Airport Pavement Roughness Research

Airport Pavement Roughness Research

Introduction

The objective of this research project is to develop practical procedures for measuring and characterizing the longitudinal roughness of airport runway and taxiway pavements. An essential part of this effort is the definition of a profile index that characterizes the level of roughness encountered by aircraft using the airport pavements. Key tasks that have already been completed include: development of profiling equipment, field measurements of runway profiles at airports, data reduction and profile identification, computer simulations and development of index computational procedures.

Airport pavements are closely monitored and evaluated to determine performance over the life span of the pavement. Engineers are required to design, construct, and maintain airport pavements to meet accepted standards. Those required standards – outlined in FAA Advisory Circulars (AC) 150/5300-13 - “Airport Design” and AC 150/5370-10 – “Standards for Specifying Construction of Airports” - include pavements being structurally sound, providing sufficient drainage, and providing high braking performance for airplanes. Roughness is another parameter that is observed and analyzed by airport personnel; however, several factors unique to airports make it difficult to utilize roughness as a parameter for maintaining airport pavement quality.

As defined in the dictionary, roughness is “the characterization of a surface marked by irregularities, protuberances, or ridges.” The practical application of this definition for airport pavements is measuring and defining those surface irregularities. The Federal Aviation Administration provides guidelines for measuring and evaluating roughness within the FAA AC 150/5380-9 – “Guidelines and Procedures for Measuring Airport Pavement Roughness”. The AC divides pavement roughness into two categories: single event bumps and profile roughness. Single event bumps are surface irregularities that occur over a shorter distance of the pavement and could represent safety concerns for aircraft suspension systems. Profile roughness includes surface irregularities over long distances of the pavement and could represent frequency responses in aircraft that may lead to suspension fatigue, impaired cockpit operations, reduced breaking capabilities, and passenger discomfort.

Of paramount concern when evaluating airport roughness is the safety of aircraft passengers. While highway vehicles have suspension systems designed to withstand the common occurrences of surface roughness, aircraft suspension systems are designed to handle the impact of landings. As such, they may not be properly equipped to reduce stress and fatigue from common occurrences of surface roughness. Therefore, it is necessary to control the effects from airport roughness at the pavement surface rather than through the aircraft suspension systems.

Single Event Bumps

Currently, FAA AC 150/5380-9 only addresses procedures for identifying and evaluating the effects of single bump events. Airport personnel are required to collect longitudinal profiles of airport runways at the center line and necessary center line offsets. This advisory circular recommends profiles of the center line, and 10 feet lateral offset for Airplane Design Groups II and III, and 17.5 feet lateral offset for Airplane Design Groups IV, V and VI. These offsets represent likely airplane main gear locations relative to the runway center line. Methodology for profile data collection is not specified. Instead, the advisory circular requires a minimum survey interval of 0.82 feet for evaluation method called Boeing Bump.

The Boeing Bump is the FAA accepted methodology for evaluating airport runway longitudinal profiles for single event bumps. This methodology measures vertical deviations at the pavement surface from a series of generated virtual straight edges. Software developed by the FAA – ProFAA – is capable of calculating the maximum Boeing Bump value at each survey point along a longitudinal profile. The software then reports these values and specifies when any location exceeds acceptable limits for in service airport runways.

Getting the ProFAA and ProGroove Program Package

The ProFAA and ProGroove programs can be downloaded from the current branch website

ProFAA

"ProFAA" is the Federal Aviation Administration's computer program for computing pavement elevation profile roughness indexes. The data analysis performed by the program includes the calculation of the following indexes: Straight Edge, Boeing Bump, International Roughness Indexes(IRI), California Profilograph (PI), and RMS Bandpass.  ProFAA should be used in conjunction with the FAA Standard, Advisory Circular AC 150/5380-9.

Sample Profiles

Three samples profiles are provided for use with ProFAA. The pavements are: very smooth, intermediate, and very rough.

