Airplane makers have always used a stranded core RG58. If you see a solid core one its because someone replaced it with "TV coax".
RG58 is smaller diameter and more flexible than RG400. For com & vor use with runs under 20 feet I can't see a problem. As for flammability, I'd bet half of the guys are running this RG400 through polyethylene conduit anyway.
Airplane makers have always used a stranded core RG58. If you see a solid core one its because someone replaced it with "TV coax".
RG58 is smaller diameter and more flexible than RG400. For com & vor use with runs under 20 feet I can't see a problem. As for flammability, I'd bet half of the guys are running this RG400 through polyethylene conduit anyway.
FYI: RG58u does have a solid center conductor variant though I doubt any certified aircraft would have ever used it....
I sincerely hope that no one is using "TV" coax. TV coax has an impedance of 75 ohm. Everything in you airplane uses 50 ohm cable.
Your avionics would not play well with "TV" coax.