|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : sts|
|Altitude||msl bound lower : 3000|
msl bound upper : 3000
|Controlling Facilities||artcc : zoa|
tower : sts
|Make Model Name||Experimental|
|Flight Phase||descent : approach|
landing : missed approach
|Route In Use||enroute : on vectors|
|Make Model Name||Small Aircraft, Low Wing, 2 Eng, Retractable Gear|
|Flight Phase||cruise other|
|Route In Use||departure sid : sid|
|Affiliation||government : faa|
|Function||controller : radar|
|Qualification||controller : radar|
|Affiliation||government : faa|
|Function||controller : flight data|
|Primary Problem||ATC Human Performance|
|Air Traffic Incident||Operational Error|
Inter Facility Coordination Failure
The incident occurred during a transfer of position responsibility. Aircraft were released off santa rosa airport with military spc X making practice approachs at santa rosa. 3-4 successive departures were released off sts with the minimum in trail sequencing. When I assumed control of the position spc X was on a vector for an ILS runway 32 approach to sts. I overhead (during the briefing) that 3 aircraft had been released off sts and discussion was carried on about X being on the approach. The d-side was also being relieved. After I turned spc X onto the sts localizer and cleared him for approach I inquired as to the status of the aircraft departing. With X on at a 7 mi final I was told to terminate his approach. I did so and issued a climb clearance to 4000' and a left 360 degree turn. I then identified the aircraft that had just departed sts and instructed him to maintain 3000'. We had 3.3 mi sep on the radar and 1000'. Once the radar sep was established and maintained I cleared the aircraft to their requested altitude and route of flight. From my understanding, sep was lost in the manual control environment. The sector was fairly saturated with holding aircraft, speed overtakes and sequencing into the sfo bay area. I don't believe radar sep was even lost. Supplemental information from acn 100257: I was relieving the d-ctlr at sector 40 and during my relief briefing I was told that spc X was requesting an ILS approach at sts estimating to arrive at XA40. Also I was told that small aircraft Y was released to depart sts via sts-south SID. Based on the information given to me aircraft were manually separated. However, the spc aircraft (arriving) was 7 mins early on the estimated time of arrival, therefore manual sep was lost. Supplemental information from acn 100474: the tower called and wanted 3 releases. I released the aircraft using a 3 min rule as I'd been taught to do. I informed the radar controller of what I had done, and which rule I'd used and the aircraft routes and altitudes. A supervisor was plugged in listening to me. The radar controller vectored military spc X out for a longer downwind. Sts called for another release which I released using the 3 min rule. I told the radar controller. About this time we were being relieved. All information was given to the new controllers and we left. The next day I was informed of the error. The 3 min rule only applies if the next aircraft is climbing higher than the first. All aircraft were the same altitude even though 2 aircraft courses diverged later. The second error occurred due to the military aircraft not being vectored out far enough to enable the fourth aircraft to depart at XA29.
Original NASA ASRS Text
Title: LESS THAN STANDARD SEPARATION BETWEEN 3 SMA DEPARTING STS ARPT, AND THEN LESS THAN STANDARD SEPARATION BETWEEN MIL-SPC AND SMA-TWIN.
Narrative: THE INCIDENT OCCURRED DURING A TRANSFER OF POS RESPONSIBILITY. ACFT WERE RELEASED OFF SANTA ROSA ARPT WITH MIL SPC X MAKING PRACTICE APCHS AT SANTA ROSA. 3-4 SUCCESSIVE DEPS WERE RELEASED OFF STS WITH THE MINIMUM IN TRAIL SEQUENCING. WHEN I ASSUMED CONTROL OF THE POS SPC X WAS ON A VECTOR FOR AN ILS RWY 32 APCH TO STS. I OVERHEAD (DURING THE BRIEFING) THAT 3 ACFT HAD BEEN RELEASED OFF STS AND DISCUSSION WAS CARRIED ON ABOUT X BEING ON THE APCH. THE D-SIDE WAS ALSO BEING RELIEVED. AFTER I TURNED SPC X ONTO THE STS LOC AND CLRED HIM FOR APCH I INQUIRED AS TO THE STATUS OF THE ACFT DEPARTING. WITH X ON AT A 7 MI FINAL I WAS TOLD TO TERMINATE HIS APCH. I DID SO AND ISSUED A CLB CLRNC TO 4000' AND A LEFT 360 DEG TURN. I THEN IDENTIFIED THE ACFT THAT HAD JUST DEPARTED STS AND INSTRUCTED HIM TO MAINTAIN 3000'. WE HAD 3.3 MI SEP ON THE RADAR AND 1000'. ONCE THE RADAR SEP WAS ESTABLISHED AND MAINTAINED I CLRED THE ACFT TO THEIR REQUESTED ALT AND ROUTE OF FLT. FROM MY UNDERSTANDING, SEP WAS LOST IN THE MANUAL CONTROL ENVIRONMENT. THE SECTOR WAS FAIRLY SATURATED WITH HOLDING ACFT, SPD OVERTAKES AND SEQUENCING INTO THE SFO BAY AREA. I DON'T BELIEVE RADAR SEP WAS EVEN LOST. SUPPLEMENTAL INFO FROM ACN 100257: I WAS RELIEVING THE D-CTLR AT SECTOR 40 AND DURING MY RELIEF BRIEFING I WAS TOLD THAT SPC X WAS REQUESTING AN ILS APCH AT STS ESTIMATING TO ARRIVE AT XA40. ALSO I WAS TOLD THAT SMA Y WAS RELEASED TO DEPART STS VIA STS-S SID. BASED ON THE INFO GIVEN TO ME ACFT WERE MANUALLY SEPARATED. HOWEVER, THE SPC ACFT (ARRIVING) WAS 7 MINS EARLY ON THE ESTIMATED TIME OF ARR, THEREFORE MANUAL SEP WAS LOST. SUPPLEMENTAL INFO FROM ACN 100474: THE TWR CALLED AND WANTED 3 RELEASES. I RELEASED THE ACFT USING A 3 MIN RULE AS I'D BEEN TAUGHT TO DO. I INFORMED THE RADAR CTLR OF WHAT I HAD DONE, AND WHICH RULE I'D USED AND THE ACFT ROUTES AND ALTS. A SUPVR WAS PLUGGED IN LISTENING TO ME. THE RADAR CTLR VECTORED MIL SPC X OUT FOR A LONGER DOWNWIND. STS CALLED FOR ANOTHER RELEASE WHICH I RELEASED USING THE 3 MIN RULE. I TOLD THE RADAR CTLR. ABOUT THIS TIME WE WERE BEING RELIEVED. ALL INFO WAS GIVEN TO THE NEW CTLRS AND WE LEFT. THE NEXT DAY I WAS INFORMED OF THE ERROR. THE 3 MIN RULE ONLY APPLIES IF THE NEXT ACFT IS CLBING HIGHER THAN THE FIRST. ALL ACFT WERE THE SAME ALT EVEN THOUGH 2 ACFT COURSES DIVERGED LATER. THE SECOND ERROR OCCURRED DUE TO THE MIL ACFT NOT BEING VECTORED OUT FAR ENOUGH TO ENABLE THE FOURTH ACFT TO DEPART AT XA29.
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.