Automatic
Takeoff and Landing
Automation of aircraft and
associated systems is advancing at a very fast rate. Technological advancements
have made it possible to incorporate significant upgrades to aerospace systems,
with new changes occurring frequently. One of these fascinating new capabilities
that have recently been utilized in both the commercial and military aviation
sectors is auto-land.
The Northrop Grumman Fire
Scout is one such military aircraft that has incorporated automation capability
into its landing phase on board U.S. Naval ships. The MQ-8C Fire Scout model is
the newest rendition of its Vertical Take-off and Landing (VTOL) Unmanned
Aerial Vehicle (UAV) line. The MQ-8C is based off of the Bell 407 helicopter,
which is bigger than its predecessor models which were based on the Schweitzer
333 (Naval-technology.com, n.d.). With
the increase in size, the MQ-8C brings an increase in systems capability as
well as increased payload. The data link, system control station, associated
hardware and software have had significant upgrades which will allow this UAV
to effectively carry out a wide range of operation missions while supporting a
wide array of capabilities for its Navy customer.
The Fire Scout utilizes a
UCARS system that provides positioning information for use in the automated
take-off and landing portions of flight. UCARS is composed of three major
subsystems:
·
The Airborne Subsystem (AS) providing a UAV point source for
precise position data
·
The Track Subsystem (TS), locating and tracking the UAV
relative to the chosen landing point. A motion sensing system is also employed.
·
The Recovery System (RS) provides guidance and control
functions utilizing the data link and provides for the human integration and
control interfaces within the system. Several launch, control and monitoring
functions are also completed by the recovery system (Ferrier, Sehgal, &
Ernst, 2014).
The UCARS system operates as
a “transponder based millimeter wave radar tracking system”, to track and provide
location and position inputs (Ferrier, Sehgal, & Ernst, 2014). The Fire
Scout does have safeguards in place allowing for manual landings and override
when needed, controlled via the data link in the ground control station.
A manned commercial aircraft that also has the
capability to autonomously land is the Boeing MD-11. The MD-11 incorporates
auto throttle control concurrently when its autopilot functions are
enabled. These systems “are completely
unified and essentially operate as a combined system until disengagement at
landing” (PMDG, 2010).
Auto land in initiated by
pushing the APPR/LAND button, and provided an ILS frequency is being utilized
that uses both a localizer and glide scope (automatically done by the Flight Management
System (FMS), the aircraft will auto land unless manually overridden. Autopilot
remains engaged after landing to ensure the aircraft remains aligned with the
runway, requiring disconnection following the end of the landing rollout (PMDG, 2010)
Three types of MD-11 auto land are identified below-
• “If
all your systems are operating normally you will see a green DUAL LAND
annunciation on the PFD FMA indicating a full CAT III auto land” (PMDG, 2010).
• “If
you have failures that are not critical for the auto land (for example, one of
the two autopilots inoperative or one HYD system failed) a white SINGLE LAND
will be annunciated and a CAT II auto land will apply” (PMDG, 2010).
• “If
you have critical system failures, or excessive deviation from LOC or GS a
white APPR ONLY will be annunciated and the auto land function will not be
available. The aircraft will continue to track LOC and GS, but autopilot will
disconnect at 100 ft AGL” (PMDG, 2010).
Crews of both aircraft have
to receive initial qualification training, as well as subsequent periodic
scheduled currency requirements.
References
Ferrier,
B., Sehgal, A., & Ernst, R. (2014). Retrieved from
http://www.auvsishow.org/auvsi2014/Custom/Handout/Speaker1851_Session767_1.pdf
Naval-technology.com.
(n.d.). Fire Scout VTUAV - Naval Technology. Retrieved from
http://www.naval-technology.com/projects/fire-scout-vtuav/
PMDG.
(2010, February 19). Tips for Boeing pilots learning the MD-11 - PMDG
Simulations. Retrieved from http://support.precisionmanuals.com/kb/a18/tips-for-boeing-pilots-learning-the-md-11.aspx
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