS ALT SEP IS APPLIED BY ZFW TO ENSURE SEP DUE TO CLOSURE. THIS TOO OFTEN HAS PLACED THE SECOND ACFT IN DEP CTL AIRSPACE WITH NO POINTOUT (DEVIATION). THE VOL OF TFC IS SUCH THAT WHEN 2-3 OR 4 OVERTAKE SITUATION OCCUR EITHER SIMULTANEOUSLY OR IN RAPID SUCCESSION THE COMPLEXITY COMBINED WITH VOL OVER-SATURATES THE SECTOR. THE PROC ALLOWS FOR A SHOTGUN EFFECT ON TFC COMING OUT OF CENTER AIRSPACE RATHER THAN A NEAT, ORGANIZED FLOW. THE FLOW INTO TRACON AIRSPACE IS BEING ACHIEVED AFTER ENTERING THE AIRSPACE AND NOT BEFORE. OUR SECTOR WAS FORCED TO STOP ACCEPTING ACFT AS WE SCRAMBLED TO SURVIVE YET THE CENTER CONTINUED TO PENETRATE TRACON AIRSPACE WITH NO HDOF TAKEN (DEVIATION). THESE PROBS ARE A RECURRING THING. THE PROCS USED WERE PROBABLY OK WITH THE TFC VOL SUCH THAT IT WAS YRS AGO WHEN WRITTEN. HOWEVER, TODAY'S TFC VOL IS TOO MUCH FOR THIS PROC. THE CENTER SHOULD GET THEIR FLOW SEQUENCED AND ORDERLY IN THEIR AIRSPACE FREE FROM THE COMPRESSION FACTOR CAUSED BY SPD REDUCTIONS REQUIRED ON THE ARR. FURTHERMORE, THEY ARE FREE OF SURROUNDING AIRSPACE ASSOCIATED WITH THE TRACON ENVIRONMENT.
Data retrieved from NASA's ASRS site as of August 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.