Narrative:

Flight to suu (travis AFB). Upon landing at suu, my flight dispatcher informed me that the western air defense sector called, asking why we were not in communication with ATC controller for 1 hour 30 mins between ZDV and ZLC. We were never NORDO, didn't squawk 7600, nor did we receive any guard calls to contact ZLC. During the time in question, the flight was en route direct fqf under ZDV control. We requested and received authority/authorized to deviate south of course for WX, climbing to FL410, as I recall. 15 mins later, we reported clear of WX and ZDC cleared us direct coaldale (oal). During this period, we passed a prescribed company position report via cedar rapids. The flight plan ete for fqf was 3 hours 27 mins (ete at oal was 4 hours 53 mins), GS = 430 KTS. We had 1 more ZDV frequency change. After a period of silence following check-in with denver, I asked my first officer (PNF) to contact denver for a radio check. The first officer spent 15 mins attempting first denver and then ZLC frequencys. About 30 mins later, cedar rapids called us via cell call and instructed us to contact ZLC, which we continued to do. While on HF with cedar rapids, the captain provided an assist to company aircraft requesting a radio relay to receive a redispatch message from dispatch, which I facilitated while my first officer rolled through the list of frequencys (for center) on the hi altitude en route chart. I estimate we were aware of a lack of center contact for a period of approximately 30 mins, not 1 hour 30 mins as suggested by the western air defense sector. The flight followed the filed flight plan, save the WX deviation 15 NM south of course. At no time was any sense of urgency noted by the crew. A guard call would have been heard by one of my crew. Note: my #3 VHF radio had 121.5 entered and my communication volume on it was lower than #1 (center frequency) and #2 VHF (ATIS, station ground frequency, used by flight engineer). The long legs associated with INS direct routing may lead to a degree of complacency with regard to radio frequency changes since they occur less seldom under these circumstances. However, I did note to my crew we had not spoken with a center controller for some elapsed time and was attempting such contact when advised to do the same. On my next flight, I will have 127.45 on my 'extra' radio in addition to center frequency and guard.

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Original NASA ASRS Text

Title: A B747-200 CARGO FLT CREW IS ALLEGED TO BE OUT OF COM WITH ZDV AND ZLC FOR A PERIOD OF 1 HR 30 MINS WHILE BTWN FAF AND OAL ON A FLT TO SUU, CA.

Narrative: FLT TO SUU (TRAVIS AFB). UPON LNDG AT SUU, MY FLT DISPATCHER INFORMED ME THAT THE WESTERN AIR DEFENSE SECTOR CALLED, ASKING WHY WE WERE NOT IN COM WITH ATC CTLR FOR 1 HR 30 MINS BTWN ZDV AND ZLC. WE WERE NEVER NORDO, DIDN'T SQUAWK 7600, NOR DID WE RECEIVE ANY GUARD CALLS TO CONTACT ZLC. DURING THE TIME IN QUESTION, THE FLT WAS ENRTE DIRECT FQF UNDER ZDV CTL. WE REQUESTED AND RECEIVED AUTH TO DEVIATE S OF COURSE FOR WX, CLBING TO FL410, AS I RECALL. 15 MINS LATER, WE RPTED CLR OF WX AND ZDC CLRED US DIRECT COALDALE (OAL). DURING THIS PERIOD, WE PASSED A PRESCRIBED COMPANY POS RPT VIA CEDAR RAPIDS. THE FLT PLAN ETE FOR FQF WAS 3 HRS 27 MINS (ETE AT OAL WAS 4 HRS 53 MINS), GS = 430 KTS. WE HAD 1 MORE ZDV FREQ CHANGE. AFTER A PERIOD OF SILENCE FOLLOWING CHK-IN WITH DENVER, I ASKED MY FO (PNF) TO CONTACT DENVER FOR A RADIO CHK. THE FO SPENT 15 MINS ATTEMPTING FIRST DENVER AND THEN ZLC FREQS. ABOUT 30 MINS LATER, CEDAR RAPIDS CALLED US VIA CELL CALL AND INSTRUCTED US TO CONTACT ZLC, WHICH WE CONTINUED TO DO. WHILE ON HF WITH CEDAR RAPIDS, THE CAPT PROVIDED AN ASSIST TO COMPANY ACFT REQUESTING A RADIO RELAY TO RECEIVE A REDISPATCH MESSAGE FROM DISPATCH, WHICH I FACILITATED WHILE MY FO ROLLED THROUGH THE LIST OF FREQS (FOR CTR) ON THE HI ALT ENRTE CHART. I ESTIMATE WE WERE AWARE OF A LACK OF CTR CONTACT FOR A PERIOD OF APPROX 30 MINS, NOT 1 HR 30 MINS AS SUGGESTED BY THE WESTERN AIR DEFENSE SECTOR. THE FLT FOLLOWED THE FILED FLT PLAN, SAVE THE WX DEV 15 NM S OF COURSE. AT NO TIME WAS ANY SENSE OF URGENCY NOTED BY THE CREW. A GUARD CALL WOULD HAVE BEEN HEARD BY ONE OF MY CREW. NOTE: MY #3 VHF RADIO HAD 121.5 ENTERED AND MY COM VOLUME ON IT WAS LOWER THAN #1 (CTR FREQ) AND #2 VHF (ATIS, STATION GND FREQ, USED BY FE). THE LONG LEGS ASSOCIATED WITH INS DIRECT ROUTING MAY LEAD TO A DEGREE OF COMPLACENCY WITH REGARD TO RADIO FREQ CHANGES SINCE THEY OCCUR LESS SELDOM UNDER THESE CIRCUMSTANCES. HOWEVER, I DID NOTE TO MY CREW WE HAD NOT SPOKEN WITH A CTR CTLR FOR SOME ELAPSED TIME AND WAS ATTEMPTING SUCH CONTACT WHEN ADVISED TO DO THE SAME. ON MY NEXT FLT, I WILL HAVE 127.45 ON MY 'EXTRA' RADIO IN ADDITION TO CTR FREQ AND GUARD.

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.