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Project Experience: Portland International Airport, Oregon

The Challenge

The Port of Portland, operator of Oregon’s Portland International Airport (PDX), needed to determine the feasibility and location of a Ground Run-up Enclosure (GRE) to reduce the noise of aircraft engine run-ups in communities surrounding the airport. The Port was required by Oregon’s Department of Environmental Quality to meet the State’s strict noise regulations or face a permanent suspension of aircraft engine run-ups at PDX.

The Port identified three general areas on the airfield that could accommodate a GRE. Two of the sites were eliminated due to cost and navigational interference issues. The third site proved to be the best from an operational and site prep perspective, but it was also the closet of the three to the neighboring community.

The Strategy


  • Undertook extensive noise modeling to determine the optimum size and height of a GRE that would accommodate the diverse range of aircraft conducting run-ups at PDX
  • Assisted the Port in analyzing historical PDX wind data to determine the expected usability of the GRE
  • Prepared the technical specifications for the required insertion loss performance of the GRE as well as the acceptance test procedures to demonstrate that the GRE was performing as required

The Solution

After construction, HMMH conducted the acceptance test noise measurements. The GRE passed and has been in continuous use since May 2001 -- achieving a usability of 99 percent with no limit on nighttime run-ups. The PDX GRE has proven to be a success for the Port, the airlines, and the surrounding communities.