This document summarizes research on using descriptive waypoints to help pilots perform continuous descent approaches more accurately. It describes a study that tested different numbers of descriptive waypoints under varying wind conditions. The results showed that using five descriptive waypoints provided the most structure for pilots and kept aircraft closest to their altitude and speed targets at each waypoint. Pilots also provided feedback that integrating descriptive waypoints into charts and displays could help them manage vertical speed and intercept targets more easily. Future research areas include integrating descriptive waypoints with advanced cockpit systems and using them for traffic and terrain avoidance.

1. Enhancing Pilot Ability to Perform CDA with
Descriptive Waypoints
1
Systems Engineering Research Laboratory
California State University Northridge (CSUN)
10/19/2011
Authors:
Michael LaMarr & Dr. Nhut Ho System Engineering Research Laboratory
Dr. Walter Johnson & Vernol Battiste, NASA AMES
Joe Biviano Lockheed Martin

2. • Previous Research
• Objective
• Method and Experimental Design
• Results
• Conclusion
2
Overview

3. Conventional Approach Vs. Continuous
Descent Approach (CDA)
3
10,000 Feet
4,000 feet
ILS Glide Slope
Runway
Continuous
Descent Approach
Conventional
Approach
Current Problem with Conventional Approach
• Cost of fuel = 27% operation cost to airlines
• People complain about loud aircraft noise near
airports
• Can’t expand runways
• Limited aircraft throughput at night
Implementation challenges for CDA:
•Air Traffic Controllers (ATC) unable to maintain separation between decelerating aircraft
•Pilots have difficulty maintaining a tight vertical flight profile
Proposed Solution Continuous Descent
Approach
• Idle engine at Higher altitude
• Less noise is produced
• Less fuel is consumed ~220lbs
• Fewer emissions produced
21 NM

4. Previous Research
• Structure
▫ Reynolds et. al. (2005)
 ATC have difficulty predicting future trajectories of decelerating aircraft
 Standardizing CDA deceleration profiles would allow ATC to use structured
based abstractions and maintain aircraft separation
▫ Ho et. al. (2006)
 Pilots had highest speed
accuracy with three gates
 Having too few or too many
targets could increase workload
4

5. • Vertical Navigation (VNAV) Uncertainty
▫ Clarke, Ho, et. al. (2004)
 The altitude constraint has priority over the speed constraint
 VNAV performance was dependent on pilot behavior: initiating CDA too late
and delays in flaps deployment negatively affected the desired performance
• 4D Guidance (x, y, z, and Time)
▫ Williams (2008)
 Provides an energy cue on a 2D vertical Nav display
 NAV display helps pilots manage throttle and speed brake usage during CDA
 Helps increase spacing and minimizes Required Time of Arrival deviation
5
Previous Research

6. • To determine the feasibility of using gates for CDA initiated near top
of descent, and number of gates and locations
• Formalize gates as Descriptive Waypoints (DW): A Descriptive
Waypoint is a target along the flight path that gives the pilot a target
altitude and Indicated Airspeed (IAS)
6
Objective

7. 7
23,000 feet
Starting Speed IAS 305
Airport
IAS 160
Alt 2000
5nm71.6nm
NM to Runway
IAS 305
Alt 23000
(SDF)
0nm
5nm to SDF
Runway
1 Descriptive Waypoint Pilot
Handout

8. 8
23,000 feet
Starting Speed IAS 305
Airport
IAS 160
Alt 2000
5nm38nm71.6nm
NM to Runway
IAS 305
Alt 13000
IAS 305
Alt 23000
Cheri
(SDF)
Alt<10
IAS 240
Alt 10000
0nm
5nm to SDF
21.1nm
Runway
3 Descriptive Waypoints Pilot
Handout

9. 9
23,000 feet
Starting Speed IAS 305
Airport
IAS 160
Alt 2000
10nm 5nm22.1nm38nm56nm71.6nm
NM to Runway
IAS 160
Alt 5000
IAS 305
Alt 13000
IAS 305
Alt 18000
IAS 305
Alt 23000
Cheri
(SDF)
Alt<10
18nm to cheri
1Onm to SDF
IAS 240
Alt 10000
0nm
5nm to SDF
Runway
5 Descriptive Waypoints Pilot
Handout

