Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Other / Unknown
Inflight Event / Encounter Other / Unknown
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Overcame Equipment Problem
Aircraft; Environment - Non Weather Related; Human Factors
We were flying along; and noticed that we were getting high for our approach. I contacted ATC who did not respond. Our last transmission was as clear as a bell; and had been about 10 or 15 minutes ago. After numerous attempts to contact them I was able to get another Controller on 121.5. While the other Controller was looking for our frequency I received a call on our original frequency. ATC claimed that they had been trying to contact us for the last 60 miles. They got us on the correct frequency. I'm still not sure what happened. I sincerely believe that we did not receive any transmissions. There was some military action in the area; GPS jamming; and a number of aircraft including us has our GPS signals interrupted; and I wonder if that had something to do with blocking transmissions. Also ATC sometimes uses transmitters that are too far away from our aircraft to hear. I wonder if this had been the case when they were trying to contact us. This might have been my fault; but I don't think so. I think that ATC should be more aggressive when they are trying to contact an airplane. They should use the other aircraft around them to try to raise the missing flight. Also [ATC] center's should monitor 121.5! I had a heck of time trying to get someone to respond on that frequency! It would be cool also if our release contained a list of expected frequencies that would be used during our flight.
Our flight was uneventful until shortly after Center advised us that GPS jamming operations were being conducted ahead of us along our route of flight and to let Center know if we were affected. We then began confirming that we had the proper VOR navigation backing up our route of flight. In addition the Captain as pilot not flying selected LRN POS in the FMS. Just as he selected LRN POS the FMS completely failed. We then proceeded to notify ATC that not only did we lose our GPS; but that we lost our entire FMS computer. Center then began giving us headings to fly which according to our VOR navigation kept us on the airway we had originally been cleared to fly. We were at FL370 so I figured we needed to begin our descent to our destination no later than roughly 110 NM out. As we were listening to Center and waiting for our clearance for lower we heard Center talking to other aircraft but not us. As we were getting closer to our descent point the radios were silent so we gave Center a radio call requesting lower; but there was no response. After a few attempts to make contact with Center the Captain proceeded to call on Guard and was able to get in touch with a different ATC facility with some effort; however as we were talking to him we finally heard Center calling us on the frequency we originally were on. But by this time we were already 60 NM from our destination and had been attempting to contact center for roughly 60 NM or ten minutes. Center was then promptly able to give us vectors followed by a descent that allowed us to complete the flight without further incident. Shortly after we had re-established contact with Center we received an ACARS message from Company Dispatch directing us to contact Center. We do not know why we could not hear Center and/or why Center could not hear us; however; we don't know if there may have been radio interference related to the GPS jamming that was being conducted in the area. Center claimed he was trying to contact us at the same time we know we were trying to contact him. This was some form of equipment failure.
CRJ700 flight crew is advised by ATC of GPS jamming ahead. When the jamming is encountered not only does the GPS fail but so does the FMC and VHF. Lost communication results in a late descent clearance for landing.