Narrative:

MEL-standby gyro inoperative at departure. 7TH time in a few weeks. MEL says VFR daylight only; no penetration of cloud decks (as I remember/understood). We worked with dispatch and clarified per MEL that we had to wait for sunrise (not dawn; sunrise -30 mins; but sunrise) before we could take off. After MEL determination and agreement with dispatch; we checked paperwork for forecast WX and noted a tempo line with overcast conditions for our new proposed arrival time; called dispatch and queried about WX and our legality; and forecasted WX. The reply from dispatch was that 'you'll be good.' based on that; we launched. At the united states border; an undercast was observed. Captain and I discussed legality; and even though standby attitude indicator seemed to work (after both generators powered up on start) his recommendation was good with me that because it was in the book it would be illegal to use even though it appeared to be fine. I agreed; safety first; and we contacted dispatch. We were fueled for VFR arrival (remember 'you'll be good' pre-launch) at ZZZ1 and the nearest VFR alternate was ZZZ2. After a quick check of our data/fuel/distance and dispatch's advice; we went to ZZZ2; landed uneventfully; took fuel; and since unable to clear customs at ZZZ2 (non international field/no customs) dispatch wanted us to go to ZZZ3 to clear customs as forecasted WX at ZZZ1 was not to improve to VFR until later. We refueled with engine running at ZZZ2 (APU inoperative as well before we left and no start cart); got food for passenger; and launched for VFR and customs capable ZZZ3. Landed uneventfully at ZZZ3; cleared customs; refueled; WX cleared at ZZZ1 and we launched for ZZZ1. Lesson learned for me (future operations/flts): get anal and into the details about WX question; dig deeper than trusting a simple 'you'll be good' from dispatch; and ask specific questions with regard to WX; forecast; tempo lines; tempo and changes between WX of printed flight plan (based on time); and forecast WX at time of predicted delays; new expected arrival times; predicted change/edcts/updates of temperature line; and add fuel (for MEL and no APU) for holding and divert to VFR alternate in case forecast for good WX didn't happen (as in this case!).

Related reports:

Google
 

Original NASA ASRS Text

Title: MD80 WAS DISPATCHED WITH THE STANDBY ATTITUDE INDICATOR DEFERRED. THIS RESTRICTED THE ACFT TO DAY VFR. WX AT DEST RESULTED IN THE FLT CREW DIVERTING.

Narrative: MEL-STANDBY GYRO INOP AT DEP. 7TH TIME IN A FEW WKS. MEL SAYS VFR DAYLIGHT ONLY; NO PENETRATION OF CLOUD DECKS (AS I REMEMBER/UNDERSTOOD). WE WORKED WITH DISPATCH AND CLARIFIED PER MEL THAT WE HAD TO WAIT FOR SUNRISE (NOT DAWN; SUNRISE -30 MINS; BUT SUNRISE) BEFORE WE COULD TAKE OFF. AFTER MEL DETERMINATION AND AGREEMENT WITH DISPATCH; WE CHKED PAPERWORK FOR FORECAST WX AND NOTED A TEMPO LINE WITH OVCST CONDITIONS FOR OUR NEW PROPOSED ARR TIME; CALLED DISPATCH AND QUERIED ABOUT WX AND OUR LEGALITY; AND FORECASTED WX. THE REPLY FROM DISPATCH WAS THAT 'YOU'LL BE GOOD.' BASED ON THAT; WE LAUNCHED. AT THE UNITED STATES BORDER; AN UNDERCAST WAS OBSERVED. CAPT AND I DISCUSSED LEGALITY; AND EVEN THOUGH STANDBY ATTITUDE INDICATOR SEEMED TO WORK (AFTER BOTH GENERATORS POWERED UP ON START) HIS RECOMMENDATION WAS GOOD WITH ME THAT BECAUSE IT WAS IN THE BOOK IT WOULD BE ILLEGAL TO USE EVEN THOUGH IT APPEARED TO BE FINE. I AGREED; SAFETY FIRST; AND WE CONTACTED DISPATCH. WE WERE FUELED FOR VFR ARR (REMEMBER 'YOU'LL BE GOOD' PRE-LAUNCH) AT ZZZ1 AND THE NEAREST VFR ALTERNATE WAS ZZZ2. AFTER A QUICK CHK OF OUR DATA/FUEL/DISTANCE AND DISPATCH'S ADVICE; WE WENT TO ZZZ2; LANDED UNEVENTFULLY; TOOK FUEL; AND SINCE UNABLE TO CLR CUSTOMS AT ZZZ2 (NON INTL FIELD/NO CUSTOMS) DISPATCH WANTED US TO GO TO ZZZ3 TO CLR CUSTOMS AS FORECASTED WX AT ZZZ1 WAS NOT TO IMPROVE TO VFR UNTIL LATER. WE REFUELED WITH ENG RUNNING AT ZZZ2 (APU INOP AS WELL BEFORE WE LEFT AND NO START CART); GOT FOOD FOR PAX; AND LAUNCHED FOR VFR AND CUSTOMS CAPABLE ZZZ3. LANDED UNEVENTFULLY AT ZZZ3; CLRED CUSTOMS; REFUELED; WX CLRED AT ZZZ1 AND WE LAUNCHED FOR ZZZ1. LESSON LEARNED FOR ME (FUTURE OPS/FLTS): GET ANAL AND INTO THE DETAILS ABOUT WX QUESTION; DIG DEEPER THAN TRUSTING A SIMPLE 'YOU'LL BE GOOD' FROM DISPATCH; AND ASK SPECIFIC QUESTIONS WITH REGARD TO WX; FORECAST; TEMPO LINES; TEMPO AND CHANGES BTWN WX OF PRINTED FLT PLAN (BASED ON TIME); AND FORECAST WX AT TIME OF PREDICTED DELAYS; NEW EXPECTED ARR TIMES; PREDICTED CHANGE/EDCTS/UPDATES OF TEMP LINE; AND ADD FUEL (FOR MEL AND NO APU) FOR HOLDING AND DIVERT TO VFR ALTERNATE IN CASE FORECAST FOR GOOD WX DIDN'T HAPPEN (AS IN THIS CASE!).

Data retrieved from NASA's ASRS site as of May 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.