Complex sentence: Its reluctance to be ignited required triethylborane (TEB) to be injected into the engine to ignite it, and to ignite the afterburner in flight; above -5 ° C TEB spontaneously ignites in contact with air.
Split into simpler sentences: Its reluctance to be ignited required triethylborane (TEB) to be injected into the engine to ignite it and the afterburner. Above -5 ° C, TEB spontaneously ignites in contact with air.