Atx X had less than standard separation with aircraft Y on approach. System error.

Attributes
ACN	295412
Time
Date	199502
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : oak
State Reference	CA
Altitude	msl bound lower : 3400 msl bound upper : 3400
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air taxi
Make Model Name	Airliner 99
Operating Under FAR Part	Part 135
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 1840 flight time type : 90
ASRS Report	295412
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated faa : reviewed incident with flight crew
Miss Distance	horizontal : 12000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

X was on an IFR flight plan from mod to oak in be-99 as PIC. I was handed off to bay approach on vectors direct to oak from stockton approach, level at 6000 ft MSL. After checking in with bay approach, I was assigned a 230 degree vector to intercept the oak runway 27R localizer and descend to 3200 ft MSL. I read back this clearance and placed runway 29 ILS on request. Bay acknowledge my request by stating, 'I have your request.' at the appropriate time I turned to intercept the runway 27R localizer. I received a clearance from bay to turn left to 200 degrees immediately. At this point I was instructed to fly this vector then another vector of 260 degrees and 3000 ft MSL to intercept and fly the ILS 29 at oak. I understand that there was a lack of separation on the localizer for runway 27R. I was in IMC conditions at the time so cannot mention the proximity of the other aircraft. I was instructed to call the supervisor on duty at bay approach after landing. After review of the tapes, controller error was the concluding factor. The controller thought he had given me an amended clearance for runway 29 ILS at oak, which was not the case.

Original NASA ASRS Text

Title: ATX X HAD LTSS WITH ACFT Y ON APCH. SYS ERROR.

Narrative: X WAS ON AN IFR FLT PLAN FROM MOD TO OAK IN BE-99 AS PIC. I WAS HANDED OFF TO BAY APCH ON VECTORS DIRECT TO OAK FROM STOCKTON APCH, LEVEL AT 6000 FT MSL. AFTER CHKING IN WITH BAY APCH, I WAS ASSIGNED A 230 DEG VECTOR TO INTERCEPT THE OAK RWY 27R LOC AND DSND TO 3200 FT MSL. I READ BACK THIS CLRNC AND PLACED RWY 29 ILS ON REQUEST. BAY ACKNOWLEDGE MY REQUEST BY STATING, 'I HAVE YOUR REQUEST.' AT THE APPROPRIATE TIME I TURNED TO INTERCEPT THE RWY 27R LOC. I RECEIVED A CLRNC FROM BAY TO TURN L TO 200 DEGS IMMEDIATELY. AT THIS POINT I WAS INSTRUCTED TO FLY THIS VECTOR THEN ANOTHER VECTOR OF 260 DEGS AND 3000 FT MSL TO INTERCEPT AND FLY THE ILS 29 AT OAK. I UNDERSTAND THAT THERE WAS A LACK OF SEPARATION ON THE LOC FOR RWY 27R. I WAS IN IMC CONDITIONS AT THE TIME SO CANNOT MENTION THE PROX OF THE OTHER ACFT. I WAS INSTRUCTED TO CALL THE SUPVR ON DUTY AT BAY APCH AFTER LNDG. AFTER REVIEW OF THE TAPES, CTLR ERROR WAS THE CONCLUDING FACTOR. THE CTLR THOUGHT HE HAD GIVEN ME AN AMENDED CLRNC FOR RWY 29 ILS AT OAK, WHICH WAS NOT THE CASE.

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.