In late 2008, the Transportation Security Administration made a stunning and little-noticed projection: If a private jet flew into an urban office building, 3,000 people could be killed. That's a higher death total than in the Sept. 11 attacks.
The TSA used the estimate to justify a plan to impose security rules on 15,000 private jets, including requirements that jet operators check passengers against watch lists and keep weapons off their planes.
The proposal was labeled as potentially crippling to jet owners. More than 7,000 protest letters from private pilots, businesses and aviation groups forced the TSA to rewrite its plan. A new proposal is likely late this year, and security rules could take effect in 2011 — a decade after the 9/11 attacks.
The TSA's struggle to regulate private jets reflects the deep dispute over how much danger is posed by the planes, which fly in and out of thousands of airports with no TSA oversight. Even the Homeland Security Department is divided.
The TSA said large private planes "could be used effectively to commit a terrorist act." The Homeland Security inspector general said in a 2009 report that private aviation "does not present a serious homeland security vulnerability" requiring new TSA rules.
"There is a balance because we don't want to really restrict (private) aviation," said Vahid Motevalli, former head of George Washington University's aviation safety and security program. "But it shouldn't be totally ignored."
The jets the TSA is looking at are a small portion of the nation's 220,000 private airplanes. Most private planes are small, piston-engine aircraft individuals fly out of community airports primarily for recreation and instruction. The government considers those planes too light and too slow to cause major damage, although it does restrict those planes from flying above high-profile events such as the Olympics, the Super Bowl and national political conventions.
Small planes are receiving new scrutiny after Joseph Stack deliberately flew his four-seat, piston-engine plane into a Texas office building last week, killing himself and a worker in the building, which suffered extensive damage.
The TSA plans to review the damage to determine whether it should consider new security measures.
Senate Commerce Committee Chairman Jay Rockefeller, D-W.Va., said the crash shows private planes must be regulated. "It was horrific," said Rockefeller, Congress' leading advocate for imposing security rules on private flights. "It just shows what one person can do."
The overall reaction from Congress has been relative silence. Few lawmakers have made public statements or called for hearings into the Texas crash. Several experts said in interviews that the death toll shows the limited harm a small plane can cause.
"To me, it's just a risk you're going to have to accept," aviation-security consultant Rich Roth said. "There's nothing we could really do short of saying you guys can't fly planes."
Douglas Laird, another security expert, agreed. "You can do about as much damage with that plane as you could with an SUV loaded with fuel," he said. "I can't get agitated about it."
Roth said the dramatic TV footage of flames and heavy smoke billowing out of the seven-story office building in Austin could inspire copycats: "Unfortunately, I think every terrorist out there is looking at this and thinking, That looks kind of neat."
The Austin crash has mobilized private-aviation groups, which have been influential in countering TSA efforts to impose security rules on private jets.
The 400,000-member Aircraft Owners and Pilots Association (AOPA) said on its website that as soon as reports of the plane crash were broadcast, it got in touch with TSA officials to "provide detailed information" about private aviation "and maintain reason."
"AOPA is working to ensure there are no new regulations as a result of the incident," the organization said.
Ed Bolen, CEO of the National Business Aviation Association, said private-aviation groups have launched their own security initiatives aimed at spotting suspicious activity at small airports and suspicious purchases of private airplanes.
The crash last week doesn't suggest new rules are needed, Bolen said. "I think this has a lot to do with a troubled individual," he said. "I don't think it's a reflection of the industry."