"Jet fuel, also known as kerosene, could never accomplish this phenomenon--if it could, then it would obviously melt the steel jet engines that burn it for fuel."

Bull. Your "what if" is total crap. The change in temperature of any object can be found knowing 1) heat input into, 2) heat output from, and 3) heat capacity of the object. It is well known that the physical propterties of metals can change drastically with changes in temperature. Knowing the consequences of high temps., nearly every combustion engine that is worth the fuel put in it relies on dumping heat to the environment. If cooling is lost and the system is still put under load, damage can occur.

Most jet engines out there are high-bypass, meaning a large, if not majority, portion of the air taken into the engine bypasses the combustion stage. The engine is cooled by this bypassed air. I don't believe that jet fuel burns hot enough (since the heat input is a function of difference in temperature between the fuel and the engine) to melt the engine, but high temps (meaning above spec) with high loads will lead to engine failure.

Jet fuel burning in a building isn't a comparable scenario to it burning in a jet engine. It is not "obvious." It is easily conceivable that metal supports with no real cooling system could reach much higher temperatures than a cooled engine, both burning the same fuel. Furthermore, I'd bet my next paycheck you could expose one side of a metal specimen to a temperature higher than its melting point, while cooling the other side and have nothing other than superficial melting on the specimen, if any at all!

Jet engines also frequently use different materials for the hot parts of the engine than for the cooler parts.

What did we learn? That the temperature of the combusting material is only one part of the "how hot does it get" equation. [For more complete exploration, expand this to take into account time-variance, and if doing so, the conductive ability of the material.]