8.4 Canadian Military Aircraft Communications System
If Crew are to unable to maintain contact with a HF operator or Arctic Radio, contact the Canadian Military Aircraft Communications System (MACS). Their main facility is in Trenton, Ontario and their call sign is Trenton Military.
Their coverage is excellent throughout the Polar Region. MACS routinely handle communications with military traffic throughout the Polar Region and communicates with the Rescue Coordination Center (RCC). They have SELCAL and phone patch capability, but do not have AFTN (Teletype) capability, so they cannot pass Teletype messages to air traffic control facilities, Trenton Military has advised us that they are happy to help with emergency or irregular operations. Their HF frequencies are 11232 and 9007.

9. ROUTE SPECIFICS
9.1 Enroute And Terminal Terrain
There is significant terrain depending upon the particular route in Greenland and also within Russia the Central Asian Republics, Afghanistan and Pakistan. Be alert for terrain issues especially during a diversion or depressurization situation. A review of the MEA, MORA, GRID MORA, and AMA along the particular route should be accomplished especially with reference to the ETOPS alternates. The terrain over Greenland is of significant importance in the event of a depressurization or diversion into a Greenland airport. Refer to the terrain information on Jeppesen publications. All Airindia B777 aircraft have not been modified to allow the use of the enhanced terrain warning and terrain display functions while operating in QFE mode and hence the TERR/OVRD switch will have to be selected to OVRD.
The TERR display will reflect a magenta area near and around the North Pole indicating unreliable / unknown terrain data with the FMC data base for those areas of the world. Depending upon the time of year and climatic conditions, the ice buildup over the polar region vary from 1000 to 3000+ ft. above sea level.

9.2 Area of Magnetic Unreliability (AMU)