A top official at the Federal Aviation Administration (search) testified Thursday that protections are now in place to prevent the kind of harrowing incident that forced the evacuation of the Capitol last month after a plane carrying Kentucky Gov. Ernie Fletcher (search) entered unrestricted airspace.

Asked by lawmakers whether there could be a repeat of the scare, FAA vice president Linda Schuessler said, "We don't believe it can happen again."

She told a House hearing that steps taken since the June 9 incident include ensuring officials monitoring incoming flights to Washington have access to the same radar system and therefore the same information.

The National Capital Region Coordination Center (search), which coordinates air security in the nation's capital, previously used a different radar system from the FAA and that led to the confusion.

Fletcher's plane did not have a functioning transponder, which identifies the aircraft, yet it had received permission from the FAA to proceed to Washington. Schuessler said planes with malfunctioning transponders could not enter the restricted zone, 30 miles around Washington, in the future.

There also will no longer be exceptions granted to other rules that are required of planes entering the restricted zone, according to the FAA.

Still, some lawmakers say the lack of coordination and communication that led to the Capitol's evacuation worries them.

Military aircraft patrolling over Washington scrambled but were unable to get into position where they could have shot down the suspicious plane carrying Fletcher, officials said.

However Rep. Jim Moran, D-Va., said he worries a mistake will happen again that will lead to an unidentified plane getting shot down. "I think we're only very lucky that there hasn't been a catastrophic mistake made," he said.

The incident proved what security experts have been saying since Sept. 11, 2001, officials said, that preventing an aerial attack depends on measures taken well before a plane enters the restricted air space over Washington.

NORAD — North American Aerospace Defense Command — said that it scrambled two jets during the incident, but declined to be more specific because of the classified nature of its engagement rules. The fact that "the plane landed without incident June 9 indicates that the procedures developed since Sept. 11 work," it said.

Homeland Security spokeswoman Katy Mynster said, "We believe appropriate security measures were put in place based on the information we had at the time. ... Of course, we continue to look for ways to improve communications."

Members of Congress whose staffs have looked into the episode said the incident exposed flaws two years after the Sept. 11 attacks led to a major upgrade of America's security net.

"The incident raises the question: Does the existing no-fly zone around our nation's capital give sufficient time to intercept a terrorist-controlled flight?" said Rep. Jim Turner, D-Texas, the top Democrat on the House Homeland Security Committee. "Further it appears that the FAA miscommunicated with other agencies responsible for the protection of Washington."

Government, military and congressional officials said two F-15 fighter planes were already patrolling on June 9 in anticipation of the Reagan funeral and were diverted when security monitors saw the governor's plane as an unidentified and potentially hostile aircraft.

However, under the Pentagon's rules of engagement, the jets could not get close enough to be in position to shoot the plane down if it was indeed heading toward the Capitol, according to officials outside NORAD.

The officials declined to further describe the rules of engagement, except to say they are different for fighter jets in wide open areas than in urban areas and that they require several conditions to be met before a shootdown is considered possible.

The entire scrambling of the jets was unnecessary, caused by miscommunications between the FAA, which directs air traffic, NORAD, which protect America's air space from impending threats, and the National Capital Region Coordination Center, which coordinates air security in the nation's capital.

Officials said that:

—The FAA originally misdiagnosed the Kentucky plane as having a transponder that was functioning properly except for a failure to transmit its altitude. In fact, the plane did not have a functioning transponder, and such planes are supposed to be barred from Washington airspace.

—When the FAA recognized the plane did not have a transponder, it disregarded its rules and allowed the plane to proceed, putting the identification into its radar system manually.

—Because the Washington coordination center used a different radar system than the FAA, it was unaware of the special exemption and believed the plane was an unidentified and potentially hostile aircraft, causing NORAD to scramble its jets.