Narrative:

I was acting as first officer on flight from den to iah. We were flying the struk 7 arrival and then received radar vectors for the ILS 4 approach. The captain was the PF. Initial interception of the ILS course was normal; however, flight visibility seemed much less than the 8 mi broadcast on ATIS. Seemed about 2-3 mi. At approximately 1000' AGL, we saw the runway and realized we were much too high to land safely. We asked the tower if they had us in sight, as we were concerned it might be the wrong runway. They did have us in sight and agreed a go around was in order. Both ILS receivers were tuned and idented to the ILS 4 at hou, and showed us on localizer and G/south. As we started the mis, my G/south pointed showed a fly up indication and the captain's abruptly went to a full scale fly down indication. We now received vectors for another ILS 4 approach; however, our vector to final was so bad that the localizer was still full scale right as the G/south pointed on both receivers came through center and started down. At about this point we saw the runway, turned in and made a normal landing. If we had not seen the runway, we would have had to miss the approach again. On the ground at iah, the captain and I discussed this whole situation at length. We wondered if we were given an incorrect intercept altitude and thus had a 'false G/south,' or if maybe an aircraft had taxied in front of the G/south ant, to which iah tower replied no. After all the confusion of the missed approach and second ILS approach to 4, neither the captain nor I could remember what intercept altitude the approach controller gave us on the first ILS 4 approach.as we went to the hotel that night, we still did not know why we ended up too high on the first approach. Both G/south receivers showed on course up to the point that we saw the runway and realized we were too high. Runway 4 at iah has no VASI lights. Per company SOP, we had also performed the 'ILS test' on both navigation receivers during our initial setup in den.

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Original NASA ASRS Text

Title: ACR MLG HAD TO MAKE A GO AROUND WHEN FLT CREW SAW THEY WERE TOO HIGH AS THE RWY WAS SIGHTED FOLLOWING A NIGHT ILS APCH TO IAH.

Narrative: I WAS ACTING AS F/O ON FLT FROM DEN TO IAH. WE WERE FLYING THE STRUK 7 ARR AND THEN RECEIVED RADAR VECTORS FOR THE ILS 4 APCH. THE CAPT WAS THE PF. INITIAL INTERCEPTION OF THE ILS COURSE WAS NORMAL; HOWEVER, FLT VISIBILITY SEEMED MUCH LESS THAN THE 8 MI BROADCAST ON ATIS. SEEMED ABOUT 2-3 MI. AT APPROX 1000' AGL, WE SAW THE RWY AND REALIZED WE WERE MUCH TOO HIGH TO LAND SAFELY. WE ASKED THE TWR IF THEY HAD US IN SIGHT, AS WE WERE CONCERNED IT MIGHT BE THE WRONG RWY. THEY DID HAVE US IN SIGHT AND AGREED A GAR WAS IN ORDER. BOTH ILS RECEIVERS WERE TUNED AND IDENTED TO THE ILS 4 AT HOU, AND SHOWED US ON LOC AND G/S. AS WE STARTED THE MIS, MY G/S POINTED SHOWED A FLY UP INDICATION AND THE CAPT'S ABRUPTLY WENT TO A FULL SCALE FLY DOWN INDICATION. WE NOW RECEIVED VECTORS FOR ANOTHER ILS 4 APCH; HOWEVER, OUR VECTOR TO FINAL WAS SO BAD THAT THE LOC WAS STILL FULL SCALE RIGHT AS THE G/S POINTED ON BOTH RECEIVERS CAME THROUGH CENTER AND STARTED DOWN. AT ABOUT THIS POINT WE SAW THE RWY, TURNED IN AND MADE A NORMAL LNDG. IF WE HAD NOT SEEN THE RWY, WE WOULD HAVE HAD TO MISS THE APCH AGAIN. ON THE GND AT IAH, THE CAPT AND I DISCUSSED THIS WHOLE SITUATION AT LENGTH. WE WONDERED IF WE WERE GIVEN AN INCORRECT INTERCEPT ALT AND THUS HAD A 'FALSE G/S,' OR IF MAYBE AN ACFT HAD TAXIED IN FRONT OF THE G/S ANT, TO WHICH IAH TWR REPLIED NO. AFTER ALL THE CONFUSION OF THE MISSED APCH AND SECOND ILS APCH TO 4, NEITHER THE CAPT NOR I COULD REMEMBER WHAT INTERCEPT ALT THE APCH CTLR GAVE US ON THE FIRST ILS 4 APCH.AS WE WENT TO THE HOTEL THAT NIGHT, WE STILL DID NOT KNOW WHY WE ENDED UP TOO HIGH ON THE FIRST APCH. BOTH G/S RECEIVERS SHOWED ON COURSE UP TO THE POINT THAT WE SAW THE RWY AND REALIZED WE WERE TOO HIGH. RWY 4 AT IAH HAS NO VASI LIGHTS. PER COMPANY SOP, WE HAD ALSO PERFORMED THE 'ILS TEST' ON BOTH NAV RECEIVERS DURING OUR INITIAL SETUP IN DEN.

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.