Runway Roughness Evaluation- Boeing Bump All of these functions are tied to proper pavement maintenance and the availability of the pavement for safe aircraft operations · 2013-7-11

Copyright © 2012 Boeing. All rights reserved.

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The statements contained herein are based on good faith assumptions and provided for general information purposes only. These statements do not constitute an offer, promise, warranty or guarantee of performance. Actual results may vary depending on certain events or conditions. This document should not be used or relied upon for any purpose other than that intended by Boeing. BOEING is a trademark of Boeing Management Company.

Runway Roughness Evaluation- Boeing Bump Methodology

Michael Roginski, PE, Principal Engineer Boeing Airport Technology Group

ALACPA Seminar of Airport Pavements

September 10-14, 2012, Panama City

Copyright © 2006 Boeing. All rights reserved. | 2

Outline

Types of Roughness and Boeing Bump Criteria

Profiling Equipment Comparison

Case Studies

Standardization of Roughness Criteria

Conclusions


What Types of Roughness are We Concerned About at Boeing? Three Types of Structural Concerns Affecting Aircraft:

1) Limit Loads – Single Discrete Bumps which could lead to structural failure. Currently addressed by Boeing Bump Criteria

2) Fatigue Loads – Continuous Large Wavelength Bumps exceeding once per flight fatigue criteria based on change in vertical acceleration

3) Landing Gear Truck Pivot Joint – Continuous Short Wavelength Bumps. Only a real concern in Russia and CIS countries

Each type imposes a different runway roughness criteria. Types 2 and 3 require dynamic analysis.

Current standards address mainly first two types. Third type is relatively unknown, and not directly addressed in

current standards.


Pavement Maintenance Priorities

Runway pavements should fill the following functions

1.) Provide adequate bearing strength- addresses structure of pavement

2.) Provide good ride quality- addresses surface geometrics

3.) Provide good surface friction characteristics- addresses texture and slope of pavement

All of these functions are tied to proper pavement maintenance and the availability of the pavement for safe aircraft operations


Boeing Runway Roughness Criteria-Single Event Limit Load

Bump length, m

Bum

p he

ight

, cm

Acceptable

0 10 20 30 40 50 0

5

10

15

20

Excessive

60

RUNWAY ROUGHNESS CRITERIA L

H

L

H

L

H

Unacceptable- Closure of runway

Repairs needed Pilot complaints


Long Wave Depression Bump Definition

Runway Station, m

Elevation, m

6+304 6+220 6+250 6+280

4.82

4.90

5.00

5.10 Centerline

North

South

3C

3N

3S

Rod Length (10m-120m rods tested ) Bump Length

Bump height


Details of the Boeing Method- Long Wave Depression

Runway station, m

Ele

vatio

n, c

m

60 220 0

10

20

30 North

South

40

100 140 180 260

8 cm

10 cm

13 cm

10 cm

10 cm bump worse due to shorter bump length- all rod

lengths must be checked

8 cm bump worse than 10 cm bump- all points along profile for a given rod

length must be checked


Boeing Bump Analysis- Plot of Worst Bumps


Boeing Bump Analysis- Detail of Excessive Bumps

Region with Highest Roughness

-3

-2

-1

0

1

2

3

4

0 10 20 30 40 50 60 70 80 90 100

Runway Position (m)

Pro

file

Hei

ght (

cm)

Significant Bump


Boeing Bump Analysis- Detail of Excessive Bumps

Region with Highest Roughness

-6

-5

-4

-3

-2

-1

0

1

2

2400 2410 2420 2430 2440 2450 2460 2470 2480 2490 2500

Runway Position (m)

Pro

file

Hei

gh

t (c

m)

Significant depression


Fatigue Life – Exceedance of Airplane Load Factors

Incremental vertical acceleration at CG (g units)

Exc

eeda

nces

per

flig

ht

.10 0.2 0.4 0.6 0.8 1.0

10

100

1.0

Landing Rollout (Smooth runway)

Takeoff Roll (Smooth runway)

Takeoff Roll- (Rough runway)

Aircraft fatigue life affected


Landing Gear Truck Beam Failure- Short wave Roughness Issue


Short Wavelength Runway Profile Analysis Power Spectral Density (Overall Runway)

