Paper for the Digital Avionics Systems Conference (DASC) 2011

1. 1
ENHANCING PILOT ABILITY TO PERFORM CDA
WITH DESCRIPTIVE WAYPOINTS
Michael LaMarr & Dr. Nhut Ho, California State University Northridge, California
Dr. Walter Johnson & Vernol Battiste, NASA Ames, Moffett Field, California
Joe Biviano, Lockheed Martin, Palmdale, California
Abstract
Aircraft noise is a burden on people living
around airports and is an impediment to the growth of
air transportation. Continuous Descent Approach
(CDA) is an approach that reduces noise impact on
the ground by keeping the aircraft at a higher altitude
longer than standard approaches and by keeping
engines idle or near idle. However, CDA
implementation requires controllers to add large
separation buffers between aircraft because aircraft of
different sizes and weights descend at different rates,
consequently creating uncertainty in separation
between aircraft. This paper proposes a viable near-
term solution to allow pilots perform CDA more
consistently through the use of Descriptive
Waypoints (DWs), or checkpoints in terms of
altitudes and speeds along the CDA path that provide
the pilot targets and feedback along the CDA path. A
human in the loop study was conducted to develop
and determine the effectiveness of using DWs to
improve flight performance during CDA procedures,
and provide recommendations on DW design and
integration into existing CDA procedures.
Twelve instrument rated commercial pilots flew
three different wind conditions using one, three, or
five DWs. Dependent variables included: deviation
from DW target altitude and Indicated Airspeed
(IAS), average power usage, perceived workload, and
pilot acceptance of DWs. Objective and subjective
data were also collected to obtain pilot feedback on
the design of DWs and their integration into CDA
procedures, and determine pilot strategies while
flying CDA with DWs.
The results showed that as the number of DW
increases, mean altitude deviations from the DW
targets decreased from 922 feet to 196 feet and
standard deviations from 571 feet to 239 feet with a
slight increase in perceived workload and one percent
increase in power usage and. The pilots commented
that the DWs provide useful feedback to strategize
how to make corrections to the altitude deviation in
the vertical path, and that they would feel
comfortable having the DW integrated in the flight
chart or shown as a vertical view on a display. The
pilots also provided a number of recommendations
for integrating the DW into Jeppesen charts and roles
for the pilot flying and the pilot not flying.
These results imply that DWs can be used as an
effective cuing system to enhance pilot ability to
perform CDA, and that they are a potential choice for
near to midterm implementation in improving the
effectiveness of CDA procedures.
Background
Continuous Descent Approach Benefits
Noise and emissions produced by aircraft when
landing are a burden on people living around airports
and is an impediment to the growth of air
transportation. The produced noise limits how many
aircraft can land at night and the ability to expand
more runways or build new airports in populated
areas. Currently, aircraft descend and land at
different speeds based on their size and weight,
making it difficult to predict their future trajectory.
Air Traffic Controllers (ATC) compensate for
dissimilar aircraft performance by creating an
approach pattern in which all aircraft fly time-
consuming and fuel-burning stair-step flight
segments at the same speeds as they enter the
terminal area [1,2,3]. This practice makes it
manageable for the ATC to separate aircraft;
however, it creates a significant noise impact on the
local community. The noise is most profound in
areas where the aircraft have to fly at low altitudes

