Home' RTCA Documents for Review : DO-201B User Requirements for Navigation Data Contents ED-77A/DO-201BforOpenConsultation/FRAC
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procedures are used by aircraft equipped with an FMS, which reduces the pilot workload
associated with ATC clearances and the transition between enroute and instrument
approach procedures. Enroute procedures are the segment of flight beginning at the
termination point of a departure procedure and ending at the origination point of the
approach procedure. Approach procedures or instrument approach procedures are
defined operations which begin at the approach to a landing.
Takeoff and Landing (TOLD)
The Takeoff and Landing (TOLD) functions in the FMS provide the pilot required
performance data related to takeoff and landing. The FMS uses takeoff or landing
runway information from the navigation database along with pilot-initialized
configuration settings and aircraft performance tables to compute data, such as V-
speeds and takeoff and landing distances. The data computed by the FMS is unique for
each aircraft type. Navigation data used by the TOLD functions includes but is not limited
to runway length, slope, direction, and elevation. Pilot-initialized configuration settings
and aircraft performance tables are not considered navigation data.
Performance computations are based upon initialization data, flight plan, and input from
aircraft systems that estimates the time enroute and fuel consumption for the flight plan.
The performance functions may also calculate the optimum speed and cruise altitude.
The performance function constructs the flight profile including the start of descent point
and the detailed descent profile. Speed target management is often a feature of the
performance computations. The performance computations are based on the flight plan
generated using the Navigation database.
Lateral and Vertical Navigation
Lateral navigation (LNAV) is function that computes and sends steering commands to
the flight controls system to laterally steer the aircraft. LNAV guides the aircraft along a
predetermined flightpath. Vertical navigation (VNAV) is a function that sends vertical
steering commands to the flight controls system for climb, cruise, or descent. The lateral
and vertical navigation functions control the aircraft to the flight plan generated using
the Navigation database. Additionally, the pilot can define lateral and vertical profile
information. Lateral and vertical navigation functions compute position uncertainty and
compares this against the required navigation performance of the procedure.
Runway safety is a top priority for the commercial aviation industry. A number of avionics
functions aimed at preventing runway excursions and incursions have been developed
which rely on navigation data. Most runway safety applications use runway and
approach information from a navigation database such as threshold locations,
elevations, glide path angle and crossing heights, and runway identifier, length, width
and azimuth, etc.
Many runway safety functions demand high accuracy database parameters, since they
often use information representing “geographic reality” (e.g .,
coordinates) and imprecision of the data could generate inconsistencies between the
aircraft physical location and function behavior. Furthermore, low aircraft speeds during
flight phases around the runway (i.e ., takeoff, landing, and taxi) requires accurate data
in order to ensure the function’s responsiveness.
Applications can provide enhanced approach planning tools, aural and visual runway
position awareness and alerting, stability guidance and alerting, and predicted runway
stop locations and overrun alerting. Example functions include overrun warning systems
defined in ED-xxx Minimum Operational Performance Specification (MOPS) for a
Runway Overrun Awareness and Alerting System, features providing 3D perspective
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