An unclr vector heading given by TRACON causes a track deviation near sea, wa.

Attributes
ACN	494240
Time
Date	200012
Day	Tue
Local Time Of Day	0601 To 1200
Place
State Reference	WA
Altitude	msl bound lower : 7000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : s46.tracon tower : lax.tower
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : intermediate altitude
Route In Use	arrival : on vectors arrival star : glasr.3
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	494240
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
ASRS Report	494239
Events
Anomaly	non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance controller : issued advisory
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

On glasr 3 arrival to sea for a VFR approach to runway 34L, established on course to hethr intersection, we were given a clearance by approach control to depart hethr on a heading of 165 degrees (versus published 160 degree heading). Clearance was acknowledged. Several mi prior to hethr a subsequent clearance was issued to turn to a 165 degree heading. This clearance was also acknowledged and a turn to 165 degree heading was made. After established on 165N degree heading, approach control asked if we were aware that the 165 degree heading was supposed to be initiated at hethr, to which we responded that we understood we were reclred to turn prior to hethr. We were informed that was not the intention and were given instructions to turn right to intercept the sea 020 degree radial to hethr. Once established over hethr, the clearance to turn to 165 degree heading was reissued and complied with.

Original NASA ASRS Text

Title: AN UNCLR VECTOR HDG GIVEN BY TRACON CAUSES A TRACK DEV NEAR SEA, WA.

Narrative: ON GLASR 3 ARR TO SEA FOR A VFR APCH TO RWY 34L, ESTABLISHED ON COURSE TO HETHR INTXN, WE WERE GIVEN A CLRNC BY APCH CTL TO DEPART HETHR ON A HDG OF 165 DEGS (VERSUS PUBLISHED 160 DEG HDG). CLRNC WAS ACKNOWLEDGED. SEVERAL MI PRIOR TO HETHR A SUBSEQUENT CLRNC WAS ISSUED TO TURN TO A 165 DEG HDG. THIS CLRNC WAS ALSO ACKNOWLEDGED AND A TURN TO 165 DEG HDG WAS MADE. AFTER ESTABLISHED ON 165N DEG HDG, APCH CTL ASKED IF WE WERE AWARE THAT THE 165 DEG HDG WAS SUPPOSED TO BE INITIATED AT HETHR, TO WHICH WE RESPONDED THAT WE UNDERSTOOD WE WERE RECLRED TO TURN PRIOR TO HETHR. WE WERE INFORMED THAT WAS NOT THE INTENTION AND WERE GIVEN INSTRUCTIONS TO TURN R TO INTERCEPT THE SEA 020 DEG RADIAL TO HETHR. ONCE ESTABLISHED OVER HETHR, THE CLRNC TO TURN TO 165 DEG HDG WAS REISSUED AND COMPLIED WITH.

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.