The Northeast operation was with relatively early B727-100s as I remember. The B727-200 Advanced with increasing engine thrusts could have longer range - provided the runways were long enough. Some Scandinavian operators used them to the Canaries, while others maintained that the climb performance was so poor at very high weights that they got caught at low flight levels when they reached congested areas and that the Boeing 720B was a better aircraft for fuel burn and for keeping above most of the traffic. Antoin Daltun