Question-Do fighters use HF Comms during coronet type flights or tanker assisted transoceanic flights in order to contact the HF ARTCC controllers?
They let the tankers handle the ATC & mission-following stuff when over the ocean. Fighter pilots usually don't give the cargo aircraft ("trash haulers") much respect until that tiny little fighter is flying over the huge ocean. Then they want to stay REAL CLOSE to the tanker.
In the old days, the fighters used to be escorted by a special EC-135K which used the callword/mission-name HEADDANCER. It was usually # 55-3118, which had a tremendous history to it -- the very first KC-135A produced, only one to do a barrel-roll (Boeing test pilot "Tex" Johnson), converted to an EC-135 & used for many years as the USAF Tactical Air Command Airborne Command Post based at Seymour-Johnson AFB, then converted to EC-135K & was one of two used by the 8th Tactical Deployment Control Squadron, doing the HEAD DANCER mission & TAC ABNCP until TAC went away. Right now, she's resting back in KC-135 attire as the 'gate guard' at McConnell AFB.
OK, sorry, went into one of my usual strategic C3,I history rants...
This plane would do the ARs plus handle long-range comms for the fighters it was escorting, and HEADDANCER had the capability to patch the UHF air/air channel they were using with the fighters onto HF/SSB. Sometimes the HEADDANCER radio op would ask for a phone patch for the fighter, other times they'd just activate the UHF<-->HF link & the fighter would call MAINSAIL (any ground station) & ask for the patch themselves. This would sometimes confuse me, as I'd be hearing a callsign I knew to be associated with a fighter-type aircraft that didn't normally have HF, and a pilot who didn't seem versed in HF procedures.
In the real old days, USAF Tactical Air Command had their own HF/SSB Command & Control network, known as the FIRESIDE net. It was phased-out probably close to 30 years ago now & I only heard it active a few times before it went away.
These days, pretty much any KC-135 or KC-10 can do it, but if I recall right, some squadrons/tanker task force aircraft that do the fighter escort mission a lot have a special comms suite.