Automatic Takeoff and Landing
A description
and analysis of some of the capabilities and limitations of two automated
systems during the takeoff and landing operations and their effects on safe
operations will be discussed in this paper.
First, I will outline some
of the functionality of the autopilot uses for the manned Airplane Boeing 737 takeoff
and landing. The performance is described below and this is done by the pilot manually
flying the airplane or by the pilot through the autopilot. The pilot
monitors the system which allow the position of the
plane before takeoff. If there is something wrong the pilot can des-engaged the
autopilot at any time, during the takeoff or while landing the aircraft.
Explanation on how the pilot or copilot operates the autopilot is described
below:
“The pilot can
monitor the airplane using the auto pilot and for airplane performance and
While monitoring the system receives
only an indication that, using maximum thrust, the airplane is still capable of
achieving a desired result, using scheduled thrust. Further, it does not
indicate where on the runway particular speeds are expected to occur or where
the airplane can be stopped from current position and speed”.
The
speeds are very important so at this level the pilot have to be aware of these
need it speeds, before the airplane is airborne. Also David said in the report
that;
“The main future of the system is an
airplane takeoff and landing performance monitoring system which utilizes
runway, ambient condition, flap setting, and airplane loading characteristic
information, input both manually and automatic maintain continuous
communication with the transducers to a computer, to generate acceleration for
predicting airplane performance during takeoff and landing”.
There is not clear
explanation on how the monitoring system controls the information with
automatic control. Looking to the way the pilot monitors before the takeoff roll,
David explain
“The take-off and landing performance
monitoring system provides the pilot with graphic and metric information to
assist in decisions related to achieving rotation speed (VR) within the safe
zone of the runway or stopping the aircraft on the runway after landing or take-off
abort. One-time inputs of ambient temperature, pressure altitude, runway wind,
airplane gross weight, center of gravity, selected flap and stabilizers setting
are utilized in generating a set of standard acceleration-performance data” (David B,
september 1991) .
Continually supervision
of this system is required by the pilot for complete verification of the
information gather from the computer. All Know data is very important as the report
said;
“We have to know Runway length available
for rotation, run way length available for stopping, an estimated runway
requirements of throttle position, engine pressure ratios, ground speed,
calibrated air speed, along-track acceleration, are used in computing engine
performance. A comparison of measured and predicted values is utilized in
detecting performance deficiencies. These comparisons and the runway length
computations lead to GO/ABORT signals. An important feature of the algorithm is
that the estimated runway rolling friction is updated based on measured
acceleration performance, resulting in more accurate predictions of future
performance. Airplane performance predictions also reflect changes in head wind
occurring as the takeoff roll progresses.” (David B, september 1991)
This
system is very reliable and demonstrates good performance in automation and
reducing cockpit work load and increasing safety considerably. It is very
important for the pilots to maintain the manual skill necessary for all stages
of flight. It is important for pilots to learn well how to timely troubleshoot
software or hardware problems. Such problems can degrade the system operations and
integrity variables. Runway contamination and wind shear are not easy to be
determined by the system and the pilots should exercise full awareness in this
situation for the safety of the flight.
The
second system to analyze is the UAV full Size Cypher UAV. System can be used for law enforcement in the private
sector. This UAV can be flown by using the conventional radio control hand set
or automatic functionality with system manager right and left displays with
supervision.
Operational
characteristics of the system are described as:
“The System safety
has been improved due to the shrouded blades. At the same time the design
concept provides improved hover and precision maneuver characteristics. The
flight control of the system is supervision, the operator directs the motion of
the platform, but does not fly it”.
We know that the
operator only act as an observer during this part. But the system
will be assisted
by the ground operator. As is explain by the report;
“ Supervisory
control allows the system to be operated by field personnel as a collateral
duty and does not require a dedicated operator pilot. The on-board flight
control system takes care of maintaining platform stability and coordinating
the controls to respond to operator direction”.
The sensor allow the UAV to fly to where
the mission is planned as Douglas state;
“The air mobility
platform was a shrouded rotor, VTOL UAV with a sensor suite mounted on top of
it The platform would fly to target location where it would autonomously land
and then conduct long term surveillance with its on board sensors. To reduce
communication power and time of communication the sensor data was processed on-board the platform by automatic motion detection software”.
It is necessary to know previously how many more
missions the system can
perform so the operator will performed the require
activities. The report said;
“At the end of the mission or when
surveillance was required in another location the system would be commanded to
restart, takeoff and go to the new location or return to its launch point. In the
ground control pilot interacts with the system thru the System Manager display that
is split into two portions. The left side displays a digital map of the area of
interest, and the right displays the payload sensor output to plan a mission
the operator selects the route/destination way-points or areas to be searched
using a mouse. Route planning software then plans a safe route to select the way-points or search areas”.
These two displayed monitors help the operator
to operate the UAV auto pilot for takeoff cruise and landing all is done through
the system manager. Douglas is ending by saying;
“The proposed
route is displayed to the operator for acceptance. Soft buttons for control of
aircraft functions, such as; auto takeoff, cruise, search, etc., are also
displayed on the bottom portion of the System Manager screen. The right side of
the System Manager display shows real-time data from the onboard sensor. This
data includes full video or FLIR imagery. Data from the FUR can be analyzed by
an Automatic Target Recognition system to detect targets and provides target
location information back to the System Manager. Aircraft and target position
along with track history are displayed on the digital map.” (Douglas
Murphy, November 1998.)
Some considerations are very important in this
system. This system can be operated manually and automatically. The Cypher UAV
can also be used for local missions and commercial applications. However,
safety could be degraded in the event of software corruption during the takeoff
or landing or during the mission. In the event that the operator made a mistake programming this system, there is no clear way to detect it. The problem would
be that there is only one operator whom interacts directly with the UAV. The shrouded
blades are a very important safety issue, therefore more simulation and fly
hours are necessary to comply with the safe standards required from the FAA to gain
public confidence for integration of this system in to NAS.
These
two systems show the advance technology for operation of automatic systems with
sophisticated autonomy. Only time and experience using these systems will let
the manufactures and the engineering industry learn and correct any computer glitches
software, hardware related problems and operational deficiencies of these
systems.
References
David
B, R. S. (September 1991). Airplane Take Off and Landing Performance
Monitoring Systems.
Douglas Murphy, J.
C. (November 1998.). Applications for mini VTOL UAV for Law Enforcement.