• Shows frequency of occurrence of short wave bumps- 2 to 7 meter range

Acceptable threshold RMS = 1.45

Smooth runway- Below threshold

Rough runway- Above threshold


Runway Profile Analysis 3D Relative Power Spectral Density

Run

way

Dis

tanc

e (m

)

Rel

ativ

e R

unw

ay P

SD (d

B)

Bump Wavelength (m) Rough Acceptable

Runways in CIS countries identified having short wave roughness exceeding the PSD threshold must be serviced periodically(i.e. inspect

and lube) by airline


Airports Surveyed by Boeing for Roughness


Comparison Between Boeing Criteria and other Criteria

Bump length, m

Bum

p he

ight

, cm

Acceptable

0 10 20 30 40 50 0

5

10

15

20

Excessive

60

Unacceptable

USAF airplane design criteria MIL-A-008862A paved airfields

Runway vertical curve (ICAO annex 14) ICAO tolerable

limits (3cm over 45m)

FAA straightedge criteria (6mm over 5m)

ICAO straightedge criteria (3mm over 3m)


Runway Profiling Equipment Comparison

Manual rolling inclinometer profiler

High Speed Inertial Laser profiler

Manual rod and level device


Pavement Assessment Process

Compare profiles from 3 profiling devices

Verify that the regions of roughness along the profile were similar in magnitude for all profilers

Compare 2 Lines of Survey (CL and 15 Feet Left of CL)

Roughness determined using Boeing Bump Criteria was compared for all 3 devices

Initial consultant request to review runway 07/25 came to Boeing in 2007. Main concern was fatigue, primarily region 1 dual bump exceeding the once per flight fatigue limit.


07 25

Painted Threshold on 07 end

950’ -2500

Roughest Areas

7450- 8750’

Areas of Roughness from APR survey- 2006

Region 2

Region 1

Copyright © 2006 Boeing. All rights reserved. | 20 Image: Courtesy Google Maps

Region 1

Region 2

Areas of Roughness from APR survey- 2006


0.0

2.5

5.0

-2.5

0.0

2.5

5.0

0.0

2.5

5.0

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Denver Runway 7-25(Grade Removed)

Elevatio

n (in)

Elevatio

n (in)

Elevatio

n (in)

Distance (feet)

7-25 15FT LOC 7-25 CL 7-25 15FT ROC

APR Profiles-Regions 1 and 2 as noted


Bump Index Definition

0

5

10

15

20

25

0 10 20 30 40 50 60

Bump Index=Actual Bump Height/Height from curve

Acceptable-Bump Index < 0

Unacceptable-Bump Index > 0

Bump Length (m)

Bum

p H

eigh

t (cm

)


Runway 07/25 Centerline Profile- Bump Index Comparison

0

0.2

0.4

0.6

0.8

1

1.2

0 500 1000 1500 2000 2500 3000 3500 4000

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 500 1000 1500 2000 2500 3000 3500 4000

0

0.2

0.4

0.6

0.8

1

1.2

0.0 500.0 1000.0 1500.0 2000.0 2500.0 3000.0 3500.0 4000.0

APR

Boeing

FAA

Index 1.0

Index 1.0

Index 1.0


Conclusions

Profiles from all three devices seem to match well- areas of roughness on runway correlate between all three.

Boeing bump analysis consistent – bump index values, although differing in magnitude, are maximum at the same locations along the runway

Locations of overall worst bumps in same areas for all three profiling devices

All three profilers are useful in determining general areas of roughness needing repair


Boeing Runway Analysis-Case History 1 Unacceptable Condition


Boeing Runway Roughness Assessment-Unacceptable Condition-Plot of worst bumps

0

1

2

3

4

5

6

7

8

0 20 40 60 80 100 120 140 160 180 200

Bump Length (ft)

Bum

p he

ight

(in)

