Approach Navigation Option Displays and Procedures Dovetail With
Current and Emerging Technologies
Displays and Procedures
Are Similar to ILS
ILS remains the basic approach capability. To minimize training
requirements, new 737-600/-700/-800/-900 approach options use displays
and pilot procedures that are similar to those used with the ILS
(fig. B). For
example, the new options involve the established fly-to convention,
where a lateral pointer on the right of the center scale reference
indicates a lateral path to the right of the current aircraft position
displays include an explicit annunciation at the top of the attitude
indicator that clearly defines the source of the displayed deviation
scales and pointers. The approach data block, which includes the
selected station and course and distance measuring equipment distance,
is retained in the GLS and IAN approaches although modified to support
their unique characteristics.
procedures have been human engineered to ensure that, although their
appearance and operation are consistent with an ILS, aircrews easily
can differentiate among approach types (fig.
circumstances, pilots may choose to mix modes (fig.
D). For example, figure
E shows an Instrument Landing System localizer (ILS LOC) approach
with vertical navigation path (VNAV PTH) vertical guidance. The
procedures for mixed-mode approaches are straightforward, and the
display formats are consistent and easy to interpret.
Many airlines are moving away from the traditional dive and
drive step-down procedures and are introducing new constant-angle
nonprecision approaches (CANPA). In conjunction with the autopilot,
lateral navigation, and vertical navigation, CANPAs decrease workload
during approach by allowing the flight crew to load most required
data before beginning the approach.
The new 737-600/-700/-800/-900
navigation displays allow the flight crew to easily and intuitively
evaluate the status of the entire approach against an objective
flight technical error scale and pointer. Flight technical error
is a measure of the accuracy with which the airplane is being controlled
relative to the defined flight path. Deviations can be caused by
the autopilot, crew response to the flight directors, or external
environmental conditions such as a wind gradient or turbulence.