Complex sentence: The pilots did not act quickly enough on the brakes and proceeded to go full-throttle three seconds after touchdown, however they were unable to reach take-off speed because the 727's engines are slow-responding, taking about 6.6 seconds to power up.
Split into simpler sentences: The pilots did not act quickly enough on the brakes and proceeded to go full-throttle three seconds after touchdown. However, they were unable to reach take-off speed because the 727's engines are slow-responding, taking about 6.6 seconds to power up.