I90 controller described a technical loss of separation event when an aircraft being vectored for a ...

Narrative:

Aircraft was being vectored for a visual approach to runway 27 but did not call the airport in sight prior to losing standard separation with another aircraft on an ILS approach to parallel runway 26L. There was reasonable assurance and expectation that the aircraft would call the airport in sight sooner; thus preventing a loss of separation; based previous aircraft actions. Safety was not compromised and no evasive actions were taken by either pilot as the aircraft flew the same route he would have flown if he had been cleared for the visual approach prior to loosing separation. Weather was a factor as cloud conditions were rapidly changing. Recommendation; anytime you run a visual approach you run the risk of the pilot not calling the airport for whatever reason so I'm not so sure there's a correct answer to this question other than it sometimes happens and is more circumstantial than factual.

Original NASA ASRS Text

Title: I90 Controller described a technical loss of separation event when an aircraft being vectored for a visual approach to Runway 27 at IAH failed to see the airport and lost separation with traffic inbound to Runway 26L; weather was listed a causal factor.

Narrative: Aircraft was being vectored for a visual approach to Runway 27 but did not call the airport in sight prior to losing standard separation with another aircraft on an ILS approach to parallel Runway 26L. There was reasonable assurance and expectation that the aircraft would call the airport in sight sooner; thus preventing a loss of separation; based previous aircraft actions. Safety was not compromised and no evasive actions were taken by either pilot as the aircraft flew the same route he would have flown if he had been cleared for the visual approach prior to loosing separation. Weather was a factor as cloud conditions were rapidly changing. Recommendation; anytime you run a visual approach you run the risk of the pilot not calling the airport for whatever reason so I'm not so sure there's a correct answer to this question other than it sometimes happens and is more circumstantial than factual.

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	895873
Time
Date	201006
Local Time Of Day	1201-1800
Place
Locale Reference	I90.TRACON
State Reference	TX
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

I90 controller described a technical loss of separation event when an aircraft being vectored for a visual approach to runway 27 at iah failed to see the airport and lost separation with traffic inbound to runway 26L; weather was listed a causal factor.