Narrative:

Flight departed for destination ZZZ with 22.9 fuel load (planned landing alternate of ZZZ1). At departure time; weather at ZZZ was forecast to be 2 SM with light snow; and ceilings of 1300 ft overcast. The flight proceeded normally until the initial descent to ZZZ. Weather at ZZZ had dropped to 4000 ft RVR. ATC issued holding instructions for published holding at abc; 22000 ft; efc XA20Z. The captain was in constant contact with ATC and dispatch (via ACARS) regarding our situation. It was mutually agreed upon that ZZZ2 (our next flight's destination) would be our new alternate. We were advised of a 3.9 en route burn to ZZZ2. With far reserves of 3.9 and the alternate fuel; we set 8.0 as our bingo fuel requirement. We held for approximately 15 minutes until ATC advised that we could head direct intersection cdefg and expect vectors for the approach. We descended to 8000 ft and prior to arriving at intersection cdefg were advised that the runway was being shut down for sweeping. We were given a clearance to hold at intersection cdefg as published; efc XA40Z. The weather at ZZZ was changing rapidly (4-5 sets of ATIS within at 20-25 minute time span). We were advised that the RVR was 3000 ft and started to set up for the captain to fly a CAT III approach. After 5-10 minutes of holding; the runway opened up and we departed holding on vectors for the approach. ATC then advised RVR of 2000 ft to 2500 ft and deteriorating. With 9000 pounds of fuel onboard; we elected to activate our diversion plan to ZZZ2 and were given a heading of 180 and climbed to 10000 ft; followed quickly by direct def and a climb to FL360. We were quite busy communicating with ATC; dispatch via ACARS; and reprogramming the FMC for our flight to ZZZ2. I felt very comfortable with our decision to divert and felt it was made with plenty of diversion fuel (9000 pounds; 1000 pounds more than we felt was needed). Upon level off; the FMC showed 5.0 for arrival fuel at ZZZ2. Since we had not entered en route winds for this leg; the FMC took a little time to update with the current winds (in effect a 100 knot headwind) and the landing fuel started methodically dropping towards 4.0. The captain advised center that we could not accept many vectors without having to declare minimum fuel. Center asked if we were declaring an emergency; the captain replied in the negative. We were descended to FL340; 200 NM from def and shortly thereafter to FL320; adding to our fuel burn concern. Center then descended us to FL240 150 NM from def. We were handed off to approach control; advised them of 'minimum fuel' and were given direct to ZZZ2 for arrival. I flew a visual approach to runway; landing the aircraft with 3400 pounds of fuel onboard; below our far reserves of 3900 pounds. Better understanding of the diversion plan; especially what forecast winds are for the route. Also; from what point was the diversion plan valid (the holding fix or the FAF for the approach). I think in our situation; the diversion plan was based on departing for ZZZ2 from the holding fix at abc; 22000 ft and not from intersection cdef after holding and vectors at 8000 ft; potentially putting us below the planned diversion fuel load. The workload of the ATC environment; raw data holding patterns; and coordinating diversion plans were all threats attempting to reduce our situational awareness. Failing to enter some kind of forecast cruise winds when executing the diversion plan led to a delay in recognizing the reduced landing fuel situation further in advance.

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Original NASA ASRS Text

Title: A B737-500 FLT BYPASSED THE INTENDED DEST AND ITS ALTERNATE BECAUSE OF WX. THE FLT LANDED BELOW FAR FUEL REQUIREMENTS AT THE NEXT SCHEDULED DEST.