10. Method and Experimental Design
• A 3 x3 within-subject factorial design was used
▫ Number of Descriptive Waypoints: One, Three, and Five
▫ Tail Wind Speed Conditions: Slow, Normal, and High
• Dependent Variables
▫ Deviation from Descriptive Waypoint altitude and Indicated Airspeed
▫ Average power use of aircraft
▫ Workload (Part-task), Pilot acceptance, & Pilot Feedback
10

11. Participants
• Twelve IFR rated pilots with glass cockpit experience with 590 to
23,000 (Mean 7,660) hours flight time
• Eleven males, one female
• Age: 24 to 67, average = 38
• Pilots range from flying 757, CRJ, beachcraft, private jets and a lear
jet
• Two pilots had real world CDA experience, one in a simulator
11

12. Facilities
• Study was run in Systems Engineering Research Laboratory (SERL),
California State University Northridge
• Pilot was in a room with a one-way mirror
• Flight chart was on desk for pilot to use
12

13. Mode Control
Panel (MCP)
Primary Flight
Display
(PFD)
13
Navigation Display
Flaps
Landing Gear
Speed Brakes
MACS
Flight Simulator Display

14. 14
CSD
Vertical Situation Display

15. Results
15

16. 0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
1 DW 3 DW 5 DW
16
Power usage
Std 2.31 Std 2.39
AveragePowerPercentage
Std 3.45

17. 17
Average Altitude Deviation
AltitudeDeviationinFeet
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

18. 0
1
2
3
4
5
1 DW 3 DW 5 DW
18
Std .67
Std .75
Std .72
Workload
AverageWorkload

19. Pilot Feedback
• Pilots would feel comfortable (4.42 out of 6 on a scale) having the
DW put into a flight chart
• Pilots would prefer 10-30nm spacing for DW
• Pilots said they would fly more accurate if they had their standard
tools
• Changes recommended from the pilots
▫ DW flight chart should implement distance to each DW and angle of descent
▫ Implementation of DW into vertical NAV display
19

20. Pilot Feedback cont.
• DWs helped them manage their vertical speed by giving them
checkpoints
• DW 3 target at 10,000 feet altitude was seen as the most important
DW by the pilots
• Pilots said they used speed brakes as little as possible
• Responsibilities and tasks for Pilot Flying (PF) and Pilot Monitoring
(PM)
▫ PF should fly vertical speed and IAS, and determine whether the targets at DWs
are met
▫ PF should vocalize plan and callouts to PM
▫ PM should monitor targets, air speed, IAS, and DWs, do all calculations for PF,
setting altitudes, MCP, work the gear and flaps, crosschecking altitude inputs, and
talking to ATC
20

21. • The five DW condition gave structure for the pilots, and the aircraft
consistently flew similar flight paths and were closer to their DW
target altitudes
• The five DW condition used slightly more power (one percent) than
the one and three DW conditions.
▫ With automated assistance such as altitude prediction, pilots believed that they
would intercept DW without resorting to level flight
• The results of increasing performance in the three and five DW
conditions support the use and implementation of DW into CDA
procedures
21
Summary and Conclusion

22. • Full sim with all tools available to pilots
• Have a co pilot or a researcher act as one
• Include a Jeppesen chart with the DW chart
• Update DW flight chart based off pilot feedback
• Integrate DW into CSD or vertical NAV display
• Use DW with CSD and 3D guidance
for traffic avoidance
• Use DW with CSD and 3D guidance
for terrain avoidance
22
Future Research

