Narrative:

Castle approach controller had issued heading 120 degrees and 3000' and to expect the ILS runway 28R approach. At approximately 7 mi from the airport on a left downwind the airport was in sight and was reported to ATC and a contact approach was requested. Castle reported traffic on final for runway 28R at modesto. At first we were unable to see the traffic and reported not in sight (the controller seemed to be confused or preoccupied on the term contact approach). The other aircraft was then sighted and reported in sight. I again requested the contact approach. Like before, another long pause from approach control and the captain began a left turn to final and I brought to his attention that we were turning off of our assigned heading and altitude as he began his des. The controller then said contact the tower. I contacted the tower and asked him to verify that we were clrd for the contact approach. After a long pause he clrd us for the contact approach and to land. In summation, there seemed to be some confusion on who was supposed to contact the tower between us and ATC. Castle seemed to be confused on the term or definition of a contact approach and my position as a non flying copilot trying to clarify ATC instructions and stop or bring to the attention of the captain that he is deviating from the last assigned clearance resulted in an unclr situation.

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Original NASA ASRS Text

Title: REPORTER STATES ATC CTLR DID NOT HANDLE REQUEST FOR CONTACT APCH. FLT CREW DEVIATED FROM ASSIGNED RADAR VECTOR HEADING.

Narrative: CASTLE APCH CTLR HAD ISSUED HDG 120 DEGS AND 3000' AND TO EXPECT THE ILS RWY 28R APCH. AT APPROX 7 MI FROM THE ARPT ON A LEFT DOWNWIND THE ARPT WAS IN SIGHT AND WAS RPTED TO ATC AND A CONTACT APCH WAS REQUESTED. CASTLE RPTED TFC ON FINAL FOR RWY 28R AT MODESTO. AT FIRST WE WERE UNABLE TO SEE THE TFC AND RPTED NOT IN SIGHT (THE CTLR SEEMED TO BE CONFUSED OR PREOCCUPIED ON THE TERM CONTACT APCH). THE OTHER ACFT WAS THEN SIGHTED AND RPTED IN SIGHT. I AGAIN REQUESTED THE CONTACT APCH. LIKE BEFORE, ANOTHER LONG PAUSE FROM APCH CTL AND THE CAPT BEGAN A LEFT TURN TO FINAL AND I BROUGHT TO HIS ATTN THAT WE WERE TURNING OFF OF OUR ASSIGNED HDG AND ALT AS HE BEGAN HIS DES. THE CTLR THEN SAID CONTACT THE TWR. I CONTACTED THE TWR AND ASKED HIM TO VERIFY THAT WE WERE CLRD FOR THE CONTACT APCH. AFTER A LONG PAUSE HE CLRD US FOR THE CONTACT APCH AND TO LAND. IN SUMMATION, THERE SEEMED TO BE SOME CONFUSION ON WHO WAS SUPPOSED TO CONTACT THE TWR BTWN US AND ATC. CASTLE SEEMED TO BE CONFUSED ON THE TERM OR DEFINITION OF A CONTACT APCH AND MY POSITION AS A NON FLYING COPLT TRYING TO CLARIFY ATC INSTRUCTIONS AND STOP OR BRING TO THE ATTN OF THE CAPT THAT HE IS DEVIATING FROM THE LAST ASSIGNED CLRNC RESULTED IN AN UNCLR SITUATION.

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.