2. 2
near the runway because of the existing navigation
constraints. Specifically, aircraft land by using an
instrument landing system (ILS) glide slope to
intercept the glide path at the correct descent angle to
the runway (see figure 1). The ILS provides the pilot
with lateral and vertical guidance to maintain the
correct approach orientation for landing. This is
accomplished by leveling off at an altitude that
allows the aircraft to intercept the glide slope from
below. If the aircraft flies above the glide slope it
may intercept a false glide slope and come into the
Figure 1: Conventional Approach and Continuous Descent Approach
airport at an incorrect landing angle. To operate
within the navigation constraints of the ILS and
reduce noise impact, noise abatement approach
procedures have been developed and implemented.
One such procedure is Continuous Descent Approach
(CDA). CDA also offers other benefits such as fuel
savings and lower emissions impact by using an idle
or near idle power and by decelerating the aircraft at
a higher altitude longer than the standard landing
procedure without reverting to level flights (See
Figure 1). The benefits of CDA have shown in many
studies and demonstrations, such as the CDA flight
demonstration study conducted in Louisville,
Kentucky with UPS Boeing 767-300 aircraft
equipped with the Pegasus flight management system
(FMS) [4]. It was shown that CDA can reduce noise
by 3.5 to 6.5 dBA (3 dBA is noticeable to the ear)
and fuel consumption by 400 to 500 pounds.
CDA Implementation Challenges & Current
Work on Improving Performance Predictability
Currently implementation of CDA is not
practical in moderate to high traffic because it
requires a larger separation buffer between aircraft
than the standard landing procedure. Predicting
where the aircraft will be is cognitively taxing on the
controller and pilots because deceleration is non-
linear and humans have a difficult time judging non-
linear deceleration when speeds are constantly
changing [3, 5]. To implement CDA, ATC have to
know when aircraft are at the right distance from the
airport to initiate the clearance to start the descent. If
the air traffic controller tells the pilot to initiate CDA
too early, then the aircraft will arrive before the
runway and will have to level out before landing.
Leveling out early requires power increase, which in
turn creates more noise and defeats the purpose of the
procedure. If the ATC tells the pilot to initiate the
procedure too late, then the pilot will end up making
a fast landing or have to initiate a go-around for
another approach (which produces more noise and
uses more fuel, which also defeats the purpose of the
CDA).
To assist ATC in managing CDA, ground based
automation is being developed. Stell et al is working
on an algorithm for ground based automation called
Three-Dimensional Path Arrival Management
(3DPAM) to provide top of descent (TOD)
prediction to controllers [6]. The purpose of this
algorithm is to predict TOD location within a
tolerance of 5 nm to help controllers manage CDA
traffic. This algorithm takes into account that even
with a perfect TOD predictor the vertical profiles and
path distance must be predicted accurately as well.
Kuper et al conducted a study with three
different ground based support tools for ATC to work
Airport
Continuous
Descent Approach
Conventional
Approach
10,000
feet
4,000 feet
ILS Glide Slope

3. 3
in Super Density Operations (SDO) environment [7].
These tools are timeline, slot marker, and speed
advisory. Timeline gives the ATC estimated time of
arrival (ETA), slot marker gives a visual
representation (circle) to the ATC where the aircraft
should be if on schedule, and the speed advisory
provides controllers with air speed advisories that can
be used to correct scheduling errors. Based on
subjective feedback, ATC preferred the slot marker
tool.
Alam proposed that dynamic CDA would allow
the FMS to create unique CDA routes based on
aircraft type, size, and weight [8]. But in order for
dynamic CDA to be implemented ATC will need to
have the same information as the pilot. This can be
accomplished with real time data linking between
controllers and pilots with controller pilot data link
communications (CPDLC). The controller would be
able to uplink the flight plan to the FMS to initiate
CDA, and the pilot would then send the executed
FMS CDA route back to the controller.
Ren and Clarke developed the Tool for the
Analysis of Separation and Throughput (TASAT) to
predict trajectories of different aircraft performing
CDA and to determine the minimum spacing at a
metering point in order to avoid separation violations
[9]. Factors that contribute to aircraft trajectory
variations are aircraft type and weight, FMS logic,
and pilot technique and winds.
Other challenges to the implementation of CDA
procedures remain the difficulty that pilots have in
managing the deceleration of aircraft in the presence
of uncertainties in pilot response time, vertical
navigation performance (VNAV - controls vertical
automation of aircraft according to flight profile
programmed in the FMS), and wind conditions [10].
Koeslag also identified other issues with current
CDAs [11]. One issue is how the vertical flight
profile is managed and depends on the type of FMS
installed. Another issue is that wind can cause the
aircraft to deviate from the FMS-predicted flight
trajectory. One of Koeslag’s proposed solutions was
to have a fixed CDA vertical profile to improve
arrival time predictability and add flap guidance in
the primary flight display (PFD) to correct for speed
deviations (see Figure 2).
Figure 2: Flap Cues Recommended by Koeslag in
Primary Flight Display [11]
Other research efforts aiming to make CDA
more predictable are focusing on equipping FMS
with 4D guidance (x, y, z, and time). Moore
proposed 4D information with a required time of
arrival (RTA) to aid ATC in establishing a strategic
time scale of CDA traffic flow [12]. The algorithms
designed in this research are aimed to minimize time,
fuel, and emissions produced. One problem noted is
that automation can cause the VNAV to make
occasional thrust changes that can generate extra
noise and fuel usage.
Other research on RTA during CDA operation
proposed to provide pilots with an energy
management system (see Figure 3) in the navigation
display to minimize fuel, noise, and emissions. The
system provides pilots an optimal vertical path with
energy events and energy error cues for managing
throttle and drag [13].
Figure 3: Energy Management System used by
NASA Langley Research Center

