FAA AAR-410 December 5, 20061 FAA Airport Pavement Roughness R&D u Gordon Hayhoe, AAR-410, FAA William J. Hughes Technical Center, Atlantic City, New Jersey,

December 5, 2006 1 FAA AAR-410

FAA Airport Pavement FAA Airport Pavement Roughness R&DRoughness R&D

Gordon Hayhoe, AAR-410, FAA William J. Hughes Technical Center, Atlantic City, New Jersey, U.S.A. www.airporttech.tc.faa.gov Continue development and maintenance of

ProFAA (in process). Develop a standard for CA Profilograph

simulation (in process). Compare measured and simulated aircraft

response (data analysis in process). Conduct a pilot subjective rating study using the

FAA 737 full-motion simulator (planning).


ProFAA Computer ProgramProFAA Computer Program Intended to provide analysis of airport pavement

roughness by computing indexes and simulating aircraft response.

An inertial profiling system was developed for measuring runway and taxiway longitudinal elevation profiles from threshold to threshold. Constant profile measurement speed not necessary. Profiles are not absolute – somewhere between absolute

and normal high-pass filtered. Suitable for high-speed aircraft simulation.


Profile MeasurementProfile Measurement

FAA Methodology

Standard High-Pass Filter Methodology

Measurement speed – profile measured from zero speed to zero speed


ProFAA Computer ProgramProFAA Computer ProgramBasic Index DisplayBasic Index Display


Airport Pavement Profile Data Airport Pavement Profile Data Measured AtMeasured At

Sixteen Airports U.S.A. and Foreign 4 Large Hub, 3 Medium Hub, 5 Feeder

4 Foreign large international Flexible and Rigid Pavements Runways and Taxiways


Straightedge versus ProfilographStraightedge versus Profilograph

Straightedge-Profilograph,Runway,PCC(98*4)

y = 223.38x - 13.086

R2 = 0.8844

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0

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200

0 0.2 0.4 0.6 0.8

Straightedge (in)

Pra

filo

gra

ph

(in

/mile

)

Straightedge-Profilograph,Runway,PCC(98*4)

y = -103.79x2 + 278.44x - 18.153

R2 = 0.8948

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Straightedge (in)

Pro

filo

gra

ph

(in

/mile

)

Straightedge-Profilograph,Runway,AC(254*4)

y = 1169.1x2 + 73.411x - 3.054

R2 = 0.7241

01020304050607080

0 0.05 0.1 0.15 0.2 0.25

Straightedge (in)

Pra

filo

gra

ph

(in

/mile

)

Straightedge-Profilograph,Runway,AC(254*4)

y = 321.82x - 15.326

R2 = 0.7073

-100

1020304050607080

0 0.05 0.1 0.15 0.2 0.25

Straightedge (in)

Pra

filo

gra

ph

(in

/mile

)


Straightedge versus Boeing Straightedge versus Boeing BumpBump

Straightedge-Boeing,Runway,PCC(98*4)

y = 0.902x0.841

R2 = 0.4264

00.20.40.60.8

11.21.41.6

0 0.2 0.4 0.6 0.8

Straightedge (in)

Bo

ein

g

Straightedge-Boeing,Runway,AC(254*4)

0

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1

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Straightedge (in)

Bo

ein

g


FAA TC Boeing 727-100QC FAA TC Boeing 727-100QC Instrumented Aircraft, N40Instrumented Aircraft, N40

The FAA WJHTC operated a fully instrumented Boeing 727-100 until it was damaged about five years ago during an arrestor bed test.

Measurements were made with N40 in 1997 on a runway and taxiway at a medium size regional airport.

At the same time longitudinal profile measurements were made with the FAA profiler.

The data from these test is now being analyzed to compare measured airplane responses with simulated responses.


Why Wait Until Now to Analyze the Why Wait Until Now to Analyze the Data.Data.

Development of pavement thickness design procedures and associated full-scale traffic testing consumed most available R&D resources.

The AAR-410 budget has recently been increased and a significant portion of the increase is assigned to roughness work over at least the next three years.


N40 on Jacks in the HangarN40 on Jacks in the Hangar


Installation of Axle Strain GagesInstallation of Axle Strain Gages






Main Gear Force CalibrationMain Gear Force Calibration


Interior and Instrumentation RacksInterior and Instrumentation Racks


Speed Sensor on Nose GearSpeed Sensor on Nose Gear


N40 on Jacks in the HangarN40 on Jacks in the Hangar


Variables Measured on N40.Variables Measured on N40.

Vertical and side forces and torque at each wheel on main and nose gears.

Speed at nose gear. Three-axis accelerations at aircraft cg and

floor of cockpit. Inertial guidance system outputs. Displacement of control surfaces, throttle,

etc.


