Category IIIB Autoland, Global Navigation Satellite System
Landing System, Integrated Approach Navigation, and Navigation
Performance Scales options work together or separately to
improve safety and performance while decreasing operating
Operators will be able
to enhance the approach capability of their 737-600/-700/-800/-900
airplanes this year with a suite of new flight deck navigation options:
Category IIIB Autoland, the Global Navigation Satellite System (GNSS)
Landing System, Integrated Approach Navigation, and Navigation Performance
Together with the excellent
existing approach capabilities
of the 737, these options offer a flexible navigation solution for
airlines that want to increase their competitive advantage by improving
airplane safety and performance, decreasing operating costs, and
reducing flight crew training requirements through advanced technology.
The new navigation options
work together or separately to enable pilots to fly safe, stable,
and precise three-dimensional paths that smoothly intercept a variety
of final approach legs.
The options improve landing
capability in adverse weather conditions, in areas of difficult
terrain, and on existing difficult approach paths. It addition,
they will allow crews to take advantage of emerging air traffic
control technologies designed to improve airport operations.
To help operators understand
these navigation options and their features, this article describes
The article also discusses
how the options and procedures are compatible with current and emerging
approach navigation technologies such as the Instrument Landing
System, mixed-mode, and constant-angle nonprecision approaches.
CATEGORY IIIB AUTOLAND
The new 737-700/-800/-900
Category IIIB Autoland option (fig.
1) provides the same all-weather, precision approach autopilot
guidance currently available on other Boeing airplane models.
This option, which is
in flight test, will be offered with the 737-700/-800/-900 over-under
engine format. The over-under format provides the display space
necessary for Category IIIB Autoland system messages. (The 737-600
is not currently being certified for Category IIIB operation.).
GNSS LANDING SYSTEM
GNSS Landing System (GLS) option uses Global Positioning System
navigation satellites and a Ground-Based Augmentation System (GBAS)
to provide signals similar to Instrument Landing System (ILS) signals
(fig. 2). Ultimately,
the GLS could replace the ILS as the primary means for guiding airplanes
to the runway in low visibility. The GLS also might be expanded
to support curved approaches. (See Global
Navigation Satellite System Landing System, Aero no. 21,
The initial 737-600/-700/-800/-900
GLS option supports a Category I instrument approach capability
and the ability to complete the approach with an automatic landing.
This system is being expanded to support full Category IIIB Autoland
Retrofit for the 737-600/-700/-800/-900
GLS requires new multimode receiver (MMR) hardware and software,
a navigation control panel with GLS capability, hardware and software
upgrades for the enhanced ground proximity warning system (EGPWS),
flight management computer (FMC) U10.5 software, and common display
system (CDS) Block Point 2002 software. A future curved GLS approach
capability might require autopilot and CDS software changes.
The U.S. Federal Aviation
Administration (FAA) plans to deploy GLS ground stations in Memphis,
Chicago OHare, Juneau Alaska, Seattle, Phoenix, and Houston
to support operational evaluation testing. The program calls for
the purchase and deployment of as many as 40 ground stations per
year after the initial phase. The FAA projects a total of 160 GBAS
ground stations are needed in the United States. Europe also plans
to develop and install GBAS ground stations.
INTEGRATED APPROACH NAVIGATION
Integrated Approach Navigation
(IAN) is an approach option designed for airlines that want to use
ILS-like pilot procedures, display features, and autopilot control
laws for nonprecision (Category I) approaches. This option does
not require additional ground facility support.