These aren't T Mk1's - wrong nose shape and T1s can't use under wing fuel tanks as they don't have the internal pipework to connect to underwing tanks. Who are RAVN?
The word is Harbinger, not Harbringer. RAVN is RAVN Aerospace, based in Texas, which has a collection of small military jets and provides services to the US Dept of Defense. en.wikipedia.org/wiki/Ravn_Aerospace