Unacceptable

Excessive2004 profile

2005 profile

Acceptable


Boeing Runway Roughness Assessment-Unacceptable Condition 2004 vs. 2005 Survey

0

1

2

0 500 1000 1500 2000

2004

2005

Primary takeoff direction Region of pilot complaints

Excessive

Unacceptable

0

1

2

0 500 1000 1500 2000

Excessive

Unacceptable


Boeing Roughness Criteria Applied to Temporary Construction Ramps

Bump length, m

Bump height, in

Acceptable limit

25 0 5 10 15 20 0

2

4

6

8

10

0 10 20 30 40 50 60 70 80

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1/100 slope

1/200 slope

Bump length, (ft)

Bump height, cm


Runway Ramping Recommendations

A. Ramping prior to aircraft traffic Predominant direction of traffic

Old surface Ramp

Overlay thickness x Milled area

Overlay thickness x

B. Surface preparation prior to resumption of paving Cut area to depth y

Old surface y

1. When overlay thickness x < = 5 cm, then ramp slope = 1.0% 2. When overlay thickness x > 5 cm, then ramp slope = 0.5% 3. Depth y should be at least 2 times the maximum aggregate size

Notes

Overlay thickness x

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Working Toward an Industry Standard


Pavement Roughness- Current Situation

There is no industry standard which clearly defines when a airfield pavement has become “too rough”

Problems can be aircraft specific

New construction smoothness criteria is no longer applicable as pavement deteriorates

Action by the airport is typically initiated by pilot complaints- FAA currently doing aircraft simulator research to assess pilot feedback on runways of varying roughness.


US Guidance on Roughness

FAA Advisory Circular 150/5380-9(released 9/30/09)

FAA Software PROFAA

Includes Boeing Bump


FAA Guidance on Roughness

NEW CONSTRUCTION

AC 150/5300-13, Airport Design Surface Gradient

Maximum grade allowance

Change in grade provisions

AC 150/5370-10F, Standards for Specifying Construction of Airports

Construction tolerances must be met

Acceptance criteria for smoothness- straightedge or profilograph

Experience has shown that the current FAA grade and straightedge criteria provide pavements that are safe for aircraft operations.


ICAO Roughness Curve Approved for Annex 14, Amendment 10, 4th Edition

Bump length, m

Bum

p he

ight

, cm

Acceptable

0 10 20 30 40 50 0

5

10

15

20

Excessive

60

Unacceptable

Temporarily acceptable


ICAO Guidance- Annex 14, Attachment A Surface Unevenness

| 35

Surface Irregularity Minimum acceptable length of irregularity (m)

3 6 9 12 15 20 30 45 60 Maximum surface irregularity height (cm) 2.9 3.8 4.5 5 5.4 5.9 6.5 8.5 10

Temporary acceptable surface irregularity height (cm) 3.9 5.5 6.8 7.8 8.6 9.6 11 13.6 16

Unacceptable surface irregularity height (cm) 5.8 7.6 9.1 10 10.8 11.9 13.9 17 20

If the maximum limits are exceeded, corrective action should be undertaken as soon as reasonably practicable to improve the ride quality. If the temporarily acceptable limits are exceeded, the portions of the runway that exhibit such roughness should have corrective measures taken immediately if aircraft operations are to be continued. If the unacceptable limits are exceeded and the roughness resides in the area of aircraft operations, then the runway should be closed until repairs are made to restore the condition to the acceptable region.

The maximum permissible step type bump, such as that which could exist between adjacent slabs, is simply the bump height corresponding to zero bump length at the upper end of the acceptable region of the roughness curve. The bump height at this location is 1.75 cm.


Conclusions

Runways may become intolerably rough due to The onset of pavement structural failure (age) Adverse environmental conditions Improper repairs or non-standard temporary construction ramps

Airport operators are not usually aware of the impact of roughness on aircraft- pilot complaints typically initiate action

The Boeing criteria will enable airports to: Determine the extent of roughness Locate the source of roughness Make rational decisions for the best course of action

Standardizing the roughness criteria for both US and international airports through FAA advisory circulars and ICAO documentation provides proper guidance for developing an airport’s pavement management system


Thank you!

| 37

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Documents

Runway Roughness Evaluation- Boeing Bump All of these functions are tied to proper pavement maintenance and the availability of the pavement for safe aircraft operations · 2013-7-11