Narrative:

Lear jet, aircraft X departed VFR from lci at approximately XA20. After departure, we received an IFR clearance from manchester approach control. While flying on an assigned heading, we received an amendment to our clearance to fly present position direct to hvq VORTAC. While continuing our climb to the altitude received in our clearance, I programmed hvq VORTAC into the GPS and dialed the hvq frequency into both navigation radios. After programming the GPS, a course and heading to hvq was not available due to a 'raim' warning on our GPS unit. I wanted to report our navigation system warning to ATC, but the frequency was extremely busy at that time. The copilot (PF) turned 30-40 degrees left off our westerly assigned heading to proceed direct to hvq VORTAC according to our #1 and #2 VHF navigation. The frequency of hvq had been tuned into both navigation radios but had not been idented yet. As we continued our climb on a southwest course, I was waiting for a free and clear movement to contact and advise ATC of our situation, when, in fact, ATC made contact with us and told us to turn back to a westerly heading due to traffic. I advised ATC of our situation and he expressed concern that we did not advise him earlier. I explained that I was waiting for an opening on the frequency. After several mins, the 'raim' warning cleared on our GPS unit and we continued direct to hvq via our own navigation.

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Original NASA ASRS Text

Title: LR35 CREW, UNABLE TO COMMUNICATE WITH ZBW, HAD SYS MALFUNCTION WITH GPS EQUIP AND TURN OFF ASSIGNED RTE TO A VOR RTE.

Narrative: LEAR JET, ACFT X DEPARTED VFR FROM LCI AT APPROX XA20. AFTER DEP, WE RECEIVED AN IFR CLRNC FROM MANCHESTER APCH CTL. WHILE FLYING ON AN ASSIGNED HDG, WE RECEIVED AN AMENDMENT TO OUR CLRNC TO FLY PRESENT POS DIRECT TO HVQ VORTAC. WHILE CONTINUING OUR CLB TO THE ALT RECEIVED IN OUR CLRNC, I PROGRAMMED HVQ VORTAC INTO THE GPS AND DIALED THE HVQ FREQ INTO BOTH NAV RADIOS. AFTER PROGRAMMING THE GPS, A COURSE AND HDG TO HVQ WAS NOT AVAILABLE DUE TO A 'RAIM' WARNING ON OUR GPS UNIT. I WANTED TO RPT OUR NAV SYS WARNING TO ATC, BUT THE FREQ WAS EXTREMELY BUSY AT THAT TIME. THE COPLT (PF) TURNED 30-40 DEGS L OFF OUR WESTERLY ASSIGNED HDG TO PROCEED DIRECT TO HVQ VORTAC ACCORDING TO OUR #1 AND #2 VHF NAV. THE FREQ OF HVQ HAD BEEN TUNED INTO BOTH NAV RADIOS BUT HAD NOT BEEN IDENTED YET. AS WE CONTINUED OUR CLB ON A SW COURSE, I WAS WAITING FOR A FREE AND CLR MOVEMENT TO CONTACT AND ADVISE ATC OF OUR SIT, WHEN, IN FACT, ATC MADE CONTACT WITH US AND TOLD US TO TURN BACK TO A WESTERLY HDG DUE TO TFC. I ADVISED ATC OF OUR SIT AND HE EXPRESSED CONCERN THAT WE DID NOT ADVISE HIM EARLIER. I EXPLAINED THAT I WAS WAITING FOR AN OPENING ON THE FREQ. AFTER SEVERAL MINS, THE 'RAIM' WARNING CLRED ON OUR GPS UNIT AND WE CONTINUED DIRECT TO HVQ VIA OUR OWN NAV.

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.