B777 Undifferentiated or Other Model
Flight Crew Last 90 Days 139; Flight Crew Total 14313; Flight Crew Type 3896
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem
Aircraft
Reaching cruise at FL370; a system malfunction caused the loss of transponder and TCAS.  Unable RVSM; ATC descended us to FL270.  After conferring with [Maintenance]; it appeared to be a failed AIMS (Air Data Module) module with no possible attempt at a reset.  All navigation and remaining avionics were operating normally.  Dispatch worked up [a new release] with a re-dispatch intermediate destination. I agreed and accepted the RLS (release) and we proceeded on to FRA at FL270; but it was going to be tight at the re-dispatch point and as we continued on we definitely felt the need for a higher altitude to make a successful dispatch all the way to FRA. Referencing FOM (Flight Operations Manual) we managed to get FL330 from Gander Oceanic as they guaranteed 2;000 ft vertical separation.  We were very proactive entering each ATC area that all were aware and approved 2;000 ft vertical separation. This worked thru London airspace; then it was back down to FL270.  Landed uneventfully in FRA with 12.5 fuel at touchdown. Just an awkward and unusual situation for me.  Great crew; teamwork and resource utilization.
[Report narrative contained no additional information.]
B777 flight crew reported their aircraft became non-RVSM on their trans-Atlantic flight.