ProGroove

"ProGroove" is the Federal Aviation Administration's computer program for groove evaluation of longitudinal profiles. ProGroove should be used in conjunction with the FAA Standard, Advisory Circular AC 150/5320-12C.AC 150/5320-12C “Measurement, Construction, and Maintenance of Skid-Resistant Airport Pavement Surfaces”


Sample Profiles

Two samples profiles for use with ProGroove.

These standards are distributed by the FAA Office of Airport Safety and Standards, AAS-1, at the FAA Headquarters Washington, DC.  Advisory Circulars are available at AAS-1's Airport (150-series) Advisory Circulars web site.

Presentations

Full-Scale High Tire Pressure Tests on Heated Pavement HTP FS Report - Submitted to ICAO Aerodrome Operations and Services Working Group

2006 ASCE T&DI Airfield and Highway Pavement Specialty Conference

2006 ASCE T&DI Airfield and Highway Pavement Specialty Conference Atlanta, GA

Conference Info

Airport Pavement Roughness Index Relationships Using the Federal Aviation Administration (FAA) Profiling System

Song, Hayhoe_ASCE 2006

Airport Pavement Roughness Index Relationships Using the Federal Aviation Administration (FAA) Profiling System

Song, Hayhoe_ASCE 2006


2007 FAA Tech Transfer Conference

Current California Profilograph Simulations and Comparisons

Song, Teubert_2007 FAA Conf

Current Califa Profiornilograph Simulations and Comparisons

Song, Teubert_2007 FAA Conf


2012 4th International Conference on Accelerated Pavement Testing

4th International Conference on Accelerated Pavement Testing 19 – 21 September 2012 University of California Pavement Research Center Davis, California, USA

Conference Info

Rut Depth Measurement Method and Analysis at the FAA’s National Airport Pavement Test Facility (NAPTF)

Song, Hayhoe, Aponte_APT 2012

Rut Depth Measurement Method and Analysis at the FAA’s National Airport Pavement Test Facility (NAPTF)

Song, Hayhoe, Aponte_APT 2012


2012 Transportation System Workshop - PROFAA Workshop

ProFAA Workshop Transportation Systems Workshop 2012 5 – 8 March 2012 Renaissance Austin Hotel, Austin, Texas

Conference Info

Rut Depth Measurement Method at the FAA’s National Airport Pavement Test Facility (NAPTF)

Song, Hayhoe_NAPTF RD

Pavement Profile Analysis Methods Using ProFAA

Song, Hayhoe_ProFAA

Case Study of Domestic Airport Runway Profile Data Analysis Using ProFAA 

Song_ProFAA Workshop


2014 FAA Tech Transfer Conference

Profile Data Comparisons for Airfield Runway Pavements

Song, Larkin, Augustyn_2014 FAA Conf

Profile Data Comparisons for Airfield Runway Pavements

Song, Larkin, Augustyn_2014 FAA Conf

Airport Pavement Roughness Simulator Project

Larkin, Song, Stapleton, Hudspeth_2014 FAA Conf

 

 

Profiles

Name

Data Files

BDZ

​​BDZ
EJB EJB
MBG MBG
NZS NZS
PTV PTV
QPT QPT
UBC UBC
Various CSV Files / Index Computations CSV / Roughness Index Table
    

 

Airport Pavement Simulator Roughness Project

Airport surface roughness is controlled very closely during construction and contractors are held to high standards.  These standards include maximum variances along the longitudinal and transverse axes of new runway and taxiway construction.  However, once the construction is complete, the FAA does not have a reliable method for determining when airport pavement becomes “too rough” due to deterioration.  In support of the goal to develop a method for evaluating in-service pavement roughness, this study developed a rating scale for pilots’ subjective response to vertical cockpit vibrations experienced by longitudinal pavement surface elevation disturbances.

Cherokee CRC (CCRC) began work on the Airport Pavement Roughness study with the FAA in September 2008 using the FAA’s Boeing 737-800 full flight simulator in Oklahoma City.  The Boeing 737-800 simulator’s roughness model was modified to allow the use of real world airport surface roughness profiles and to increase the fidelity of the ground model response to roughness.  A methodology was developed for presenting surface roughness profiles and obtaining pilot roughness evaluations.  Test scenarios, roughness rating forms, and pre-brief and post-brief sessions were developed and refined during a series of pilot studies in 2010 and 2011.  National Cooperative Highway Research Program (NCHRP) highway rideability studies [Ref. 1] were reviewed and used as models for developing the airport pavement rideability studies.

