Narrative:

Flight from ewr to nrt released with right pitot heat inoperative. Instructions to stay out of visible moisture. On ground ewr, first officer found right pitot heat inoperative. Maintenance notified and said it's probably an indicator problem. The new release was sent over ACARS just before engine start. While en route we noticed the right mach indicator was at times erratic. Communication was bad from edmonton and we started trying to contact dispatch around XA00Z and was not able to make contact for 30-40 mins. Tried ACARS, HF, etc. We needed to get nrt forecast to see if we were legal for redispatch. We finally made contact approaching nome and diverted to sfo. Looking back, I feel everyone was too concerned about an 'on time' departure. After maintenance statement that it's probably an indication failure, we initially believed that to be the case. Maintenance didn't say anything else when we got the new release. We realized that it was a bad pitot heater when we saw the right mach indication was different from left one. We need better communications between cockpit and maintenance about items affecting flight operations. It also appears we have a communication problem in the area from edmonton and nome. We were being put into a position of going into russian airspace without knowing the WX in nrt and then not being able to accept a redispatch because of possible icing on letdown in nrt. Callback conversation with reporter revealed the following information: the pitot heat light came on shortly before departure and when questioned by the flight crew, maintenance advised that it was just an indicator and, that even with just 1 system, it was legal per MEL for dispatch. The flight crew was advised, however, that they could not fly into or through icing conditions. The WX on this long (13 hour ewr-nrt) flight was forecast good as far as shemya. The flight crew intended to get more updated WX and reclrnc en route. After takeoff during climb out, the flight crew noted erratic pitot static readings, but they normalized at higher altitudes. In western canada the flight crew had problems establishing communication in order to get a WX update and reclrnc. By the time they re-established communication, they had begun to experience erratic pitot static readouts, even though the WX was clear. Because of the pitot problem and the WX had deteriorated west of shemya, the flight crew and dispatch agreed to divert the flight to sfo from nome. Reporter believes that the MEL should not permit such long flts to be dispatched with an inoperative pitot system. Callback conversation with dispatcher acn #315085 revealed the following information: original dispatch WX was good all the way so the dispatcher was comfortable with the requirement of staying clear of icing conditions. But, when a current WX update came in just prior to the aircraft departure, which was deteriorating at the destination, dispatcher realized that the aircraft could not be dispatched with an inoperative pitot heat. Maintenance assured the dispatcher that the system was working properly and was just an indicator. Maintenance also advised the captain that it was just an indicator, which shortly after takeoff proved false.

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Original NASA ASRS Text

Title: DEFERRED PITOT HEAT. QUESTIONABLE MAINT PROC AND DISPATCH COORD.

Narrative: FLT FROM EWR TO NRT RELEASED WITH R PITOT HEAT INOP. INSTRUCTIONS TO STAY OUT OF VISIBLE MOISTURE. ON GND EWR, FO FOUND R PITOT HEAT INOP. MAINT NOTIFIED AND SAID IT'S PROBABLY AN INDICATOR PROB. THE NEW RELEASE WAS SENT OVER ACARS JUST BEFORE ENG START. WHILE ENRTE WE NOTICED THE R MACH INDICATOR WAS AT TIMES ERRATIC. COM WAS BAD FROM EDMONTON AND WE STARTED TRYING TO CONTACT DISPATCH AROUND XA00Z AND WAS NOT ABLE TO MAKE CONTACT FOR 30-40 MINS. TRIED ACARS, HF, ETC. WE NEEDED TO GET NRT FORECAST TO SEE IF WE WERE LEGAL FOR REDISPATCH. WE FINALLY MADE CONTACT APCHING NOME AND DIVERTED TO SFO. LOOKING BACK, I FEEL EVERYONE WAS TOO CONCERNED ABOUT AN 'ON TIME' DEP. AFTER MAINT STATEMENT THAT IT'S PROBABLY AN INDICATION FAILURE, WE INITIALLY BELIEVED THAT TO BE THE CASE. MAINT DIDN'T SAY ANYTHING ELSE WHEN WE GOT THE NEW RELEASE. WE REALIZED THAT IT WAS A BAD PITOT HEATER WHEN WE SAW THE R MACH INDICATION WAS DIFFERENT FROM L ONE. WE NEED BETTER COMS BTWN COCKPIT AND MAINT ABOUT ITEMS AFFECTING FLT OPS. IT ALSO APPEARS WE HAVE A COM PROB IN THE AREA FROM EDMONTON AND NOME. WE WERE BEING PUT INTO A POS OF GOING INTO RUSSIAN AIRSPACE WITHOUT KNOWING THE WX IN NRT AND THEN NOT BEING ABLE TO ACCEPT A REDISPATCH BECAUSE OF POSSIBLE ICING ON LETDOWN IN NRT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE PITOT HEAT LIGHT CAME ON SHORTLY BEFORE DEP AND WHEN QUESTIONED BY THE FLC, MAINT ADVISED THAT IT WAS JUST AN INDICATOR AND, THAT EVEN WITH JUST 1 SYS, IT WAS LEGAL PER MEL FOR DISPATCH. THE FLC WAS ADVISED, HOWEVER, THAT THEY COULD NOT FLY INTO OR THROUGH ICING CONDITIONS. THE WX ON THIS LONG (13 HR EWR-NRT) FLT WAS FORECAST GOOD AS FAR AS SHEMYA. THE FLC INTENDED TO GET MORE UPDATED WX AND RECLRNC ENRTE. AFTER TKOF DURING CLBOUT, THE FLC NOTED ERRATIC PITOT STATIC READINGS, BUT THEY NORMALIZED AT HIGHER ALTS. IN WESTERN CANADA THE FLC HAD PROBS ESTABLISHING COM IN ORDER TO GET A WX UPDATE AND RECLRNC. BY THE TIME THEY RE-ESTABLISHED COM, THEY HAD BEGUN TO EXPERIENCE ERRATIC PITOT STATIC READOUTS, EVEN THOUGH THE WX WAS CLR. BECAUSE OF THE PITOT PROB AND THE WX HAD DETERIORATED W OF SHEMYA, THE FLC AND DISPATCH AGREED TO DIVERT THE FLT TO SFO FROM NOME. RPTR BELIEVES THAT THE MEL SHOULD NOT PERMIT SUCH LONG FLTS TO BE DISPATCHED WITH AN INOP PITOT SYS. CALLBACK CONVERSATION WITH DISPATCHER ACN #315085 REVEALED THE FOLLOWING INFO: ORIGINAL DISPATCH WX WAS GOOD ALL THE WAY SO THE DISPATCHER WAS COMFORTABLE WITH THE REQUIREMENT OF STAYING CLR OF ICING CONDITIONS. BUT, WHEN A CURRENT WX UPDATE CAME IN JUST PRIOR TO THE ACFT DEP, WHICH WAS DETERIORATING AT THE DEST, DISPATCHER REALIZED THAT THE ACFT COULD NOT BE DISPATCHED WITH AN INOP PITOT HEAT. MAINT ASSURED THE DISPATCHER THAT THE SYS WAS WORKING PROPERLY AND WAS JUST AN INDICATOR. MAINT ALSO ADVISED THE CAPT THAT IT WAS JUST AN INDICATOR, WHICH SHORTLY AFTER TKOF PROVED FALSE.

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.