ARTCC controller had less than standard separation with widebody transport descending through altitu...

Attributes
ACN	86592
Time
Date	198804
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 27000 msl bound upper : 27300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa military facility : vbg
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 4 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : pacific enroute : other oceanic enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other cruise other
Route In Use	enroute other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	flight time last 90 days : 6 flight time total : 2
ASRS Report	86592
Person 2
Function	other personnel other
Qualification	controller : military
Events
Anomaly	airspace violation : exit conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 25200 vertical : 300
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Pilot Deviation Operational Error

Narrative:

Widebody transport X was inbound to sfo from over alcoa. Medium large transport Y was conducting a training test flight in the air carrier southwest farallon training area at FL270. Spc Z was operating in west 260 at FL310 B330. Widebody transport X was cleared to descend to FL280 from FL390 for arrival into sfo, and to keep separated with medium large transport Y. Widebody transport X route of flight took him about 8 mi from west 260. As widebody transport X neared west 260, spc Z began to spill out of the warning area. Widebody transport X was vectored away from west 260 and spc Z vandenberg frontier control advised that they were not in contact with spc Z, that the aircraft was having navigation problems, that spc Z would return to oak center frequencys. Attempts by oak center to contact spc Z, at that time, were not successful. It appeared the widebody transport X and spc Z would come into confliction. In order for widebody transport X to continue his descent at a good rate, he was cleared down to FL240. When widebody transport X left FL290, he was clear of spc Z, but as widebody transport X approached FL280 it was realized that he would come into confliction with medium large transport Y at FL270. Widebody transport X was instructed to maintain FL280. Widebody transport X acknowledged the clearance, but his rate of descent was such that he was unable to do so and was actually already below FL280. Medium large transport Y had been on an easterly heading and was instructed to turn left to a 340 degree heading. This was to take him behind widebody transport X. These actions were not timely enough to prevent a loss of sep. The closest the aircraft came to each other was 4.2 mi latitude and 300' vertical. The required sep was 5 mi latitude or 1000' vertical, neither of which was maintained. After these 2 aircraft diverged and sep was achieved, attempts at contacting spc Z were successful and we was advised that he had spilled out of west 260. Medium large transport Y was reclred to resume his own navigation in the training area. During the loss of sep, medium large transport Y and widebody transport X were both advised of their mutual traffic. Medium large transport Y reported the widebody transport X in sight.

Original NASA ASRS Text

Title: ARTCC CTLR HAD LESS THAN STANDARD SEPARATION WITH WDB DESCENDING THROUGH ALT OF MLG. SPC SPILLED OUT OF WARNING AREA CAUSING CTLR TO VECTOR THE WDB.

Narrative: WDB X WAS INBND TO SFO FROM OVER ALCOA. MLG Y WAS CONDUCTING A TRNING TEST FLT IN THE ACR SW FARALLON TRNING AREA AT FL270. SPC Z WAS OPERATING IN W 260 AT FL310 B330. WDB X WAS CLRED TO DSND TO FL280 FROM FL390 FOR ARR INTO SFO, AND TO KEEP SEPARATED WITH MLG Y. WDB X ROUTE OF FLT TOOK HIM ABOUT 8 MI FROM W 260. AS WDB X NEARED W 260, SPC Z BEGAN TO SPILL OUT OF THE WARNING AREA. WDB X WAS VECTORED AWAY FROM W 260 AND SPC Z VANDENBERG FRONTIER CTL ADVISED THAT THEY WERE NOT IN CONTACT WITH SPC Z, THAT THE ACFT WAS HAVING NAV PROBS, THAT SPC Z WOULD RETURN TO OAK CENTER FREQS. ATTEMPTS BY OAK CENTER TO CONTACT SPC Z, AT THAT TIME, WERE NOT SUCCESSFUL. IT APPEARED THE WDB X AND SPC Z WOULD COME INTO CONFLICTION. IN ORDER FOR WDB X TO CONTINUE HIS DSCNT AT A GOOD RATE, HE WAS CLRED DOWN TO FL240. WHEN WDB X LEFT FL290, HE WAS CLR OF SPC Z, BUT AS WDB X APCHED FL280 IT WAS REALIZED THAT HE WOULD COME INTO CONFLICTION WITH MLG Y AT FL270. WDB X WAS INSTRUCTED TO MAINTAIN FL280. WDB X ACKNOWLEDGED THE CLRNC, BUT HIS RATE OF DSCNT WAS SUCH THAT HE WAS UNABLE TO DO SO AND WAS ACTUALLY ALREADY BELOW FL280. MLG Y HAD BEEN ON AN EASTERLY HDG AND WAS INSTRUCTED TO TURN LEFT TO A 340 DEG HDG. THIS WAS TO TAKE HIM BEHIND WDB X. THESE ACTIONS WERE NOT TIMELY ENOUGH TO PREVENT A LOSS OF SEP. THE CLOSEST THE ACFT CAME TO EACH OTHER WAS 4.2 MI LAT AND 300' VERT. THE REQUIRED SEP WAS 5 MI LAT OR 1000' VERT, NEITHER OF WHICH WAS MAINTAINED. AFTER THESE 2 ACFT DIVERGED AND SEP WAS ACHIEVED, ATTEMPTS AT CONTACTING SPC Z WERE SUCCESSFUL AND WE WAS ADVISED THAT HE HAD SPILLED OUT OF W 260. MLG Y WAS RECLRED TO RESUME HIS OWN NAV IN THE TRNING AREA. DURING THE LOSS OF SEP, MLG Y AND WDB X WERE BOTH ADVISED OF THEIR MUTUAL TFC. MLG Y RPTED THE WDB X IN SIGHT.

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.

ARTCC controller had less than standard separation with widebody transport descending through altitude of medium large transport. Spc spilled out of warning area causing controller to vector the widebody transport.