Even though they were airborne, military jets were unable to get into position where they could have shot down a suspicious plane over Washington last month, and miscommunication among key figures in America's air defenses transformed a routine flight by Kentucky's governor into a dramatic evacuation of the Capitol (search), officials say.

Bush administration officials are to testify before Congress on Thursday about the problems encountered June 9, when a flight by Gov. Ernie Fletcher (search) caused a breathless evacuation of the Capitol building on the day Ronald Reagan's (search) body was brought to lie in state.

Officials said the real-life drama proved what security experts have been saying since Sept. 11, 2001 — prevention of an aerial attack depends on measures taken well before a plane enters the restricted air space in Washington.

The Federal Aviation Administration (search), NORAD (search) and other security agencies have made significant changes since the episode to address shortcomings exposed that day, officials said.

"The purpose of the hearing is find out what went wrong, and have they fixed it," said House Transportation Committee Chairman John Mica, R-Fla.

"The good news is we evacuated the Capitol in record time. The bad news was it was a false alarm and it appears there was a lack of coordination between FAA and Homeland Security, and we can't afford that kind of a gap in the future," he said.

NORAD confirmed 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. This failure led to the evacuation of the Capitol Building and surrounding office buildings when, in fact, there was no threat."

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 officials said the government has additional layered defense in Washington, such as ground missiles, that could be deployed if jets aren't in a position to intercept.

The entire scrambling of the jets, however, 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 (NCRCC), which coordinates air security in the nation's capital.

Officials divulged 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 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 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.

Officials said several lessons have been learned from the episode and several new precautions have been taken. One FAA contract employee involved in the episode has been removed from a post.

The NCRCC and FAA now can view the same radar system, and both FAA controllers and civilian pilots have been re-warned that planes without fully functioning transponders will not be allowed into Washington airspace at any time.

The June 9 episode followed secret drills last December in which Homeland Security planes posing as terrorists were able to penetrate Washington airspace in several tests.