Narrative:

Just prior to 74W we were asked to squawk standby by center, unusual but we followed directions. A few mins later they asked us to squawk normal. Shortly after we were told to contact montreal frequency 134.25 at 74W. PF followed instructions. When we could not raise montreal on 134.25 at 74W the old frequency was tried with no luck. Other frequencys from the canadian chart used with no luck until edmonton heard us and directed us to a correct frequency. Time elapsed approximately 10-15 mins. During this time dispatch sent us a request for operations normal. At this time no reason to believe anything was irregular or that there was a security problem. We replied operations normal. We received 4 more operations normal requests which we responded to. On the last one I asked how they wanted us to respond. We were asked to contact dispatch on satcom. We did. Dispatch said norad was concerned that we had squawked 7500 and dispatch was concerned that we may be intercepted. He referred us to page 90.20.3 in the fom. We reviewed it and sent the reply he wanted on ACARS. Dispatch also asked us our birth dates and company hire dates. We responded and were sent a 'thanks...rcaf is standing down.' the flight continued with a normal landing in lhr. During the incident we never, to my knowledge, changed our squawk. We only went from normal to standby and back to normal. Supplemental information from acn 610747: while attempting to contact montreal on 134.25 at n56w074 as assigned, I could not raise montreal. I then used ca hi 4 chart to try several (5) other possible controling frequencys. Please note that they both requested our confirm operations normal without using the proper format outline on page 9.20.3 of our fom -- it should have been, 'flight abc confirm operations normal.' with respect to the squawking of 7500, we never changed our squawk to 7500. We were using the right transponder on TA/RA during this incident. Previous to the temporary loss of radio contact, montreal asked us to squawk standby for about 5 mins before asking us to return to normal squawk. I thought this a bit unusual, but it did not register with me as a security related issue. Supplemental information from acn 610748: after briefing crew I went on crew rest and event happened while I was asleep. Dispatch stated that radar was reading a 7500 squawk from our flight. The transponder was never at 7500 for the entire flight.

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Original NASA ASRS Text

Title: A NEAR AIR INTERCEPT FOR A B747-400 WHEN MONTREAL CTR ADVISES NORAD AND COMPANY OF LOST COM AND CODE 7500 INCIDENT NEAR N56W74 ON A POLAR FLT OFF FREQ WITH CZUL, PQ.

Narrative: JUST PRIOR TO 74W WE WERE ASKED TO SQUAWK STANDBY BY CTR, UNUSUAL BUT WE FOLLOWED DIRECTIONS. A FEW MINS LATER THEY ASKED US TO SQUAWK NORMAL. SHORTLY AFTER WE WERE TOLD TO CONTACT MONTREAL FREQ 134.25 AT 74W. PF FOLLOWED INSTRUCTIONS. WHEN WE COULD NOT RAISE MONTREAL ON 134.25 AT 74W THE OLD FREQ WAS TRIED WITH NO LUCK. OTHER FREQS FROM THE CANADIAN CHART USED WITH NO LUCK UNTIL EDMONTON HEARD US AND DIRECTED US TO A CORRECT FREQ. TIME ELAPSED APPROX 10-15 MINS. DURING THIS TIME DISPATCH SENT US A REQUEST FOR OPS NORMAL. AT THIS TIME NO REASON TO BELIEVE ANYTHING WAS IRREGULAR OR THAT THERE WAS A SECURITY PROB. WE REPLIED OPS NORMAL. WE RECEIVED 4 MORE OPS NORMAL REQUESTS WHICH WE RESPONDED TO. ON THE LAST ONE I ASKED HOW THEY WANTED US TO RESPOND. WE WERE ASKED TO CONTACT DISPATCH ON SATCOM. WE DID. DISPATCH SAID NORAD WAS CONCERNED THAT WE HAD SQUAWKED 7500 AND DISPATCH WAS CONCERNED THAT WE MAY BE INTERCEPTED. HE REFERRED US TO PAGE 90.20.3 IN THE FOM. WE REVIEWED IT AND SENT THE REPLY HE WANTED ON ACARS. DISPATCH ALSO ASKED US OUR BIRTH DATES AND COMPANY HIRE DATES. WE RESPONDED AND WERE SENT A 'THANKS...RCAF IS STANDING DOWN.' THE FLT CONTINUED WITH A NORMAL LNDG IN LHR. DURING THE INCIDENT WE NEVER, TO MY KNOWLEDGE, CHANGED OUR SQUAWK. WE ONLY WENT FROM NORMAL TO STANDBY AND BACK TO NORMAL. SUPPLEMENTAL INFO FROM ACN 610747: WHILE ATTEMPTING TO CONTACT MONTREAL ON 134.25 AT N56W074 AS ASSIGNED, I COULD NOT RAISE MONTREAL. I THEN USED CA HI 4 CHART TO TRY SEVERAL (5) OTHER POSSIBLE CTLING FREQS. PLEASE NOTE THAT THEY BOTH REQUESTED OUR CONFIRM OPS NORMAL WITHOUT USING THE PROPER FORMAT OUTLINE ON PAGE 9.20.3 OF OUR FOM -- IT SHOULD HAVE BEEN, 'FLT ABC CONFIRM OPS NORMAL.' WITH RESPECT TO THE SQUAWKING OF 7500, WE NEVER CHANGED OUR SQUAWK TO 7500. WE WERE USING THE RIGHT XPONDER ON TA/RA DURING THIS INCIDENT. PREVIOUS TO THE TEMPORARY LOSS OF RADIO CONTACT, MONTREAL ASKED US TO SQUAWK STANDBY FOR ABOUT 5 MINS BEFORE ASKING US TO RETURN TO NORMAL SQUAWK. I THOUGHT THIS A BIT UNUSUAL, BUT IT DID NOT REGISTER WITH ME AS A SECURITY RELATED ISSUE. SUPPLEMENTAL INFO FROM ACN 610748: AFTER BRIEFING CREW I WENT ON CREW REST AND EVENT HAPPENED WHILE I WAS ASLEEP. DISPATCH STATED THAT RADAR WAS READING A 7500 SQUAWK FROM OUR FLT. THE XPONDER WAS NEVER AT 7500 FOR THE ENTIRE FLT.

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.