A preliminary roughness study was conducted November 8 – 10, 2011 using the FAA’s Boeing 737-800 full flight simulator located at the Mike Monroney Aeronautical Center in Oklahoma City.  The study consisted of four pavement rideability rating sessions with three pilots per session, for a total of 12 subject pilots. Subject pilots were presented with a series of eighty taxiway and runway pavement roughness test scenarios. Subjective pilot ratings and objective measures of cockpit accelerations were collected for all sessions.  A data analysis was performed to correlate the pilot ratings with cockpit accelerations.  [Ref. 7].

The Boeing 737-800 CAE full flight simulator is an FAA certified Level D flight training device, providing a six-degree of freedom motion system, high resolution visual display, and sound systems.

The Boeing 737-800 simulator flight model runs at an iteration rate of 60 Hertz (Hz) and provides a simulation of the aircraft equations of motion and interaction with the ground and air.  The flight model assumes a rigid aircraft and implements buffets due to airframe flexing only in specific instances where needed for realism.  The flight model sends aircraft linear and rotational velocities and accelerations to the simulator visual and motion systems.

The motion system provides motion cues for aircraft maneuvers.  Because the motion system actuators provide limited travel, sustained low frequency accelerations are not possible and the motion software is optimized using a complex set of filters to provide cueing for the most critical aircraft training maneuvers such as takeoffs, aborted takeoffs, and landings.

 

Roughness Preliminary Study

Pilot Rating Forms

Video Edited

Reports from Simulator Research

In a continuation of the Federal Aviation Administration's (FAA's) research to determine acceptable limits for airport pavement roughness, the FAA Roughness Final Study was conducted on June 4 - 6 and June 11 - 13, 2013 using the FAA's Boeing 737-800 flight simulator at the Mike Monroney Aeronautical Center (MMAC) in Oklahoma City. Thirty-six pilots participated in the study over twelve test sessions. Subjective pilot ratings of pavement roughness and objective measures of cockpit accelerations were collected for all sessions. A data analysis was performed to correlate the pilot ratings with cockpit accelerations.

 

Boeing 737-800 (Draft Report)

Airbus 330-200 (Draft Report)

Study Data

Boeing 737-800

Airbus 330-200

Airport Roughness Study May-June 2013

Roughness Additional Analysis

 

The NAPTF gratefully recognizes the cooperation, assistance and simulator access provided by the Mike Monroney Aeronautical Center (MMAC), AFS-440 Flight Operations Simulation Branch, Oklahoma City, OK and Cherokee, CRC, S. Hudspeth, D. Stapleton, & J. Sparkman.

Additional Documentation

AC 150/5370-10G – “Standards for Specifying Construction of Airports”

“The standards contained in this AC relate to materials and methods used for the construction of airports. Items covered in this AC include general provisions, earthwork, flexible base courses, rigid base courses, flexible surface courses, rigid pavement, fencing, drainage, turfing, and lighting installation.”

·AC 150/5300-13 –“Airport Design”

“Contains the Federal Aviation Administration’s (FAA) standards and recommendations for the geometric layout and engineering design of runways, taxiways, aprons, and other facilities at civil airports”

· AC 150/5380 – 9 –“Guidelines and Procedures for Measuring Airport Pavement Roughness”

“Provides guidelines and procedures for measuring and evaluating runway roughness as identified by surface profile data of rigid and flexible airport pavements.  Provides technical procedures to quantify surface irregularities and to determine how surface irregularities may affect specific categories of airplanes.”

AC 150/5320-12 “Measurement, Construction, and Maintenance of Skid-Resistant Airport Pavement Surfaces”

“Contains guidelines and procedures for the design and construction of skid-resistant pavement; pavement evaluation, without or with friction equipment; and maintenance of high skid-resistant pavements.”

Runway Roughness Measurement Quantification and Application - The Boeing Method