Tests Run November 3 and 4, 1997Tests Run November 3 and 4, 1997

Run No. Time (pm)

Speed, Knots

Number Blocks

Runway File Name Fuel Wt., lbs

1 1:30 40 36 31 HRT040 45,000 2 1:37 40 72 13 HRT04013 3 1:47 40 90 31 HRT0403 4 1:53 100 60 13 HRT100 42,000 5 2:10 100 60 31 HRT10033 40,800 6 3:25 60 70 13 HRT06013 40,600 7 3:32 60 80 31 HRT06031 38,800 8 3:38 TO/Land 80 13 HRTTOLND 38,600 9 4:45 ~10 10 Taxiway HRTTAX 10 9:43 TO/Land 80 31 HRTTOL31 37,000 11 9:56 80 80 13 HRT08013 35,800 12 10:10 80 80 31 HRT08031 34,500 13 10:17 ~20 130 Taxi from 13 HRTTAX13 34,000 14 10:23 ~20 240 Taxi from 31 HRTTAX31 33,500


Tests Run December 12, 1997Tests Run December 12, 1997

Run No. Time

Speed, Knots

Number Blocks

Runway File Name Fuel Wt., lbs

1 11:16 40 90 13 HST04013 45,000 2 11:21 40 90 31 HST04031 43,000 3 11:32 100 80 13 HST10013 42,200 4 12:21 100 60 31 HST10031 41,000 5 12:29 60 80 13 HST06013 40,000 6 12:46 60 80 31 HST06031 39,000 7 12:49 TO/Land 80 13 TOLAND13 38,500 8 1:17 TO/Land 80 31 TOLAND31 36,000 9 1:20 80 80 13 HST08013 35,500 9 1:34 80 80 31 HST08031 34,500






N-40 Versus Simulation

0

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Distance (ft)

Ma

in V

ert

ica

l F

orc

es

, L

bs

Sim-Total Main Vertical N40-Total main vertical,Lbs

Sim-Avg=152057

N40-Avg=142606



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2000

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Distance (ft)

No

se

Ve

rtic

al

Fo

rce

s,

Lb

s

Sim-Total Nose Vertical N40-Total Nose vertical,Lbs

Sim-Avg=7995

N40-Avg=6825



-0.5

-0.4

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0

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Distance (ft)

CG

Ac

ce

l, g

Sim-CG Accel N40-CG Accel(norm),G

Avg(Accel-CG) close to 0



-0.8

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Distance (ft)

CP

Ac

ce

l, g

Sim-CP Accel N40-C/P Accel-Z,G

Avg(Accel-CP) close to 0


These are Preliminary StepsThese are Preliminary Steps Continuing work will include variation of

simulation parameters such as: Flexible body modes. Pitch moment of inertia for cockpit

comparisons. Strut model parameters – primarily Coulomb

and hydraulic friction. Modify simulation program to accept

varying speed.


Includes damping forces due to: Velocity squared hydraulic damping. Strut seal Coulomb friction. Strut bearing Coulomb friction due to strut inclination. Two-to-one breakaway-to-sliding friction.

All wheels lumped into one equivalent wheel. Unsprung mass is ignored. Gas compression spring. Linear tire spring with linear damping.

ProFAA Computer ProgramProFAA Computer ProgramStrut ModelStrut Model


Subjective Pilot Rating Study Using Subjective Pilot Rating Study Using Full-Motion Simulator - ObjectivesFull-Motion Simulator - Objectives

Develop a rating scale for pilot subjective response to vertical cockpit vibrations excited by longitudinal pavement surface elevation disturbances.

The scale to range from very smooth to exceedingly rough.

Identify on the rating scale limits for cockpit vibration resulting in uncomfortable conditions and unacceptable conditions.

A similar project has been proposed to ACRP but using field data.


Why Use a Simulator and Not Why Use a Simulator and Not Operational AirplanesOperational Airplanes

For Test repeatability. Rapid change in profile characteristics. Cost. Safety.

Against Concerns about simulator fidelity. Difficult to change cockpit characteristics.


FAA Full-Motion 727 Simulator, Now FAA Full-Motion 727 Simulator, Now replaced with a 737 Simulator.replaced with a 737 Simulator.Located at Oklahoma CityLocated at Oklahoma City


Previous ExperiencePrevious Experience AAR-410 has run projects on the FAA 727

simulator for about 15 years. High-speed exit geometry and lighting configurations. High-speed ground handling. Airplane landing into and arrestor bed. General lighting and visual guidance studies.

The person responsible for simulator operation has a Ph.D. in human factors as well as being a National Resource Specialist in Simulators.

E1927 “Conducting Subjective Ride Quality Pavement Ratings.


Subjective Pilot Ratings - ScheduleSubjective Pilot Ratings - Schedule FY06 (funding obligated)

Develop scope and test plan. Establish procedures for setting roughness profiles in the

simulator computer program. Develop preliminary rating scale and questionnaire.

FY07 Continue test plan, etc. Preliminary simulator study with a small number of pilots to

test the scales and other procedures. Finalize procedures.

FY08 Run the full experiment with the necessary number of subjects

and profiles. Analysis and report

Documents

FAA AAR-410 December 5, 20061 FAA Airport Pavement Roughness R&D u Gordon Hayhoe, AAR-410, FAA William J. Hughes Technical Center, Atlantic City, New Jersey,