T6NL was (is) a major "Oh ****" caution in the Hawk (Adour) - I think.
"T6" meant excess Temp somewhere (presume point 6 in the engine). "NL" meant LP Fan overspeed - I think. "T6NL" meant one or the other - invariably the former, and therefore a surge / mech fail / not your day.
Tends to occur frequently in the Sim and Accident Reports. Fortunately for me, not in the aircraft...
OK for 16 years since I flew it ???