4. 4
Other flight demonstration studies found that
pilot delay in initiating the flaps had undesired effects
on VNAV in that it causes the aircraft to deviate from
the altitude programed on the FMS [4]. Another
problem identified with the VNAV is that when
descending, the VNAV’s logic gives the altitude
constraint higher priority than the speed constraint.
With factors such as tail wind, the aircraft does not
always meet the speed targets. It is important to meet
both the speed and altitude constraints on the flight
path for fuel and time efficiency, and for traffic
separation.
Development of Descriptive Waypoint
These studies have been beneficial to CDA
research and development, but are aiming for mid to
long term implementation; until better VNAV logics
and FMS designs can compensate for pilot delay,
altitude and speed constraints, and wind
uncertainties, the pilot has to control the vertical
profile manually. If pilots have information to help
them stay on the flight path and manage their
aircraft’s speed, CDA would be more feasible for
daily use. One way to aid pilots in executing CDA is
to give them feedback information. Without the help
of a cuing system, pilots find it difficult to manage
the aircraft energy to meet a target speed at a specific
altitude in the presence of uncertainty. According to
Ho et al, there are two reasons for uncertainty during
CDA [3]. One reason is the pilot’s inability to
estimate future position of aircraft because the
deceleration profile is non-linear. The second reason
is that the pilot’s projection may be incorrect because
of wind uncertainty. They proposed to provide pilot
feedback info in terms of gates, which are an altitude
and speed target along the flight path. For
consistency purpose, gates will be called Descriptive
Waypoints (DW) in this paper. In Ho’s study,
different numbers of gate conditions (0, 1, 2, and 3)
were proposed to use with a flap schedule. Each of
these conditions also had wind uncertainty and no
wind uncertainty. For the two DW condition, the
DWs were located at 5000 and 3000 feet from the
runway, and the three DW condition had DWs at
5000, 4140, and 3000 feet (see Figure 4). The DWs
were given to pilots on a cue card shown in Figure 4.
Providing vertical information and DW at 7,000 feet
altitude improved pilot ability to perform CDA. In
the three DW condition, pilots were able to achieve
the target speed at a higher rate than the other
conditions.
Figure 4: DW Cues with Flap, Altitude and
Indicated Air Speed References [3]
Given that CDA is being considered to be
initiated at further distances from the airport (e.g.,
such as 37,000 to 40,000) for fuel savings and
emissions reduction, the concept of DW was
conceived and formulated as an extension of the gate
concept [14]. The name DW was chosen because
dynamic waypoints (target altitude and speed
waypoints that can be created in real time, relying on
the existing waypoint database) focus on providing
updated waypoint information, and DW is a
description of a waypoint that could include a time
target, flap requirement, gear deployment, target
altitude, and speed. For this study, only altitude and
Indicated Air Speed (IAS) was provided in the DW.
Flap information was displayed in the PFD.
Display of Descriptive Waypoints
With the description of DW defined, it is
important to examine how to display the DW
information to the pilot. The navigation display (see
Figure 5) is a useful way of informing the pilot of the
general surroundings, and is currently limited to a 2D
perspective.

5. 5
Figure 5: 2D Navigation Display
Pilots also use arrival charts when they are on
their final approach, with the vertical information
(altitude) displayed as text as in the 2D navigation
display, as well. Figure 6 represents the vertical
profile the pilot needs to fly with the step down fixes
to intercept the glide slope and land.
Figure 6: Flight Chart Final Approach [15]
Thomas and Wickens found that it is easier to
make specific and accurate judgments based on
absolute spatial information displayed in 2D with 3D
information [16]. This is because 3D displays tend to
make the x, y, and z axis ambiguous, whereas 2D
information gives precise x and y information, but
will need the 3D information in text. There is also a
problem that occurs while using 3D views: without
other depth cues available, the location of objects
become ambiguous [17]. Even with this problem 3D
views do have their advantages. For example, shape
understanding is beneficial in 3D, whereas 2D is
more accurate for precision tasks [18]. For the
current study with a focus on implementation in the
near term, it makes sense to display the DWs to pilots
in 2D because pilots are only controlling their
vertical descent during CDA.
Implementation of DWs into the current flight
deck system can be accomplished by displaying them
in a vertical flight chart (see Figure 7). Vertical flight
charts typically display the final approach right
before the glide slope at approximately 3,000 to
10,000 feet altitude. The initial altitude in the
current study starts at 23,000 feet altitude at 70 miles
from the airport. This is motivated by the fact that
CDA procedures are being proposed to start at a very
far distance from the airport, such as the top of
descent location, which is typically at 37,000 to
40,000ft [14].

