Narrative:

Medium large transport X inbound to alb visibility dropped to 1/2 mi while aircraft was well outside FAF. Approach controller made a broadcast to all aircraft that visibility was 1/2 (min for approach is 3/4), bjt did not get acknowledgements from any aircraft. Tower controller issued visibility of 1/2 mi on initial control. Aircraft at that point, was either at the FAF or about 1 mi outside of it. I was in the tower at the time and I thought the aircraft was about 1 mi from the FAF when the local controller issued the visibility. Pilot stated to me on the telephone that when he received the WX (1/2 mi visibility) he was 1/10 of a mi inside the FAF--so he continued the approach and additionally he was having a problem. His ILS receiver and that may have distracted him. #1 ATC error--no excuse for not getting acknowledgements from aircraft. If an acknowledgement is not received, you never gave the message. #2 pilot error--pilot was probably involved with navigation-aid receiver problem when approach control gave WX. When tower (local control) issued WX he was still concerned with his problem--as he stated to me. Additionally, he confirmed with the first officer that mins were 3/4. The question I have is why--when the visibility goes below mins, there is a problem with the ILS receiver and the aircraft is at such a critical point (FAF) with all these problems why continue the approach? Callback conversation with reporter revealed the following: reporter stated that after his telephone conversation with the pilot, he decided that a violation may not have occurred, so he did not forward a pilot deviation form to FSDO. Discussed the far covering this incident and agreed that if the pilot was on the final segment of his approach when he learned of the new visibility, he was legal to continue the approach. Reporter's concern involved the fact that the pilot continued an approach in worsening WX conditions, with an ILS receiver that was acting up. He feels that this showed bad judgement.

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Original NASA ASRS Text

Title: ATC SUPVR CONTENDS THAT FLT CREW USED BAD JUDGEMENT TO CONTINUE APCH AFTER VISIBILITY DROPPED BELOW MINS

Narrative: MLG X INBND TO ALB VISIBILITY DROPPED TO 1/2 MI WHILE ACFT WAS WELL OUTSIDE FAF. APCH CTLR MADE A BROADCAST TO ALL ACFT THAT VISIBILITY WAS 1/2 (MIN FOR APCH IS 3/4), BJT DID NOT GET ACKNOWLEDGEMENTS FROM ANY ACFT. TWR CTLR ISSUED VISIBILITY OF 1/2 MI ON INITIAL CTL. ACFT AT THAT POINT, WAS EITHER AT THE FAF OR ABOUT 1 MI OUTSIDE OF IT. I WAS IN THE TWR AT THE TIME AND I THOUGHT THE ACFT WAS ABOUT 1 MI FROM THE FAF WHEN THE LCL CTLR ISSUED THE VISIBILITY. PLT STATED TO ME ON THE TELEPHONE THAT WHEN HE RECEIVED THE WX (1/2 MI VISIBILITY) HE WAS 1/10 OF A MI INSIDE THE FAF--SO HE CONTINUED THE APCH AND ADDITIONALLY HE WAS HAVING A PROBLEM. HIS ILS RECEIVER AND THAT MAY HAVE DISTRACTED HIM. #1 ATC ERROR--NO EXCUSE FOR NOT GETTING ACKNOWLEDGEMENTS FROM ACFT. IF AN ACKNOWLEDGEMENT IS NOT RECEIVED, YOU NEVER GAVE THE MSG. #2 PLT ERROR--PLT WAS PROBABLY INVOLVED WITH NAV-AID RECEIVER PROBLEM WHEN APCH CTL GAVE WX. WHEN TWR (LC) ISSUED WX HE WAS STILL CONCERNED WITH HIS PROBLEM--AS HE STATED TO ME. ADDITIONALLY, HE CONFIRMED WITH THE F/O THAT MINS WERE 3/4. THE QUESTION I HAVE IS WHY--WHEN THE VISIBILITY GOES BELOW MINS, THERE IS A PROBLEM WITH THE ILS RECEIVER AND THE ACFT IS AT SUCH A CRITICAL POINT (FAF) WITH ALL THESE PROBLEMS WHY CONTINUE THE APCH? CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: RPTR STATED THAT AFTER HIS TELEPHONE CONVERSATION WITH THE PLT, HE DECIDED THAT A VIOLATION MAY NOT HAVE OCCURRED, SO HE DID NOT FORWARD A PLT DEVIATION FORM TO FSDO. DISCUSSED THE FAR COVERING THIS INCIDENT AND AGREED THAT IF THE PLT WAS ON THE FINAL SEGMENT OF HIS APCH WHEN HE LEARNED OF THE NEW VIS, HE WAS LEGAL TO CONTINUE THE APCH. RPTR'S CONCERN INVOLVED THE FACT THAT THE PLT CONTINUED AN APCH IN WORSENING WX CONDITIONS, WITH AN ILS RECEIVER THAT WAS ACTING UP. HE FEELS THAT THIS SHOWED BAD JUDGEMENT.

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.