Narrative:

Scheduled sfo-san. WX forecast in san to be above that which would require an alternate. Just before pushback in sfo WX in san dropped to 1900 ft broken. Dispatcher changed our hold fuel to alternate fuel and designated ont. Captain neglected to add fuel or declare alternate before push. ATIS at top of descent at san was 1900 ft broken, 3000 ft overcast, 15 mi visibility in light rain. Temperature 57 degrees, dewpoint 51 degrees. While being vectored first officer obtained new ATIS indicating 1900 ft overcast 2 1/2 mi visibility in light rain, temperature 56 degrees and dewpoint 51 degrees with localizer runway 27 in use. Very long final resulted in more fuel used than planned. Approximately 10 mi final crew heard previous 2 or 3 aircraft go missed approach. WX obviously went rapidly down. We did not see runway until well past visual descent point at san and went missed approach too. San approach was now vectoring all missed approach aircraft for a teardrop back to runway 9 for the ILS, but said it may be a while because there were still some aircraft on the runway 27 approach. We both noted we were now below divert and far alternate fuel. I recommended declaring minimum fuel and being #1 for the ILS. We heard someone ask for the WX at mirimar and it was also bad. The captain noted the high minimums (decision ht) for the san ILS runway 9 and said we had to divert to ont, now. After a short discussion we headed for ont. I recommended that we climb higher than the planned divert altitude of 10000 ft and declare emergency fuel. The captain felt we were ok. I checked ont WX and it was also well below forecast. Lax was much better. I notified dispatch, his reply was total confusion why we would be diverting, he was clueless. Lax approach gave us very direct routing and we were on a nice vertical profile but a cutoff vector caused the captain to become high on his approach. He had been 2 dots high but was correcting down to about 1 DOT high at about 5-8 mi out. We had about 3000 pounds of fuel at this point. Still in the clouds with 1500-2000 FPM down at about 1800 ft or less both ILS displays in both course and glide path disappeared. I assume, the signal was interrupted for some unknown reason. I knew we did not have fuel to go around safely so I was directive and said to the captain that we needed to follow the map display and descend to 500 ft. He was somewhat panicked and repeatedly said 'where did it go, what happened.' we broke out and were well left when the ILS signal returned. We found runway 25L and landed safely. Fuel at block-in was approximately 2500 pounds.

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Original NASA ASRS Text

Title: A B737-300 FLC DIVERTED AS A RESULT OF A LOW FUEL CONDITION.

Narrative: SCHEDULED SFO-SAN. WX FORECAST IN SAN TO BE ABOVE THAT WHICH WOULD REQUIRE AN ALTERNATE. JUST BEFORE PUSHBACK IN SFO WX IN SAN DROPPED TO 1900 FT BROKEN. DISPATCHER CHANGED OUR HOLD FUEL TO ALTERNATE FUEL AND DESIGNATED ONT. CAPT NEGLECTED TO ADD FUEL OR DECLARE ALTERNATE BEFORE PUSH. ATIS AT TOP OF DSCNT AT SAN WAS 1900 FT BROKEN, 3000 FT OVCST, 15 MI VISIBILITY IN LIGHT RAIN. TEMP 57 DEGS, DEWPOINT 51 DEGS. WHILE BEING VECTORED FO OBTAINED NEW ATIS INDICATING 1900 FT OVCST 2 1/2 MI VISIBILITY IN LIGHT RAIN, TEMP 56 DEGS AND DEWPOINT 51 DEGS WITH LOC RWY 27 IN USE. VERY LONG FINAL RESULTED IN MORE FUEL USED THAN PLANNED. APPROX 10 MI FINAL CREW HEARD PREVIOUS 2 OR 3 ACFT GO MISSED APCH. WX OBVIOUSLY WENT RAPIDLY DOWN. WE DID NOT SEE RWY UNTIL WELL PAST VISUAL DSCNT POINT AT SAN AND WENT MISSED APCH TOO. SAN APCH WAS NOW VECTORING ALL MISSED APCH ACFT FOR A TEARDROP BACK TO RWY 9 FOR THE ILS, BUT SAID IT MAY BE A WHILE BECAUSE THERE WERE STILL SOME ACFT ON THE RWY 27 APCH. WE BOTH NOTED WE WERE NOW BELOW DIVERT AND FAR ALTERNATE FUEL. I RECOMMENDED DECLARING MINIMUM FUEL AND BEING #1 FOR THE ILS. WE HEARD SOMEONE ASK FOR THE WX AT MIRIMAR AND IT WAS ALSO BAD. THE CAPT NOTED THE HIGH MINIMUMS (DECISION HT) FOR THE SAN ILS RWY 9 AND SAID WE HAD TO DIVERT TO ONT, NOW. AFTER A SHORT DISCUSSION WE HEADED FOR ONT. I RECOMMENDED THAT WE CLB HIGHER THAN THE PLANNED DIVERT ALT OF 10000 FT AND DECLARE EMER FUEL. THE CAPT FELT WE WERE OK. I CHKED ONT WX AND IT WAS ALSO WELL BELOW FORECAST. LAX WAS MUCH BETTER. I NOTIFIED DISPATCH, HIS REPLY WAS TOTAL CONFUSION WHY WE WOULD BE DIVERTING, HE WAS CLUELESS. LAX APCH GAVE US VERY DIRECT ROUTING AND WE WERE ON A NICE VERT PROFILE BUT A CUTOFF VECTOR CAUSED THE CAPT TO BECOME HIGH ON HIS APCH. HE HAD BEEN 2 DOTS HIGH BUT WAS CORRECTING DOWN TO ABOUT 1 DOT HIGH AT ABOUT 5-8 MI OUT. WE HAD ABOUT 3000 LBS OF FUEL AT THIS POINT. STILL IN THE CLOUDS WITH 1500-2000 FPM DOWN AT ABOUT 1800 FT OR LESS BOTH ILS DISPLAYS IN BOTH COURSE AND GLIDE PATH DISAPPEARED. I ASSUME, THE SIGNAL WAS INTERRUPTED FOR SOME UNKNOWN REASON. I KNEW WE DID NOT HAVE FUEL TO GO AROUND SAFELY SO I WAS DIRECTIVE AND SAID TO THE CAPT THAT WE NEEDED TO FOLLOW THE MAP DISPLAY AND DSND TO 500 FT. HE WAS SOMEWHAT PANICKED AND REPEATEDLY SAID 'WHERE DID IT GO, WHAT HAPPENED.' WE BROKE OUT AND WERE WELL L WHEN THE ILS SIGNAL RETURNED. WE FOUND RWY 25L AND LANDED SAFELY. FUEL AT BLOCK-IN WAS APPROX 2500 LBS.

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.