6. 6
Figure 7: Three Descriptive Waypoints
A possible solution for midterm to long term
implementation is to use a coplanar view (horizontal
and vertical profiles) of the navigation with DW
information. The vertical display would benefit
pilots, enabling them to monitor the vertical profile
when VNAV is turned off and the pilot is manually
flying the vertical profile (see Figure 8).
Figure 8: Coplanar Navigation View [19]
Another possible long term solution that can
help the pilot perform CDA more efficiently is to
display DWs in the Cockpit Situation Display (CSD)
to provide 3D visualization of the flight plan (see
Figure 9) [20]. CSD is a navigation aid that pilots
can use to gain information of surrounding air traffic,
alert them of possible conflicts, provide spacing
tools, etc. CSD eliminates 3D ambiguities by
allowing the pilot to rotate the screen 360 degrees
and switch to 2D anytime.
Figure 9: 3D Cockpit Situation Display
The current study is an extension of Ho’s gate
study of adding predictability to the pilot during
CDA. VNAV was set to off because it was shown to
affect CDA performance in previous studies. LNAV
was left on auto-pilot

7. 7
Method
Design
A 3 wind (Fast, Normal, and Slow) x 3 DW
(One, Three, and Five) within-subject factorial design
was used. The wind conditions (Fast, Normal, and
Slow) were based on historical data at Louisville
International Airport and were chosen to produce
noticeable differences. In the Fast wind condition, the
wind speed started at 52.8 knots (60% higher than the
normal wind condition), the Normal wind condition
had a starting wind speed of 33 knots, and the Slow
wind condition had a starting speed of 19.8 knots
(40% lower than the normal wind condition) (see
Figure 10). The One-DW, Three-DW and Five-DW
conditions provided the pilots with one, three, and
five DWs respectively along the CDA path (see
Figures 12-14). The number of DWs was designed to
vary the amount of feedback provided to the pilots.
Dependent variables included: altitude and IAS
deviation, computed as the absolute deviation from
DW target altitude and IAS. Altitude deviations and
IAS deviations are metrics used to evaluate how
DWs assist pilots to maintain the CDA flight profile.
Power percentage usage was computed as the average
power the aircraft uses during the CDA. Perceived
workload, pilot acceptance of DW, pilot strategies
and other subjective data were collected in a
questionnaire (rating scales and open ended
questions) to evaluate the effectiveness of DW and
obtain feedback on pilot acceptance and the
integration of DW into existing CDA procedures.
Figure 10: Wind Speed
Material
Stimuli were displayed on two 19” monitors,
with one monitor running the Multi Aircraft Control
Station (MACS) software which provides a dynamic
interface that allows the pilot to fly and interact with
the aircraft’s systems, such as IAS, vertical speed,
flap settings, and altitude [21]. The other monitor
was running Cockpit Situation Display (CSD) which
was used to display the CDA flight plan on a 2D
fixed vertical view (see Figure 11) [20]. Depending
on the condition, the DWs were displayed on a flight
chart as one, three, and five DWs as shown in Figures
12-14. The CDA profile used in the current study
was developed and verified by NASA in a previous
study [20, 21]. Modifications were made to the CDA
profile by creating aircraft start and end points,
removing all traffic, and by adding DW locations
with considerations for the aircraft’s kinetic and
potential energy, noise, deceleration, speed/altitude
targets, and power usage. The CDA profile flew is
the same in all conditions.
Figure 11: MACS (top picture) and Cockpit
Situation Display (bottom picture)
0
10
20
30
40
50
60
0 20000
Altitude, [ft]
Fast
Wind
Normal
Wind
Slow
Wind
WindSpeed,[knots]

8. 8
Figure 12: One Descriptive Waypoint Condition
Figure 13: Three Descriptive Waypoints Condition
Figure 14: Five Descriptive Waypoints Condition

