Complex sentence: In response, the pilots repeatedly increased power from the engines in order to maintain airspeed; seeing no improvement, they contacted the control tower in Ezeiza Airport and requested clearance to descend to a lower altitude.
Split into simpler sentences: In response, the pilots repeatedly increased power from the engines in order to maintain airspeed. Seeing no improvement in the aircraft's airspeed, the pilots then contacted the control tower in Ezeiza Airport and requested clearance to descend to a lower altitude.