Narrative:

2 pilots, both IFR. I was in right seat, talking to ATC. Other pilot flying. FAF was OM/NDB. ATC put us on ILS 5 mi out from FAF. OM was not received for unknown reason, but NDB indicated passage. Pilot started descent even though he thought he was outside FAF (OM/NDB). The approach is such that the MDA, MM and map are at the same point. When the MM was received the pilot said to start timing the approach and continued descending. I advised him that we were inside the MM. He believed so strongly that we were 1000' higher and 5 mi back that he asked me to call tower and tell them we had just passed the OM. I had to yell at him to look out the window and he was so startled that we were over the lights that he could not land the plane. I had to do so. His mental image of where we were on the approach was so strong that he ignored all the signs (altitude, NDB, MM, looking out window) that we were further in. From talking with him he said that his instrument had never stressed using every NAVAID and instrument while IFR. He would have crashed into the approach lights if I had not said anything.

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Original NASA ASRS Text

Title: LOW TIME INSTRUMENT PLT OF SMA BECAME DISORIENTED ON APCH TO AGC, DESCENDED BELOW MDA, WAS NOT LOOKING OUT. OBSERVER PLT IN COCKPIT LANDED THE ACFT.

Narrative: 2 PLTS, BOTH IFR. I WAS IN RIGHT SEAT, TALKING TO ATC. OTHER PLT FLYING. FAF WAS OM/NDB. ATC PUT US ON ILS 5 MI OUT FROM FAF. OM WAS NOT RECEIVED FOR UNKNOWN REASON, BUT NDB INDICATED PASSAGE. PLT STARTED DSCNT EVEN THOUGH HE THOUGHT HE WAS OUTSIDE FAF (OM/NDB). THE APCH IS SUCH THAT THE MDA, MM AND MAP ARE AT THE SAME POINT. WHEN THE MM WAS RECEIVED THE PLT SAID TO START TIMING THE APCH AND CONTINUED DSNDING. I ADVISED HIM THAT WE WERE INSIDE THE MM. HE BELIEVED SO STRONGLY THAT WE WERE 1000' HIGHER AND 5 MI BACK THAT HE ASKED ME TO CALL TWR AND TELL THEM WE HAD JUST PASSED THE OM. I HAD TO YELL AT HIM TO LOOK OUT THE WINDOW AND HE WAS SO STARTLED THAT WE WERE OVER THE LIGHTS THAT HE COULD NOT LAND THE PLANE. I HAD TO DO SO. HIS MENTAL IMAGE OF WHERE WE WERE ON THE APCH WAS SO STRONG THAT HE IGNORED ALL THE SIGNS (ALT, NDB, MM, LOOKING OUT WINDOW) THAT WE WERE FURTHER IN. FROM TALKING WITH HIM HE SAID THAT HIS INSTR HAD NEVER STRESSED USING EVERY NAVAID AND INSTRUMENT WHILE IFR. HE WOULD HAVE CRASHED INTO THE APCH LIGHTS IF I HAD NOT SAID ANYTHING.

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.