9. 9
Facilities
The study was conducted in the Systems
Engineering Research Laboratory at California State
University Northridge (see Figure 15). Pilots were in
a room with a one-way mirror and sat at a desk with
two computer monitors and a flight chart, and used a
mouse to interact with the monitors.
Figure 15: Pilot Station Setup
Participants
Participants included twelve instrument-rated,
commercial pilots (11 male, 1 female) between the
ages of 24 and 67 (Mean 37.64 years old) with years
of flying between 2 and 37 years (Mean 18.75 years)
and with 590 to 23,000 (Mean 7660) hours of flight
time. Two pilots have experience with CDA, and one
has experience with CDA simulation.
Results
Altitude and IAS deviations and average power
were collected from MACS output and put into excel
for each participant for nine conditions. Data was
organized by dependent variable, and a 3x3 (Wind x
DW) analysis of variance (ANOVA) was run on
SPSS version 17 for each of the dependent variables.
Attitude and IAS Deviation
Figure 16 shows the means and standard
deviations of altitude deviations at the DW targets 1
through 5. There was a significant main effect of
DW on altitude deviation on DW targets 2 through 4,
F(1.392, 15.308)= 26.364, p<0.000, etap
2
=1.000 and
no significant main effect of Wind on average
altitude deviation on DW targets 2 through 4. In the
Five-DW condition, (mean=196.06 sd=238.90)
significant differences in average altitude deviation
were found compared to the Three-DW condition
(mean=516.00 sd=287.68) and the One-DW
condition (mean=922.32 sd=570.61). The difference
in altitude deviation between the Five-DW and
Three- DW condition was 319.94 feet, between the
Three-DW and One-DW condition was 406.32 feet,
and between the Five-DW and One-DW condition
was 726.26 feet. There was no significant interaction
effect between DW and Wind on altitude deviation of
DW targets 2 through 4. There were no main
effects or interactions with IAS.
Figure 16: Average Altitude Deviation Main effect on DW
0
200
400
600
800
1000
1200
1400
1600
18nm to Cheri:
DW Target 1
Cheri:
DW Target 2
Alt<10:
DW Target 3
10nm to SDF:
DW Target 4
5nm to SDF:
DW Target 5
1 DW
Condition
3 DW
Condition
5 DW
Condition
AltitudeDeviation,[Ft]

10. 10
Power Usage
There was a significant main effect of DW on
average power percentage, F(1.928, 21.203) = 3.731,
p<0.042, η=0.609, and no significant main effect of
Wind on average power percentage. In the One-DW
condition, (mean=7.25 sd=2.31) significant
differences of average power percentage were found
compared to the Three-DW condition (mean=7.62
sd=2.39) and the Five- DW condition (mean=8.35
sd=3.45). The difference in average power
percentage between the One-DW and Three- DW
conditions was .37, between the Three-DW and Five-
DW conditions was .73 average power, and between
the Five-DW and One-DW conditions was 1.1.
There was no significant interaction effect between
DW and Wind on average power percentage. Figure
17 shows the mean power for different DW
conditions.
Figure 17: Average Power Main effect on DW
Subjective Data and Feedback
Pilot Strategies and Feedback on DW Design
The majority (10 out of 12) of the pilots
commented that they used the altitude and speed
deviations at the DWs as feedback to manage the
descent. Specifically they strategized that when
coming in too fast to a DW target they would reduce
vertical speed, and when coming in too slow to a DW
target they would increase vertical speed. This
strategy was used in combination with their rule
thumb for managing vertical speed, which is for
every three miles the aircraft descends 1,000 feet.
They also reported using the speed brakes as little as
possible and using the flaps only as needed.
In terms of the placement of the DWs, the pilots
mentioned that they like the spacing between each
DW target and how the 10,000 feet level off section
(Alt<10: DW Target 3) helped slow down the
aircraft. One pilot said that it was difficult for him to
slow down at 10,000 feet from 240 IAS to 160 IAS
until the end of the scenario because of the workload
of using the speed brakes and setting the flaps. They
recommended that the distance between two DWs be
between 10nm to 30nm apart when they are further
away the airport, and 5nm to 10nm when precision
flight is needed closer to airport. Overall, the mean
for pilot rating of the effectiveness of the DW target
locations on the flight plan were 4.67 out of six
(where 1 is very uncomfortable and 6 is very
comfortable).
In terms of power management, the pilots stated
that DW helps reduce power usage of the aircraft if
the descent was planned correctly to intercept DW
altitude without leveling out. If the aircraft is early to
the target altitude before DW target, it creates level
off altitude segments, which increases power usage.
Pilots commented that with the green arc (altitude
prediction tool) in their NAV display, they would get
to the DW altitude target without leveling off.
Perceived Workload
The results from a 3x1 (DW x Wind) within-
subject analysis of variance (ANOVA) revealed a
significant main effect of DW on perceived
workload, F(1.496, 16.451)=77, p<0.000,
etap
2
=1.000. In the one DW condition, (mean=2.58
sd=0.67) significant differences in workload were
found compared to the three DW condition
(mean=3.25 sd=0.75) and the five DW condition
(mean=4.17 sd=0.72). The difference between the
one three DW condition was 0.67 perceived
workload, between the three one DW condition was
0.92 perceived workload, and between the five DW
and one DW condition was 1.59 perceived workload.
Figure 18 shows the mean workload for each DW
condition. A likert scale was used to assess workload
(where 1 is very low and 6 is very high).
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
1 DW 3 DW 5 DW
AveragePowerPercentage

