Narrative:

WX at jnu was reported below approach minimums. The last special was -X 1/2 mi broken, calm winds. We held at asort. From our vantage point the WX was clear from the surface to the stars except for a patch of thick ground fog hovering over the airport vicinity. We could see the approach lighting system, especially the lead in lights, and some of the runway lights. We held at asort for approximately 45 mins until the WX was reported -5 mi broken, calm winds. We could see ground fog over the runway, so we briefed the possibility that we might not be able to land because of visibility restrs imposed by the ground fog. Prior to the missed approach point, the approach lighting system was in view, we configured for landing early to insure a stable approach once we descended below MDA. I turned off the inboard landing lights (leaving the outboard landing lights on). At the missed approach point, the VASI and runway lights began to appear. We decided to continue and proceeded through the 'cut' uneventfully. After passing the cut, I began calling sinks and speeds. The first officer delayed aligning the aircraft with the runway centerline until short final. Until this point we had unrestr horizontal visibility, the only restr being the fog over the runway. The closer we got, the more the runway lights revealed themselves. At approximately 50-75 ft we entered the fog. Slant range visibility began to diminish. Everything looked good until I realized the first officer wasn't going to flare. I call for the flare, however, it wasn't soon enough. We impacted the runway in a partial flare, right tire first, on centerline, approximately 1000 ft from the approach end. It was a hard landing, though, not the hardest in my career. The remainder of the landing and taxi in was uneventful other than the strong desire to relieve myself. I am surprised at how insidious the loss of depth perception was as we descended into the fog. Both of us didn't recognize the need to flare until it was too late. The brightness and high contrast of the runway lights immediately over the nose of the aircraft drew my attention away from the more distant lights, thus, my best cues for sensing sink and ht above the runway were compromised. This was also compounded by the first officer making final corrections to runway centerline. If I had to do it over again, I would have flown the approach in light of the first officer's experience, otherwise, I would have encourage the first officer to align and stabilize the aircraft much sooner on final and look down the runway instead of over the nose. Even if I had flown the approach, I'm not sure I would have started the flare in time either. If I had to do over again, I wouldn't do it again.

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Original NASA ASRS Text

Title: FO OF A B737-400 LOST DEPTH PERCEPTION DURING LNDG INTO FOG RESULTING IN A HARD LNDG. THERE WERE NO INJURIES OR KNOWN DAMAGE TO THE ACFT.

Narrative: WX AT JNU WAS RPTED BELOW APCH MINIMUMS. THE LAST SPECIAL WAS -X 1/2 MI BROKEN, CALM WINDS. WE HELD AT ASORT. FROM OUR VANTAGE POINT THE WX WAS CLR FROM THE SURFACE TO THE STARS EXCEPT FOR A PATCH OF THICK GND FOG HOVERING OVER THE ARPT VICINITY. WE COULD SEE THE APCH LIGHTING SYS, ESPECIALLY THE LEAD IN LIGHTS, AND SOME OF THE RWY LIGHTS. WE HELD AT ASORT FOR APPROX 45 MINS UNTIL THE WX WAS RPTED -5 MI BROKEN, CALM WINDS. WE COULD SEE GND FOG OVER THE RWY, SO WE BRIEFED THE POSSIBILITY THAT WE MIGHT NOT BE ABLE TO LAND BECAUSE OF VISIBILITY RESTRS IMPOSED BY THE GND FOG. PRIOR TO THE MISSED APCH POINT, THE APCH LIGHTING SYS WAS IN VIEW, WE CONFIGURED FOR LNDG EARLY TO INSURE A STABLE APCH ONCE WE DSNDED BELOW MDA. I TURNED OFF THE INBOARD LNDG LIGHTS (LEAVING THE OUTBOARD LNDG LIGHTS ON). AT THE MISSED APCH POINT, THE VASI AND RWY LIGHTS BEGAN TO APPEAR. WE DECIDED TO CONTINUE AND PROCEEDED THROUGH THE 'CUT' UNEVENTFULLY. AFTER PASSING THE CUT, I BEGAN CALLING SINKS AND SPDS. THE FO DELAYED ALIGNING THE ACFT WITH THE RWY CTRLINE UNTIL SHORT FINAL. UNTIL THIS POINT WE HAD UNRESTR HORIZ VISIBILITY, THE ONLY RESTR BEING THE FOG OVER THE RWY. THE CLOSER WE GOT, THE MORE THE RWY LIGHTS REVEALED THEMSELVES. AT APPROX 50-75 FT WE ENTERED THE FOG. SLANT RANGE VISIBILITY BEGAN TO DIMINISH. EVERYTHING LOOKED GOOD UNTIL I REALIZED THE FO WASN'T GOING TO FLARE. I CALL FOR THE FLARE, HOWEVER, IT WASN'T SOON ENOUGH. WE IMPACTED THE RWY IN A PARTIAL FLARE, R TIRE FIRST, ON CTRLINE, APPROX 1000 FT FROM THE APCH END. IT WAS A HARD LNDG, THOUGH, NOT THE HARDEST IN MY CAREER. THE REMAINDER OF THE LNDG AND TAXI IN WAS UNEVENTFUL OTHER THAN THE STRONG DESIRE TO RELIEVE MYSELF. I AM SURPRISED AT HOW INSIDIOUS THE LOSS OF DEPTH PERCEPTION WAS AS WE DSNDED INTO THE FOG. BOTH OF US DIDN'T RECOGNIZE THE NEED TO FLARE UNTIL IT WAS TOO LATE. THE BRIGHTNESS AND HIGH CONTRAST OF THE RWY LIGHTS IMMEDIATELY OVER THE NOSE OF THE ACFT DREW MY ATTN AWAY FROM THE MORE DISTANT LIGHTS, THUS, MY BEST CUES FOR SENSING SINK AND HT ABOVE THE RWY WERE COMPROMISED. THIS WAS ALSO COMPOUNDED BY THE FO MAKING FINAL CORRECTIONS TO RWY CTRLINE. IF I HAD TO DO IT OVER AGAIN, I WOULD HAVE FLOWN THE APCH IN LIGHT OF THE FO'S EXPERIENCE, OTHERWISE, I WOULD HAVE ENCOURAGE THE FO TO ALIGN AND STABILIZE THE ACFT MUCH SOONER ON FINAL AND LOOK DOWN THE RWY INSTEAD OF OVER THE NOSE. EVEN IF I HAD FLOWN THE APCH, I'M NOT SURE I WOULD HAVE STARTED THE FLARE IN TIME EITHER. IF I HAD TO DO OVER AGAIN, I WOULDN'T DO IT AGAIN.

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.