New security screening procedures will be tested at O'Hare International in Chicago this summer to allow pilots to speed through checkpoints without undergoing scans or pat-downs, officials said.

It's a first step toward a more logical risk-based screening and away from the current system of treating pilots and passengers as equal potential security threats, according to the Transportation Security Administration (TSA).

O'Hare and Miami International will be the first test sites for the program called KnownCrew, with other hub airports, including Minneapolis-St. Paul, to follow later, according to airline pilot unions and airlines.

Expedited screening of flight attendants, who undergo less rigorous security and background checks than pilots do during the hiring process, will occur later, officials said.

But some experts are warning that KnownCrew contains security weaknesses that could be exploited by terrorists.

Verification of pilot identifications in the 90-day test at O'Hare will be made using photos and real-time airline employment data, whereas earlier tests also relied on biometric matches, such as fingerprints. Iris scans also provide a 100 percent match of the person on the scene with a record of the preapproved individual in a database.

"If somebody has forged a driver's license and a phony airline ID card of a current employee, that is a major loophole," said Robert Poole, director of transportation studies at the Reason Foundation, a public policy think tank.

"I don't understand why the TSA is allowing KnownCrew to go forward," Poole said. "It is very flawed from a security standpoint."

The Air Line Pilots Association International, the nation's largest pilots' union, and the Air Transport Association, which represents major airlines, are sponsoring the tests.

"We would define a photograph in the category of a biometric," said Steve Lott, spokesman for the Air Transport Association, which is collecting the pilot data from airlines and making it available to the TSA. "It's certainly not to the degree of an iris scan or a fingerprint, but we would say a photo can serve as a clear identifier of a person in combination with the information in the database."

The exclusion of concrete biometric validation concerns some lawmakers. U.S. Rep. Bennie Thompson, D-Miss., ranking member of the House Committee on Homeland Security, said he supports expediting pilots and flight attendants through security checkpoints. But, he said, "I believe it is imperative that this program include a biometric component to verify crew identities, thus implementing a higher standard of security and access control."

Airline officials acknowledge that the cost of implementing the pilot screening program is a consideration. Not all airlines possess fingerprint or iris scan data of their employees.

The organization representing U.S. airports is confident that biometrics will eventually be introduced.

"We are supportive of KnownCrew. The program is being designed in such a way that it is scalable to include biometrics over the long term, including for passengers," said Christopher Bidwell of the Airports Council International.