11. 11
Figure 18: Average Perceived Workload Main
effect on DW
Feedback on Flight Chart, Vertical View on
CSD , and CDA scenarios
The pilots rated the usefulness of a using a
vertical flight chart integrated with DW information
with a mean score of 4.42 out of 6 with a standard
deviation (SD) of 1. Most pilots liked the provided
DW flight chart, and commented that they would like
the DW information much better if used in
combination with the Jeppesen chart, and preferred to
have the distance to next DW and descent angles
(based on ground speeds) be inserted into DW flight
chart.
In terms of the utility of the vertical view on the
CSD for maintaining the flight plan, the pilots rated
its usefulness with a mean score of 3.75 out of 6 with
a SD of 1.22. They suggested a number of additional
features and information to be added to the CSD,
including thicker flight path, known vertical
deviation from flight path, a green arc ("banana" for
altitude confirmation), and an option to zoom in and
out. A Boeing 757 pilot said that his cockpit setup
(vertical NAV screen is next to the regular NAV
screen on the right) is similar to what was done in the
study and has an energy management arrow (similar
to Figure 3) which is helpful for flying CDA.
For the CDA scenario designed in the study, the
pilots thought that scenarios were realistic and that
they would have flown better with the help of a pilot
monitoring (PM) and with tools such as the green arc.
They suggested that the roles of the pilot flying (PF)
would be able to fly vertical speed and IAS, make
decisions for meeting DWs, and vocalize plan and
callouts to the PM. As for the roles of the PM, they
suggested that the PM monitor targets, air speed,
IAS, and DWs; do all calculations for the PF; set
altitudes, MCP; work the gear and flaps; crosscheck
altitude inputs; and communicate with ATC.
Conclusions
In this paper, descriptive waypoints were
proposed as a viable near-term method to assist pilots
in performing CDA procedures that start further away
from the airport than CDAs used in current practice.
It was hypothesized that the pilot performance would
improve as the number the descriptive waypoint
increases, and the results in the experiment
corroborate this notion. As indicated in the
experimental results and pilot feedback, the
descriptive waypoints act as a feedback mechanism
that help “reset” the system by allowing the pilots to
make adjustments based on the altitude deviations
from the targets at the descriptive waypoints. The
Five-DW condition (the condition with the most
number of descriptive waypoints) resulted in only
one percent more in power than the other conditions
and with a slight increase in workload. With
automated assistance (such as the green arc), the
pilots believed that they would use less power by
intercepting the DW altitude target without resorting
to level flight. The potential small increase in
workload could be addressed by developing
procedures that assign the pilot monitoring the task of
monitoring the deviations at the DW targets and
vocalizing plans to meet the next targets.
In combination, proper design of the descriptive
waypoints’ locations and targets and of the
approach’s vertical and speed profiles allowed pilots
to fly the approach consistently, which will help ATC
with aircraft separation and ultimately make CDA
more feasible in high traffic conditions. For future
development, the DWs can be implemented into the
current flight charts for near term implementation,
and for midterm, they can integrated into more
advanced software that would provide power
management and dynamically update DW altitude
and IAS targets based on wind speed and constraints
on arrival time.
0
1
2
3
4
5
1 DW 3 DW 5 DW
AveragePerceivedWorkload

12. 12
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