Equipment and materials

An area navigation system, RNAV, has dual way‐point selection for advance flight programming and tenth unit readouts for better navigation accuracy. Slant range corrected, linearised horizontal guidance circuits provide constant course widths regardless of distance from VOR stations. Course width (full scale needle deflection on course deviation indicator) is ±5 miles in the ENROUTE Mode and ±1·25 miles in the APPROACH Mode. Distance‐proportional, zero‐time‐lag filtering is included to provide instantaneous course deviation data in cross track manoeuvres.