Narrative: FLIGHT DEPARTED FOR DESTINATION ZZZ WITH 22.9 FUEL LOAD (PLANNED LANDING ALTERNATE OF ZZZ1). AT DEPARTURE TIME; WEATHER AT ZZZ WAS FORECAST TO BE 2 SM WITH LIGHT SNOW; AND CEILINGS OF 1300 FT OVERCAST. THE FLIGHT PROCEEDED NORMALLY UNTIL THE INITIAL DESCENT TO ZZZ. WEATHER AT ZZZ HAD DROPPED TO 4000 FT RVR. ATC ISSUED HOLDING INSTRUCTIONS FOR PUBLISHED HOLDING AT ABC; 22000 FT; EFC XA20Z. THE CAPTAIN WAS IN CONSTANT CONTACT WITH ATC AND DISPATCH (VIA ACARS) REGARDING OUR SITUATION. IT WAS MUTUALLY AGREED UPON THAT ZZZ2 (OUR NEXT FLIGHT'S DESTINATION) WOULD BE OUR NEW ALTERNATE. WE WERE ADVISED OF A 3.9 ENRTE BURN TO ZZZ2. WITH FAR RESERVES OF 3.9 AND THE ALTERNATE FUEL; WE SET 8.0 AS OUR BINGO FUEL REQUIREMENT. WE HELD FOR APPROXIMATELY 15 MINUTES UNTIL ATC ADVISED THAT WE COULD HEAD DIRECT INTXN CDEFG AND EXPECT VECTORS FOR THE APPROACH. WE DESCENDED TO 8000 FT AND PRIOR TO ARRIVING AT INTXN CDEFG WERE ADVISED THAT THE RUNWAY WAS BEING SHUT DOWN FOR SWEEPING. WE WERE GIVEN A CLEARANCE TO HOLD AT INTXN CDEFG AS PUBLISHED; EFC XA40Z. THE WEATHER AT ZZZ WAS CHANGING RAPIDLY (4-5 SETS OF ATIS WITHIN AT 20-25 MINUTE TIME SPAN). WE WERE ADVISED THAT THE RVR WAS 3000 FT AND STARTED TO SET UP FOR THE CAPTAIN TO FLY A CAT III APPROACH. AFTER 5-10 MINUTES OF HOLDING; THE RUNWAY OPENED UP AND WE DEPARTED HOLDING ON VECTORS FOR THE APPROACH. ATC THEN ADVISED RVR OF 2000 FT TO 2500 FT AND DETERIORATING. WITH 9000 LBS OF FUEL ONBOARD; WE ELECTED TO ACTIVATE OUR DIVERSION PLAN TO ZZZ2 AND WERE GIVEN A HEADING OF 180 AND CLIMBED TO 10000 FT; FOLLOWED QUICKLY BY DIRECT DEF AND A CLIMB TO FL360. WE WERE QUITE BUSY COMMUNICATING WITH ATC; DISPATCH VIA ACARS; AND REPROGRAMMING THE FMC FOR OUR FLIGHT TO ZZZ2. I FELT VERY COMFORTABLE WITH OUR DECISION TO DIVERT AND FELT IT WAS MADE WITH PLENTY OF DIVERSION FUEL (9000 LBS; 1000 LBS MORE THAN WE FELT WAS NEEDED). UPON LEVEL OFF; THE FMC SHOWED 5.0 FOR ARRIVAL FUEL AT ZZZ2. SINCE WE HAD NOT ENTERED ENRTE WINDS FOR THIS LEG; THE FMC TOOK A LITTLE TIME TO UPDATE WITH THE CURRENT WINDS (IN EFFECT A 100 KNOT HEADWIND) AND THE LANDING FUEL STARTED METHODICALLY DROPPING TOWARDS 4.0. THE CAPTAIN ADVISED CENTER THAT WE COULD NOT ACCEPT MANY VECTORS WITHOUT HAVING TO DECLARE MINIMUM FUEL. CENTER ASKED IF WE WERE DECLARING AN EMERGENCY; THE CAPTAIN REPLIED IN THE NEGATIVE. WE WERE DESCENDED TO FL340; 200 NM FROM DEF AND SHORTLY THEREAFTER TO FL320; ADDING TO OUR FUEL BURN CONCERN. CENTER THEN DESCENDED US TO FL240 150 NM FROM DEF. WE WERE HANDED OFF TO APPROACH CONTROL; ADVISED THEM OF 'MINIMUM FUEL' AND WERE GIVEN DIRECT TO ZZZ2 FOR ARRIVAL. I FLEW A VISUAL APPROACH TO RUNWAY; LANDING THE AIRCRAFT WITH 3400 LBS OF FUEL ONBOARD; BELOW OUR FAR RESERVES OF 3900 LBS. BETTER UNDERSTANDING OF THE DIVERSION PLAN; ESPECIALLY WHAT FORECAST WINDS ARE FOR THE ROUTE. ALSO; FROM WHAT POINT WAS THE DIVERSION PLAN VALID (THE HOLDING FIX OR THE FAF FOR THE APPROACH). I THINK IN OUR SITUATION; THE DIVERSION PLAN WAS BASED ON DEPARTING FOR ZZZ2 FROM THE HOLDING FIX AT ABC; 22000 FT AND NOT FROM INTXN CDEF AFTER HOLDING AND VECTORS AT 8000 FT; POTENTIALLY PUTTING US BELOW THE PLANNED DIVERSION FUEL LOAD. THE WORKLOAD OF THE ATC ENVIRONMENT; RAW DATA HOLDING PATTERNS; AND COORDINATING DIVERSION PLANS WERE ALL THREATS ATTEMPTING TO REDUCE OUR SITUATIONAL AWARENESS. FAILING TO ENTER SOME KIND OF FORECAST CRUISE WINDS WHEN EXECUTING THE DIVERSION PLAN LED TO A DELAY IN RECOGNIZING THE REDUCED LANDING FUEL SITUATION FURTHER IN ADVANCE.

Data retrieved from NASA's ASRS site as of January 2009 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.