23. References
• Lowther, M. B., Clarke, J-P., & Ren, L., (2007). En Route Speed Change Optimization for Spacing Continuous
Descent Arrivals
• Reynolds, H., Reynolds, T. & R. Hansman, J. (2005). Human Factors Implications of Continuous Descent
Approach Procedures for Noise Abatement in Air Traffic Control. 6th USA/Europe Air Traffic Management R&D
Seminar, Baltimore, USA, June 27-30.
• Ho, N. T., Clarke, J-P., Riedel, R., & Omen, C. (2006). Development and Evaluation of a Pilot Cueing System for
Near-Term Implementation of Aircraft Noise Abatement Approach Procedures. Journal of American Institute of
Aeronautics and Astronautics.
• Clarke, J-P., B., Ho, N. T., Ren, L., Brown, J. A., Elmer, K. R., Tong, K-O & Wat, J. K. (2004). Continuous Descent
Approach: Design and Flight Test for Louisville International Airport. Journal of Aircraft, 41(5), 1054-1066.
• Reynolds, H. (2006). Modeling the Air Traffic Controller’s Cognitive Projection Process. MIT International
Center for Air Transportation Department of Aeronautics & Astronautics Massachusetts Institute of Technology
Cambridge, MA, 2006
• Stell, L. (2010). Predictability of Top of Descent Location for operational Idle-thrust Descents. American Institute
of Aeronautics and Astronautics.
• Kupfer, M., Callantine, T., Martin, L., Mercer, J. & Palmer, E., 2011, Controller Support Tools for Schedule-Based
Terminal-Area Operations, Ninth USA/Europe Air Traffic Management Research and Development Seminar
(ATM2011)
• Alam, S, Nguyen, M.H., Abbass, H.A., Lokan, C., Ellejmi, M., & Kirby, S., 2010, A Dynamic Continuous Descent
Approach Methodology for Low Noise and Emission, 29th IEEE/AIAA Digital Avionics Systems Conference,
October 3-7, 2010
• Ren, L. & Clark, J-P., 2007, Flight Demonstration of the Separation Analysis Methodology for Continuous Descent
Arrival, Draft paper for 7th USA/Europe ATM 2007 R&D Seminar, Barcelona, Spain, 2-5 July 2007.
23

24. References
• Clark, J-P., Bennett, D., Elmer, K., Firth, J., Hilb, R., Ho, N., Johnson, S., Lau, S., Ren, L., Senechal, D., Sizov, N.,
Slattery, R., Tong, K., Walton, J., Willgruber, A., Williams, D. (2006). Development, Design, and Flight Test
Evaluation of a Continuous Descent Approach Procedure for Nighttime Operation at Louisville International
Airport
• Koeslag, M. F., (1999) Advanced Continuous Descent Approaches –An algorithm design for the Flight
Management System-.
• Moore, S. (2009). Benefits of Highly Predictable Flight Trajectories in Performing Routine Optimized Profile
Descents: Current and Recommended Research. Environmental Working Group Operations Standing Committee
2009 Annual Workshop, NASA Ames.
• Williams, D. (2008). Flight Deck Merging and Spacing and Advanced FMS Operations. EWG Operations
Standing Committee Meeting.
• Coppenbarger, R., Mead, R., Sweet, D., (2009). Field Evaluation of the Tailored Arrivals Concept for Datalink-
Enabled Continuous Descent Approach. Journal of Aircraft, 46(4), July–August 2009
• Global Aviation Navigation, Inc., (2009). Retrieved May 2009, from http://www.globalair.com/d-
TPP_pdf/00239IL17R.PDF
• Thomas, L. & Wickens, C. (2006). Individual Effects of Battlefield Display Frames of Reference on Navigation
Tasks, Spatial Judgments, and Change Detection. Ergonomics, 49, 154-1173.
• Cowen, M., John, M., Oonk, H., & Smallman, H. (2001). The Use of 2D and 3D Displays for Shape-Understanding
versus Relative-Position Tasks. Human Factors, 43(1), 79-98.
• Symmes, D., & Pella, J. (2005). Three-Dimensional Image. Microsoft® Encarta® 2006 [CD]. Redmond, WA:
Microsoft Corporation, 2005.
• Prevot, T., (1998). A Display for Managing the Vertical Flight Path - an Appropriate Task with Inappropriate
Feedback-. International Conference on Human-Computer Interaction in Aeronautics Montreal, Canada, 1998
24

25. 25
References
• Johnson, W., Ho, N., Martin, P., Vu, K-P., Ligda, S., Battiste, V., Lachter, J., Dao, A. (2010), “Management Of
Continuous Descent Approaches During Interval Management Operations,” 29th Digital Avionics Systems
Conference, Salt Lake City, Utah.
• Prevot, T., Callatine, T., Kopardekar, P., Smith, N., Palmer, E., Battiste, V., (2004). Trajectory-Oriented
Operations with Limited Delegation: An Evolutionary Path to NAS Modernization. AIAA 4th Aviation Technology,
Integration and Operations (ATIO) Forum, Chicago, IL, September 2004.