Complex sentence: At he began to descend and with little control and no means of slowing the fighter down, he could not execute a safe landing and too badly injured to parachute to safety Lock was in a perilous situation.
Split into simpler sentences: At he began to descend and with little control and no means of slowing the fighter down, he could not execute a safe landing. Too badly injured to parachute to safety Lock was in a perilous situation.