Narrative:

This leg started in narita, japan and was scheduled to land on saipan island. The flight started off routinely. I did, however, notice that it was difficult to trim up the aircraft while climbing out, especially laterally. With my lack of experience on this aircraft type, I determined it was an idiosyncrasy of this airplane in particular. Nothing out of the ordinary occurred en route. Approaching saipan, we received the WX over voice and via ACARS. We knew there would be rain showers over the area, ragged ceilings, and gusty winds. In briefing the approach, discussion included selecting minimum brakes due to a possibly wet runway. The captain voiced the opinion that at our gross weight, about 580000 pounds, we did not want a problem landing long on the 7500 ft runway. Previous experience into saipan had shown that with an early descent, oftentimes one could visually obtain the runway early enough so as to preclude lengthy vectoring. That was the plan until we were informed that we were #3 for approach and landing, to slow up some 100 mi from the field, and that there were rain showers on final, so we were to expect the ILS to runway 7. We were given delaying vectors, and some 30 mi from the field, we were finally given a heading to intercept the localizer. At 5000 ft MSL on final approach, we decided to follow the GS down. Once on final, having slowed to maneuvering airspeed with flaps out at 10 degrees, then 20 degrees with gear down, then 25 degrees, I noticed it was taking much effort to control aircraft heading within +/-15 degrees either side of course. This was in my mind a little excessive for the wind conditions, which were pretty much a straight headwind. Pitch control also seemed slightly heavy. Despite all of that, the other crew members noted that I had the approach 'wired' (little did they realize how much effort I was putting into controling the aircraft to make it seem that way). We broke out about 1 1/2 mi out once we got below the ragged ceiling, about 500-600 ft MSL. I kept peering periodically at my flight instruments while transitioning to a visual approach, until I knew we were clear of all obscurations. The captain announced on short final (100-200 ft AGL) that my airspeed was about vref, so I added a little power, keeping the gusty winds in mind. I heard the 100 ft voice command flare tone, and I kept the descent going. The 30 ft voice command flare tone went off, and I started flaring. The 20 ft voice command flare tone then went off, and I pulled back more. It did not feel like I could pull the nose up any more, it felt as if something was pushing down on the aircraft. We never received a sink rate or any other kind of warning throughout the approach and landing. The aircraft touched down straight ahead with an incomplete flare, almost like stuffing a shoe or stubbing a toe. No crab was felt, and we taxied the aircraft to the gate performing the normal flow patterns and checklists without incident. The landing had been firm, but we all agreed we had been privy to much firmer, harder lndgs. No panels or oxygen masks had fallen down. On the so's subsequent preflight 1 1/2 hours later, he discovered the left inboard flap canoe seemed to have come dislodged, the flap had impinged the left aileron, and a flap rod assembly had broken off its bracket. Whether this maintenance problem had occurred while bringing the flaps up, either on climb out or after landing, or while being deployed, is anyone's guess right now. As far as the landing was concerned, it may have occurred in part by the flap problem, a downdraft, or a loss of gust. Other contributing factors included the voice command flare tones, lack of crew experience (the captain had just over 100 hours time in command of the B747, I have just over 250 hours and 25 lndgs in the B747) and chronic fatigue (this was day 13 out of 14 on the road for me).

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Original NASA ASRS Text

Title: A B747 CREW SURMISE A FIRM LNDG AT SAIPAN (PGSN) WAS DUE TO A FLAP PROB.

