The National Business Aviation Association (NBAA) and Aircraft Owners and Pilots Association (AOPA) are warning a U.S. District Court of potential wide-ranging ramifications should the city of Santa Monica receive clearance to close Santa Monica Airport (SMO) next year.

In an amicus curiae brief, NBAA and AOPA tell the U.S. District Court for the Central District of California that if Santa Monica is successful, “the consequences could be to open up an opportunity for the owners of hundreds of other public use airports to consider the diminution or elimination of their operations – potentially leading to the substantial crippling of the nation’s air transportation infrastructure.”

The city Oct. 31 filed a lawsuit seeking control over the fate of SMO, arguing that it has “unencumbered title to the airport property and its availability ... to use the airport property as it chooses.” The city has discussed the possible closing of the airport after July 2015.

FAA has long held that the city must continue operating the airport under a 1948 agreement – an Instrument of Transfer. That post-World War II agreement would give the government the option for taking control of the airport property if the city ceases operating an airport there.

FAA has claimed that the court should dismiss the Santa Monica case because it is past a 12-year statute of limitations for challenges involving U.S. interests in property. The city, however, believes that since FAA ostensibly did not lay claim to the airport until 2008 under a separate lawsuit that it is well within the statute of limitations.

In the amicus brief, NBAA and AOPA side with FAA, saying “the facial conditions of the 1948 Instrument of Transfer are clear, and were repeatedly acknowledged by Santa Monica at later dates. Thus the city’s claim of ignorance at this late date about the effect of this plain language at issue amounts to a naked and parochial effect to undermine the national air transportation system.”

The associations point out consequences of closing the airport would have on the Los Angeles basin area, forcing the shift of operations to other regional airports that are already at or near capacity. With more than 100,000 annual operations, the airport is a “significant reliever,” NBAA and AOPA say. They also stress the economic importance of the airport with about 175 mostly small businesses based their employing close to 1,500 workers and accounting for about $275 million in total annual output.

Beyond the local ramifications, the associations note that possibility 200 other airports are subject to similar post-World War II transfer agreements. A number of those are major facilities. In the Los Angeles area, they include Van Nuys Airport and Los Angeles International. They also include some of the busiest airports in the nation, such as Chicago O’Hare, Boston Logan, San Francisco International, and Milwaukee General Mitchell, among others.

Some of the airports with transfer agreements are trying to make similar claims as Santa Monica, the associations say, citing as an example Marin County, Fla., home of Witham Field.

“The U.S. is not building airports at any significant pace, so any loss of access to any existing facility is a matter of serious concern to the associations, and can have an impact far beyond the airfield and community at issue through ripple effects,” they say.

“It is imperative that the FAA maintain jurisdiction over SMO,” NBAA and CEO Ed Bolen says, calling the fight over the future of SMO a “bellwether moment.”

AOPA General Counsel adds the airport “should not be closed because the city is no longer satisfied with the agreements it made with the federal government. “We think the FAA has presented a compelling argument for dismissing the lawsuit.”