eral Aviation Administration
William J. Hughes Technical Center
Atlantic City International Airport, NJ 08405



Human Visual and Tactile Ice
Detection Capabilities under
Aircraft Post Deicing Conditions




Edmundo A. Sierra, Jr., Titan Corporation
Kimberlea Bender, Titan Corporation
Isabelle Marcil, Transport Canada, Transportation Development
Centre
John DAvirro, APS Aviation Inc.
Edward Pugacz, FAA Office of Aviation Research, Flight Safety
Branch
Frank Eyre, Transport Canada, Transportation Development
Centre






February 2006








Technical Report

This document is available to the public through the National Technical
Information Service (NTIS), Springfield, Virginia 22161. A copy is
retained for reference by the William J. Hughes Technical Center IRC.



U.S. Department of Transportation
Federal Aviation Administration

NOTICE

This document is disseminated under the sponsorship of the U.S. Department
of Transportation in the interest of information exchange. The United States
Government assumes no liability for the contents or use thereof. The United
States Government does not endorse products or manufacturers. Trade or
manufacturer's names appear herein solely because they are considered
essential to the objective of this report. This document does not constitute
FAA certification policy. Consult your local FAA aircraft certification office
as to its use.

This report is available at the Federal Aviation Administration William J.
Hughes Technical Centers Full-Text Technical Reports page:
www.tc.faa.gov/its/act141/reportpage.html in Adobe Acrobat portable
document format (PDF).

ii 1. Report No.


DOT/FAA/TC-06/21
2. Government Accession No.

3. Recipient's Catalog No.

5. Report Date

4. Title and Subtitle
Human Visual and Tactile Ice Detection Capabilities under Aircraft Post Deicing
Conditions
February 2006

6. Performing Organization Code

ACB-330
7. Author(s)

Edmundo A. Sierra, Jr., Kimberlea Bender, Isabelle Marcil, John DAvirro, Edward
Pugacz, Frank Eyre
8. Performing Organization Report No.

DOT/FAA/TC-06/21

9. Performing Organization Name and Address

Federal Aviation Administration
10. Work Unit No. (TRAIS)

William J. Hughes Technical Center
Atlantic City International Airport, NJ 08405
11. Contract or Grant No.



12. Sponsoring Agency Name and Address
FAA Office of Aviation Research, Flight Safety Branch
13. Type of Report and Period Covered

Technical Note

14. Sponsoring Agency Code

Transport Canada, Transportation Development Centre

15. Supplementary Notes

.
16. Abstract

Human Visual and Tactile ice detection capabilities while inspecting deiced aircraft surfaces have not been quantified. This
report includes the findings of a human ice detection performance test conducted in April 2005 by the FAA Office of Aviation
Research, Flight Safety Branch (William J. Hughes Technical Center) and Transport Canada, Transportation Development
Centre. Six male deicers from AeroMag 2000 at Montreal Pierre Elliot Trudeau International Airport participated in the
experiment. We used PMG Technologys cold chamber in Blainville, Quebec, Canada to create an environment whose
temperature was -5° C with 92% humidity. Ice samples were created by APS Aviation on either white painted or unpainted
aluminum panels, as either a 315 cm
2
circular patch or fully covering the panel, with thicknesses ranging from .2 mm to 1.2 mm.
All of the test samples were covered with aircraft deicing fluid. We used a two-alternative forced-choice procedure in which each
participant observed two panels in sequence, and then indicated on which of the two panels ice was present. The data showed that
participants were 1) unable to visually detect ice less than .8 mm thick when it was in the shape of a patch and on a painted white
panel; 2) unable to visually detect ice 1.2 mm thick when it covered the entire panel; and 3) participants could easily detect ice of
any thickness using a tactile check.
17. Key Words
Deicing, ground icing, tactile inspections, visual inspections,
GIDS, Ground Ice Detection Systems, human factors,
engineering psychology, psychophysics, cold chamber, human
capabilities, human limitations, aviation



18. Distribution Statement
This document is available to the public through the National
Technical Information Service, Springfield, Virginia, 22161
19. Security Classif. (of this report)

20. Security Classif. (of this page)

21. No. of Pages

22. Price

Unclassified
Unclassified

113
Form DOT F 1700.7 (8-72)
Reproduction of completed page authorized

Technical Report Documentation Page


iii Acknowledgements
This report reflects the contribution of many individuals from various organizations, and the
authors would like to acknowledge them and thank them for their efforts. Without them, this
experiment would not have been a success.
We would like to thank Sherri Magyarits (FAA WJHTC, Simulation and Analysis Group) and
Nicole S. Racine (Titan Corporation, Air Traffic Systems Division) for their assistance during
the initial stages of the experiment.
Mario N. Rosa, Alex Leclair and Jean-François Morin from Aero Mag 2000 Montreal provided
deicing expertise for sample creation, shakedown activities, and served as participants.
Nicoara Moc, Nicolas Blais, and Sami Chebil were responsible for creation of the ice samples
and setting up the cold chamber.
We would also like to thank Christina Narlis for her dedication as a Test Administrator and for
her help in reviewing and translating data collection materials.

iv Table of Contents
Page
Acknowledgements.........................................................................................................................iv

Executive Summary......................................................................................................................viii

Acronyms........................................................................................................................................ix
1. Introduction................................................................................................................................ 1
2. Research Approach ..................................................................................................................... 2
2.1. Two-alternative Forced-choice Procedure........................................................................... 2
2.2. Statistical Decision Theory and the Psychophysical Experiment........................................ 2
2.2.1. The Decision ................................................................................................................. 2
2.2.2. Computation of Percent of Correct Responses ............................................................. 3
2.2.3. Use of Percent of Correct Responses............................................................................ 4
2.3. Summary .............................................................................................................................. 4
3. Methodology............................................................................................................................... 4
3.1. Participants........................................................................................................................... 4
3.1.1. Deicers .......................................................................................................................... 4
3.1.2. Research Personnel ....................................................................................................... 6
3.2. Equipment ............................................................................................................................ 6
3.2.1. Climatic Chamber ......................................................................................................... 6
3.2.2. Ice Samples ................................................................................................................... 7
3.3. Data Collection .................................................................................................................... 7
3.3.1. Session Design .............................................................................................................. 8
3.3.2. Trial Design .................................................................................................................. 9
3.3.3. Participants.................................................................................................................. 10
3.3.4. Practice, Motivation, and Stability.............................................................................. 10
4. Visual and Tactile Procedure Specifics ................................................................................ 11
4.1. Visual Observations ........................................................................................................... 12
4.1.1. Sample......................................................................................................................... 12
4.1.2. Visual Checking Method ............................................................................................ 13
4.2. Tactile Observation............................................................................................................ 14
4.2.1. Sa