Narrative: THIS LEG STARTED IN NARITA, JAPAN AND WAS SCHEDULED TO LAND ON SAIPAN ISLAND. THE FLT STARTED OFF ROUTINELY. I DID, HOWEVER, NOTICE THAT IT WAS DIFFICULT TO TRIM UP THE ACFT WHILE CLBING OUT, ESPECIALLY LATERALLY. WITH MY LACK OF EXPERIENCE ON THIS ACFT TYPE, I DETERMINED IT WAS AN IDIOSYNCRASY OF THIS AIRPLANE IN PARTICULAR. NOTHING OUT OF THE ORDINARY OCCURRED ENRTE. APCHING SAIPAN, WE RECEIVED THE WX OVER VOICE AND VIA ACARS. WE KNEW THERE WOULD BE RAIN SHOWERS OVER THE AREA, RAGGED CEILINGS, AND GUSTY WINDS. IN BRIEFING THE APCH, DISCUSSION INCLUDED SELECTING MINIMUM BRAKES DUE TO A POSSIBLY WET RWY. THE CAPT VOICED THE OPINION THAT AT OUR GROSS WT, ABOUT 580000 LBS, WE DID NOT WANT A PROB LNDG LONG ON THE 7500 FT RWY. PREVIOUS EXPERIENCE INTO SAIPAN HAD SHOWN THAT WITH AN EARLY DSCNT, OFTENTIMES ONE COULD VISUALLY OBTAIN THE RWY EARLY ENOUGH SO AS TO PRECLUDE LENGTHY VECTORING. THAT WAS THE PLAN UNTIL WE WERE INFORMED THAT WE WERE #3 FOR APCH AND LNDG, TO SLOW UP SOME 100 MI FROM THE FIELD, AND THAT THERE WERE RAIN SHOWERS ON FINAL, SO WE WERE TO EXPECT THE ILS TO RWY 7. WE WERE GIVEN DELAYING VECTORS, AND SOME 30 MI FROM THE FIELD, WE WERE FINALLY GIVEN A HEADING TO INTERCEPT THE LOC. AT 5000 FT MSL ON FINAL APCH, WE DECIDED TO FOLLOW THE GS DOWN. ONCE ON FINAL, HAVING SLOWED TO MANEUVERING AIRSPD WITH FLAPS OUT AT 10 DEGS, THEN 20 DEGS WITH GEAR DOWN, THEN 25 DEGS, I NOTICED IT WAS TAKING MUCH EFFORT TO CTL ACFT HEADING WITHIN +/-15 DEGS EITHER SIDE OF COURSE. THIS WAS IN MY MIND A LITTLE EXCESSIVE FOR THE WIND CONDITIONS, WHICH WERE PRETTY MUCH A STRAIGHT HEADWIND. PITCH CTL ALSO SEEMED SLIGHTLY HVY. DESPITE ALL OF THAT, THE OTHER CREW MEMBERS NOTED THAT I HAD THE APCH 'WIRED' (LITTLE DID THEY REALIZE HOW MUCH EFFORT I WAS PUTTING INTO CTLING THE ACFT TO MAKE IT SEEM THAT WAY). WE BROKE OUT ABOUT 1 1/2 MI OUT ONCE WE GOT BELOW THE RAGGED CEILING, ABOUT 500-600 FT MSL. I KEPT PEERING PERIODICALLY AT MY FLT INSTS WHILE TRANSITIONING TO A VISUAL APCH, UNTIL I KNEW WE WERE CLR OF ALL OBSCURATIONS. THE CAPT ANNOUNCED ON SHORT FINAL (100-200 FT AGL) THAT MY AIRSPD WAS ABOUT VREF, SO I ADDED A LITTLE PWR, KEEPING THE GUSTY WINDS IN MIND. I HEARD THE 100 FT VOICE COMMAND FLARE TONE, AND I KEPT THE DSCNT GOING. THE 30 FT VOICE COMMAND FLARE TONE WENT OFF, AND I STARTED FLARING. THE 20 FT VOICE COMMAND FLARE TONE THEN WENT OFF, AND I PULLED BACK MORE. IT DID NOT FEEL LIKE I COULD PULL THE NOSE UP ANY MORE, IT FELT AS IF SOMETHING WAS PUSHING DOWN ON THE ACFT. WE NEVER RECEIVED A SINK RATE OR ANY OTHER KIND OF WARNING THROUGHOUT THE APCH AND LNDG. THE ACFT TOUCHED DOWN STRAIGHT AHEAD WITH AN INCOMPLETE FLARE, ALMOST LIKE STUFFING A SHOE OR STUBBING A TOE. NO CRAB WAS FELT, AND WE TAXIED THE ACFT TO THE GATE PERFORMING THE NORMAL FLOW PATTERNS AND CHKLISTS WITHOUT INCIDENT. THE LNDG HAD BEEN FIRM, BUT WE ALL AGREED WE HAD BEEN PRIVY TO MUCH FIRMER, HARDER LNDGS. NO PANELS OR OXYGEN MASKS HAD FALLEN DOWN. ON THE SO'S SUBSEQUENT PREFLT 1 1/2 HRS LATER, HE DISCOVERED THE L INBOARD FLAP CANOE SEEMED TO HAVE COME DISLODGED, THE FLAP HAD IMPINGED THE L AILERON, AND A FLAP ROD ASSEMBLY HAD BROKEN OFF ITS BRACKET. WHETHER THIS MAINT PROB HAD OCCURRED WHILE BRINGING THE FLAPS UP, EITHER ON CLBOUT OR AFTER LNDG, OR WHILE BEING DEPLOYED, IS ANYONE'S GUESS RIGHT NOW. AS FAR AS THE LNDG WAS CONCERNED, IT MAY HAVE OCCURRED IN PART BY THE FLAP PROB, A DOWNDRAFT, OR A LOSS OF GUST. OTHER CONTRIBUTING FACTORS INCLUDED THE VOICE COMMAND FLARE TONES, LACK OF CREW EXPERIENCE (THE CAPT HAD JUST OVER 100 HRS TIME IN COMMAND OF THE B747, I HAVE JUST OVER 250 HRS AND 25 LNDGS IN THE B747) AND CHRONIC FATIGUE (THIS WAS DAY 13 OUT OF 14 ON THE ROAD FOR ME).

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.