TRACON controller described a loss of separation between an IFR aircraft cleared for a visual approa...

Narrative:

A king air was set up for a right traffic downwind into the airport. I cleared the pilot for the visual approach to runway 28R. The pilot continued eastbound to adjust the altitude/position in relationship to the airport. Instead of making a right base he did a left 270 to base. This maneuver took the aircraft back towards the neighboring airports final approach course (the other airport is only 4 miles north of the king air's destination airport). As soon as I noticed this maneuver; I instructed the pilot to immediately turn south for traffic. A F18 was on visual approach to the other airport and was already talking to that airport's tower. The pilot's unexpected left turn to final resulted in a loss of standard IFR separation; after reviewing the event the reported closest proximity of 2.79 miles. I initially reported the event to management because I thought it was surely a pilot deviation. I was advised that the pilot is authorized to turn away from the airport on a visual approach. I don't know if they are correct. Every controller I presented this situation to have had the same response; we all believe that the pilot was in error. At minimum it shows a lack of common sense on the pilot's part. I recommend a change to aim and or 7110.65 to show 'pilots on right traffic visual approaches shall make right turns and pilots on left traffic visual approaches shall make left turns.'

Original NASA ASRS Text

Title: TRACON Controller described a loss of separation between an IFR aircraft cleared for a Visual Approach and IFR traffic inbound to an adjacent airport when the Visual Approach aircraft made an unexpected turn to loose altitude.

Narrative: A King Air was set up for a right traffic downwind into the airport. I cleared the pilot for the Visual Approach to Runway 28R. The pilot continued eastbound to adjust the altitude/position in relationship to the airport. Instead of making a right base he did a left 270 to base. This maneuver took the aircraft back towards the neighboring airports final approach course (the other airport is only 4 miles north of the King Air's destination airport). As soon as I noticed this maneuver; I instructed the pilot to immediately turn south for traffic. A F18 was on Visual Approach to the other airport and was already talking to that airport's Tower. The pilot's unexpected left turn to final resulted in a loss of standard IFR separation; after reviewing the event the reported closest proximity of 2.79 miles. I initially reported the event to management because I thought it was surely a pilot deviation. I was advised that the pilot is authorized to turn AWAY from the airport on a Visual Approach. I don't know if they are correct. Every Controller I presented this situation to have had the same response; we all believe that the pilot was in error. At minimum it shows a lack of common sense on the pilot's part. I recommend a change to AIM and or 7110.65 to show 'Pilots on right traffic Visual Approaches shall make right turns and pilots on left traffic Visual Approaches shall make left turns.'

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	983103
Time
Date	201112
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Super King Air 200
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Hornet (F-18)
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Departure Approach
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

TRACON controller described a loss of separation between an IFR aircraft cleared for a visual approach and IFR traffic inbound to an adjacent airport when the visual approach aircraft made an unexpected turn to loose altitude.