RNAV and RF Legs

RNAV Variability While making turns from one TF leg to another TF leg in an RNAV procedure, aircraft display a wide variety of track keeping performance. Aircraft speeds, winds, FMS logic and a variety of other factors contribute to these variances.

Recent demonstration of the wide variety of actual paths flown when transitioning from one TF leg to another. (Click image for larger view.) MITRE Corporation. Analysis of Advanced Flight Management Systems (FMSs), FMC Field Observations Trials by Al Herndon, Ralf Mayer, Randal Ottobre, Gregory Tennille, and Mike Cramer, 2006.

RNP Precision   Naverus RNP procedures use only curved RF legs for turns.  This ensures that aircraft maintain the same track keeping capabilities in turns that they do on straight TF legs.

Demonstration of aircraft track keeping ability in RNP RF turns. (Click image for larger view.)