In the 23 years Rep. James P. Moran has been in Congress, he’s seen his Northern Virginia district morph into a megalopolis of broad boulevards, bustling developments and skyscrapers. Now he’s fearful that a federal agency wants to put a cap on this burgeoning skyline to help airlines and airports make more money.

Most of Rosslyn’s big buildings would be too tall under the proposal, he says. So, too, would be communication towers proposed for the Pentagon and the George Washington Masonic National Memorial, not to mention buildings in New York, Phoenix, Chicago, Boston and Miami.

The Federal Aviation Administration sees development around the nation’s airports — including tall buildings, microwave towers and wind turbines — as encroaching on the airspace that jetliners need to land safely. In particular, the FAA worries that an aircraft crippled by an engine failure might not have time to navigate through an obstacle course.

This has led to an FAA proposed rule change to limit structure heights, commonly known as the “one engine inoperative rule.” That’s why the Northern Virginia Democrat, who is retiring at the end of this term, spoke out at a recent House committee hearing.

“Most people have no clue what that means,” Moran said of “one engine inoperative.”

Moran said the rule change would require that new structures be 90 feet shorter than previously allowed. Nearly 4,000 existing structures near airports nationwide would exceed the cap, he said, though they would be exempt from the rule. Nearly 170 of those too-tall structures are in Northern Virginia, he said, which is home to both Reagan National and Dulles International airports.

The FAA can't respond. The agency is bound to keep silent during the federal rulemaking process until the window for comments from the general public closes June 27. The proposal, published last month in the federal register, doesn’t contain the specific heights that Moran referred to at Wednesday’s hearing.

The FAA notes, in the register, that it isn’t authorized to grant or deny building permits, but points out that if it considers a project a safety risk, “zoning authorities and private insurers may be reluctant to permit construction.”

FAA officials are known to feel that creating one pathway in and out of each airport for planes crippled by sudden loss of an engine would suffice, and they don’t feel the need for limits on all structures surrounding airports.

But Moran, still wary, cited a 16-page analysis of the rule’s potential impact.

“It’s going to cost local communities millions of dollars, and ultimately billions of dollars, in economic growth,” Moran said. “There are thousands and thousands of buildings under consideration that would by impacted by this.”

Why would the FAA do this, he asked rhetorically?

“I asked the airlines, and they said it just doesn’t happen that one of the engines goes out. We’ve done millions of flights. It hasn’t happened,” he said. “What’s behind this is that the airlines want to be able to load more passengers and more cargo so they can make more money. And, of course, the airport authorities are happy with that because they get some of that money.”

The analysis cited by Moran was done by the Weitzman Group, a New York-based consulting firm for the real estate industry.

Prepared by the group’s president, Marilyn Weitzman, and her staff, the analysis concludes that the FAA proposal would reduce the acceptable height of new properties from 250 feet to 160 feet, a difference of about nine floors.

Although existing structures and those under construction would not be affected by the new rule, the Weitzman report outlines immediate and long-term potential consequences, most of which pertain to developers and real estate values.

One potential threat is that insurance premiums and mortgages would go up for homeowners associations and upper-floor condo owners on the theory that if disaster struck, top floors might not be rebuilt because of the FAA rule. Weitzman also said limiting floors would reduce residential density and encourage suburban sprawl.

Placing limits on building height would reduce the value of the land and could make construction financing more difficult to find, the analysis says. And when too-tall buildings were torn down, their replacements would have to be shorter.

“A skyline of a city, and therefore part of that city’s visual identity, may be defined in part by structures deemed to be obstructions,” the analysis says, and if those buildings require modification or reconstruction, “the skyline of a city might change.”

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