Description and flight performance of two systems for two-segment approach

This paper describes two different avionic systems which were designed and developed to provide guidance and control for two-segment noise abatement approaches. The concept of a low-cost retrofit avionic system evolved into a special-purpose two-segment computer which required a DME collocated with the ILS glide-slope transmitter. This system was evaluated in a Boeing 727-200 aircraft. The second system is an area navigation (RNAV) system modified to include the two-segment approach. This system is more sophisticated than the first system and does not restrict usage to any specific navigation ground aid. The modified RNAV system is a Collins ANS-70A and is currently being evaluated in a DC-8-61 aircraft.