Narrative:

The rails at dro were notamed OTS, but in referring to the nos approach plate for the ILS 2 approach at dro, there was no mention of higher minimums with the rails OTS, so when the visibility came up to 1/2 mi, we requested and were given approach clearance. After we were established on the localizer inbound, the pilot of another air carrier, who was holding behind us, called center and stated that he would need 3/4 mi for the approach with the RAIL OTS. My first officer and I briefly conferred and I quickly looked up the inoperative components table in the nos book. It mentioned that the minimums were 3/4 with the malsrs OTS, but said nothing about the rails. After our arrival, our station agent told me that the agents of 2 other air carrier's who had aircraft waiting for 3/4 mi to come in were wondering how we had been able to come in with 1/2 mi. In researching the situation after the fact, I found that on the charts the other air carrier's were using, it lists right on the face of the plate that minimums increase to 3/4 mi with ALS or rails OTS. What that tells me is that apparently if the rails are OTS, the malsrs are effectively out as well. Since we were established on the approach when the question came up, we didn't dig deeply enough to find that possibility.

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Original NASA ASRS Text

Title: FLT CREW OF LTT LANDED AT DRO BELOW WX MINIMUMS FOR MALSR (RAIL PORTION) OUT OF SERVICE.

Narrative: THE RAILS AT DRO WERE NOTAMED OTS, BUT IN REFERRING TO THE NOS APCH PLATE FOR THE ILS 2 APCH AT DRO, THERE WAS NO MENTION OF HIGHER MINIMUMS WITH THE RAILS OTS, SO WHEN THE VISIBILITY CAME UP TO 1/2 MI, WE REQUESTED AND WERE GIVEN APCH CLRNC. AFTER WE WERE ESTABLISHED ON THE LOC INBND, THE PLT OF ANOTHER ACR, WHO WAS HOLDING BEHIND US, CALLED CENTER AND STATED THAT HE WOULD NEED 3/4 MI FOR THE APCH WITH THE RAIL OTS. MY F/O AND I BRIEFLY CONFERRED AND I QUICKLY LOOKED UP THE INOP COMPONENTS TABLE IN THE NOS BOOK. IT MENTIONED THAT THE MINIMUMS WERE 3/4 WITH THE MALSRS OTS, BUT SAID NOTHING ABOUT THE RAILS. AFTER OUR ARR, OUR STATION AGENT TOLD ME THAT THE AGENTS OF 2 OTHER ACR'S WHO HAD ACFT WAITING FOR 3/4 MI TO COME IN WERE WONDERING HOW WE HAD BEEN ABLE TO COME IN WITH 1/2 MI. IN RESEARCHING THE SITUATION AFTER THE FACT, I FOUND THAT ON THE CHARTS THE OTHER ACR'S WERE USING, IT LISTS RIGHT ON THE FACE OF THE PLATE THAT MINIMUMS INCREASE TO 3/4 MI WITH ALS OR RAILS OTS. WHAT THAT TELLS ME IS THAT APPARENTLY IF THE RAILS ARE OTS, THE MALSRS ARE EFFECTIVELY OUT AS WELL. SINCE WE WERE ESTABLISHED ON THE APCH WHEN THE QUESTION CAME UP, WE DIDN'T DIG DEEPLY ENOUGH TO FIND THAT POSSIBILITY.

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.