The proposed NFL stadium in Inglewood faces a new challenge, after the Federal Aviation Administration released a preliminary report saying the venue at the former Hollywood Park site is "presumed to be a hazard to air navigation."
The 27-page report issued Monday warned the proposed $1.86-billion stadium in Inglewood could interfere with radar that tracks inbound aircraft to Los Angeles International Airport.
"The configuration of the stadium between the two runways coupled with the uncertainty of its reflective properties is the root cause of the objection to this proposal," the report said.
The report offered various possible solutions that included relocating the stadium, reducing the height by more than 100 feet, reshaping the exterior or covering some surfaces with material that absorbs radar or isn't reflective.
The findings allow the developers, including St. Louis Rams owner Stan Kroenke, to resolve the issues although it could add time and expense to a plan that architects have been working on for more than a year. The proposal has been entitled, designed and, planners, say, the preparation work to begin construction on the 290-acre site is nearly completed.
"I had no doubt at all that we will all work out a reasonable set of mitigation measures and we will all be happy," said Chris Meany, senior vice president of the Hollywood Park Land Co., which controls the property.
"There is nothing about this that isn't in the ordinary course of business. This is the process you go through."
An FAA spokesman emphasized the report isn't a final determination, but an initial step to open negotiations with the project backers. They can take steps to mitigate the concerns or submit evidence in an effort to show the stadium wouldn't affect the airport radar.
The news comes at a critical time in the efforts to end the NFL's two-decade absence from Los Angeles. The league's Committee on L.A. Opportunities meets Wednesday in New York. The group will hear updates on the Inglewood project, as well as the rival proposal to build a stadium in Carson by the San Diego Chargers and Oakland Raiders. The three cities trying to keep their teams — San Diego, St. Louis and Oakland — also will make presentations.
The highest point of the proposed covered Inglewood stadium would be 290 feet above sea level, including a playing field that would be built 100 feet below ground in an effort to comply with FAA rules. The height is eight feet shorter than a planned stadium on the same site that received a "no hazard" determination from the FAA in 1995.
The FAA's examination of the current project, which started in June as a routine obstruction evaluation, found the stadium's height could create false images of aircraft or garbled images on radarscopes used by air traffic controllers.
"This is a critical area requiring precision monitoring of all aircraft activity," the report said.
Large portions of the stadium would be covered in a metal skin, something the report called "problematic" because of the potential for the material to reflect radar signals. The complexity of the stadium's exterior design, including "continually varying curves," complicated the FAA's effort to characterize the structure's response to radar.
Reducing the current height of the wave-shaped venue would be an exceedingly unlikely prospect at this late stage.
The report also suggested the extreme step of moving the stadium, the centerpiece for a sprawling mixed-use development that would include restaurants, retail space and a performance center.
"Were the stadium relocated away from the runway approach paths, chances for successful passage would greatly improve," the report said.
A more realistic option is the installation of radar-absorbing material at key locations around the stadium. The report estimated that would cost $40 to $80 per square foot.
The FAA evaluation focused on how the project's height, location and size would affect nearby air traffic. Such reviews are required by the FAA for a variety of construction projects.
"This occurs rather routinely with large construction projects such as the stadium in Inglewood," said Bill Withycombe, who retired in 2013 as the FAA's top official for a region that includes Arizona, California and Hawaii.
The Inglewood developers have 60 days from the receipt of Monday's report to respond to the FAA. Any changes to the stadium's design to address the report's concerns must be submitted for further review.
The matter won't be circulated for public comment because it's only an initial finding, the FAA spokesman said.
It's unclear what, if any, effect the report will have on the timetable for the privately financed stadium's construction. Developers have pledged to break ground in December. But NFL owners don't plan to vote on a franchise relocating until January at the earliest.
"We think everything is on track with where we are supposed to be," Meany said.
The project has previously faced scrutiny over its proximity to LAX. Two reports commissioned by the Anschutz Entertainment Group that became public this year questioned the proposed stadium's safety. One of the reports, by former Homeland Security Secretary Tom Ridge, said the stadium could be vulnerable to a terrorist attack. The former head of the National Transportation Safety Board, Mark Rosenker, suggested in another report that airplane parts could fall onto the venue.
Aviation experts questioned the findings and Inglewood Mayor James T. Butts Jr. denounced Ridge's report as "fraudulent."
In March, AEG abandoned its longstanding plan to build an NFL stadium in downtown L.A. in the wake of the stadium plans in Carson and Inglewood.
Times staff writer Sam Farmer contributed to this report.