Narrative:

I was flying as first officer (PNF) on a flight from lch to iah after a reduced rest overnight in lch. WX was IFR for the flight and a normal takeoff and departure was made. En route conditions were VMC, however, houston, iah was IMC. I obtained the current ATIS at the time which was calling for indefinite ceilings 1/4 mi in fog and relayed to the captain the WX information. Included in our WX package was a NOTAM for iah runway 27 which stated that RVR 4000 ft is the minimums for the ILS due to a crane located in the vicinity of the new ATC tower. We decided that the ILS to runway 26 would be the best approach because RVR was reported to be greater than minimums. (I believe that they were calling for 1800 ft but it was up and down all morning). We were told to join the localizer for runway 26 and the captain established the aircraft on the localizer and GS at which point he asked if we were cleared for the approach. Approach control then cleared us for the ILS runway 26 approach, runway 26 RVR 1300 ft. We were still outside the marker and I was about to ask if this was ok. He then stated 'if you are wondering about this we are still good to go because we were established on the approach and the GS is the final approach fix and the RVR went below minimums after we were established on the GS.' within a few seconds later, the captain called for gear down, landing check. The landing checklist was accomplished and a normal landing was made. After landing, taxi, parking, and shutdown were all made without incident. After departing the aircraft, I queried the captain about the decision to continue the approach. He replied that in his last proficiency check that the same situation was simulated, and he was instructed that because he was established on the approach (regardless of distance implied) and had intercepted the GS that he was already beyond the final approach fix and could continue the approach. I do not believe that this is the case. The final approach fix on an ILS is the published GS intercept altitude on the approach plate. This is where the final approach segment is flown, you cannot begin to fly the final approach segment of an ILS unless the runway visibility are at or greater than published minimums. I think we got caught when we intercepted the GS above the published intercept altitude, and we were notified that the RVR was less than published minimums. A missed approach should have been executed at that point. Several factors contributed to the occurrence. First was a confusion on the regulations and procedures for an ILS approach. Second was my acceptance of the captain's explanation due in part to his status as a check airman, whom I thought knows everything. Third was the fatigue and stress caused by the reduced rest the night before, and concern for the airline company itself. I know that I should have persisted with my questioning of the approach, capts and check airman don't know it all. Lastly this whole mess could have been avoided if we had chosen the ILS to runway 27, because the NOTAM was not in effect!

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Original NASA ASRS Text

Title: LNDG MINIMUMS -- ACR CONTINUES APCH EVEN THOUGH THE FLC WAS ADVISED, PRIOR TO THE FAF, THAT THE VISIBILITY WAS BELOW MINIMUMS.

Narrative: I WAS FLYING AS FO (PNF) ON A FLT FROM LCH TO IAH AFTER A REDUCED REST OVERNIGHT IN LCH. WX WAS IFR FOR THE FLT AND A NORMAL TKOF AND DEP WAS MADE. ENRTE CONDITIONS WERE VMC, HOWEVER, HOUSTON, IAH WAS IMC. I OBTAINED THE CURRENT ATIS AT THE TIME WHICH WAS CALLING FOR INDEFINITE CEILINGS 1/4 MI IN FOG AND RELAYED TO THE CAPT THE WX INFO. INCLUDED IN OUR WX PACKAGE WAS A NOTAM FOR IAH RWY 27 WHICH STATED THAT RVR 4000 FT IS THE MINIMUMS FOR THE ILS DUE TO A CRANE LOCATED IN THE VICINITY OF THE NEW ATC TWR. WE DECIDED THAT THE ILS TO RWY 26 WOULD BE THE BEST APCH BECAUSE RVR WAS RPTED TO BE GREATER THAN MINIMUMS. (I BELIEVE THAT THEY WERE CALLING FOR 1800 FT BUT IT WAS UP AND DOWN ALL MORNING). WE WERE TOLD TO JOIN THE LOC FOR RWY 26 AND THE CAPT ESTABLISHED THE ACFT ON THE LOC AND GS AT WHICH POINT HE ASKED IF WE WERE CLRED FOR THE APCH. APCH CTL THEN CLRED US FOR THE ILS RWY 26 APCH, RWY 26 RVR 1300 FT. WE WERE STILL OUTSIDE THE MARKER AND I WAS ABOUT TO ASK IF THIS WAS OK. HE THEN STATED 'IF YOU ARE WONDERING ABOUT THIS WE ARE STILL GOOD TO GO BECAUSE WE WERE ESTABLISHED ON THE APCH AND THE GS IS THE FINAL APCH FIX AND THE RVR WENT BELOW MINIMUMS AFTER WE WERE ESTABLISHED ON THE GS.' WITHIN A FEW SECONDS LATER, THE CAPT CALLED FOR GEAR DOWN, LNDG CHK. THE LNDG CHKLIST WAS ACCOMPLISHED AND A NORMAL LNDG WAS MADE. AFTER LNDG, TAXI, PARKING, AND SHUTDOWN WERE ALL MADE WITHOUT INCIDENT. AFTER DEPARTING THE ACFT, I QUERIED THE CAPT ABOUT THE DECISION TO CONTINUE THE APCH. HE REPLIED THAT IN HIS LAST PROFICIENCY CHK THAT THE SAME SIT WAS SIMULATED, AND HE WAS INSTRUCTED THAT BECAUSE HE WAS ESTABLISHED ON THE APCH (REGARDLESS OF DISTANCE IMPLIED) AND HAD INTERCEPTED THE GS THAT HE WAS ALREADY BEYOND THE FINAL APCH FIX AND COULD CONTINUE THE APCH. I DO NOT BELIEVE THAT THIS IS THE CASE. THE FINAL APCH FIX ON AN ILS IS THE PUBLISHED GS INTERCEPT ALT ON THE APCH PLATE. THIS IS WHERE THE FINAL APCH SEGMENT IS FLOWN, YOU CANNOT BEGIN TO FLY THE FINAL APCH SEGMENT OF AN ILS UNLESS THE RWY VISIBILITY ARE AT OR GREATER THAN PUBLISHED MINIMUMS. I THINK WE GOT CAUGHT WHEN WE INTERCEPTED THE GS ABOVE THE PUBLISHED INTERCEPT ALT, AND WE WERE NOTIFIED THAT THE RVR WAS LESS THAN PUBLISHED MINIMUMS. A MISSED APCH SHOULD HAVE BEEN EXECUTED AT THAT POINT. SEVERAL FACTORS CONTRIBUTED TO THE OCCURRENCE. FIRST WAS A CONFUSION ON THE REGS AND PROCS FOR AN ILS APCH. SECOND WAS MY ACCEPTANCE OF THE CAPT'S EXPLANATION DUE IN PART TO HIS STATUS AS A CHK AIRMAN, WHOM I THOUGHT KNOWS EVERYTHING. THIRD WAS THE FATIGUE AND STRESS CAUSED BY THE REDUCED REST THE NIGHT BEFORE, AND CONCERN FOR THE AIRLINE COMPANY ITSELF. I KNOW THAT I SHOULD HAVE PERSISTED WITH MY QUESTIONING OF THE APCH, CAPTS AND CHK AIRMAN DON'T KNOW IT ALL. LASTLY THIS WHOLE MESS COULD HAVE BEEN AVOIDED IF WE HAD CHOSEN THE ILS TO RWY 27, BECAUSE THE NOTAM WAS NOT IN EFFECT!

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.