At what is only its second public hearing since it got up and running at the beginning of the year, the commission also will hear calls for a complete overhaul of the way Congress oversees the country's intelligence agencies.
Among the witnesses scheduled to appear Thursday is a Transportation Security Administration official who last year revealed that -- prior to the Sept. 11 attacks -- specialists warned repeatedly about poor security at the nation's airports, but were ignored by their managers.
Bogdan Dzakovic's complaint was the subject of an inspector general's inquiry last year.
According to the government's special counsel, Elaine Kaplan, the inquiry "substantiated the crux of Mr. Dzakovic's allegation: that the Red Team Program was grossly mismanaged and that the result was the creation of a substantial and specific danger to public safety."
The elite Red Team -- for which Dzakovic worked -- consisted of undercover agents who conducted "covert penetration testing" at the nation's airports for the Federal Aviation Administration. The FAA was then responsible for overseeing passenger and luggage screening and other security measures.
Red Team members would try to identify gaps in security by attempting to smuggle fake guns and bombs onto planes, and they succeeded with alarming frequency.
Dzakovic now works for the Transportation Security Administration, the federal agency set up by Congress in the wake of the Sept. 11 attacks to dramatically improve aviation security, especially passenger and luggage screening.
Dzakovic says that his prepared testimony focuses on the weakness of the system prior to Sept. 11, "I don't want to reveal exactly what I'm going to say," he told United Press International Wednesday, "but it's strong stuff. I'm taking the gloves off."
But he added that -- despite the establishment of the TSA and the employment of over 55,000 federal employees as screeners -- he believes things are not much better today.
"There are serious indications that aviation security has not significantly improved since Sept. 11," he said.
Although TSA officials insist they have made enormous strides, Dzakovic's doubts are shared by lawmakers and relatives of those who died on Sept. 11.
Earlier this month, UPI reported exclusively that Congress' investigative arm, the General Accounting Office, was launching an inquiry into how the TSA trains, equips and supervises its screeners, how they measure their performance, and how the new system compares to its pre-Sept. 11, 2001, counterpart.
One congressional staffer, who asked not to be named, said at the time the call for an investigation stemmed -- at least in part -- from skepticism about the TSA's own inspection procedures.
"They're only being tested by their own people at the moment," he told UPI, "we're a little suspicious of that."
He also disputed the TSA's assessment of how well their new systems are performing.
"Their own testing shows that they still have a ways to go on both training and equipment issues," he said, declining to give details, which he said were classified.
Others are blunter.
"The aviation security system in this country was hopelessly incompetent on Sept. 11 and it continues to be seriously flawed even now," Stephen Push, a spokesman for several families' groups, told UPI.
"I hope that the commission when they question these witnesses tomorrow will get to the problem of this problem ... I want to see strong recommendations on how it can be improved," he added.
The commission, on which sit former members of both House and Senate intelligence committees, will also hear calls for a reform of the way that lawmakers supervise the work of the country's intelligence agencies.
"One of the very explicit and direct mandates to the commission was to look very comprehensively at the whole issue of congressional oversight -- how Congress could reform its oversight of intelligence agencies and all its work as it relates to the fight against terrorism," commission member Tim Roemer, a former Democratic House member from Indiana, told UPI.
One of the witnesses will be the current chairman of the House Intelligence Committee on which Roemer served, Rep. Porter J. Goss, R-Fla.
Goss also co-chaired the joint House-Senate inquiry into Sept. 11 last year.
"One of the things he (Goss) will be talking about is the recommendations that the joint inquiry made last year," said his spokeswoman, Julie Almacy.
Among those recommendations, which included the appointment of a Cabinet-level intelligence czar, and the overhaul of the FBI's counter-terrorism work, an appeal to the Sept. 11 commission to work out how Congress' intelligence oversight work could be done better.
Roemer says the commission will need to look at many issues.
"Should the intelligence committees be separate (in the Senate and the House), or should there be one joint committee? Should the members continue to be appointed for rotating terms, or should (they) be allowed to build up expertise like all the other committees? ... Should there be a permanent oversight and investigative subcommittee ... or should they continue to be distracted by budget and terrorism briefings?"
"These are very critical questions," he concluded.
Roemer says the other issue he will want to hear about from Goss and other House and Senate intelligence committee members giving evidence is what gaps there are in the work of the joint inquiry.
"What did the joint inquiry not do very well that the independent commission needs to follow through on?"
He says one of these as-yet insufficiently explored areas is the role of the president's closest advisers in the National Security Council.
He says that the NSC is the "nexus" where vital policy decisions about the fight against terrorism were ultimately made.
"This is a very key issue for us and we need to get a better look at it."
Roemer says the joint inquiry was not able to satisfactorily look at these issues, despite having interviewed Clinton national security adviser, Sandy Berger: "We were not able to get much cooperation or any live interviews with people from the Bush administration NSC. It was a significant missing link in the joint inquiry's investigation and it's a 'must do' for the 9-11 commission."
He said officials told the joint inquiry that they were too busy prosecuting the war against terror to give evidence, but added that only by a thorough examination of the circumstances of Sept. 11 could the government avoid repeating the mistakes of the past.
One of the issues that proved controversial for the joint inquiry was their access to presidential daily briefings, or PDB's -- the document that summarizes intelligence about threats to the country. It is central to any effort to work out what warnings the president and other senior administration officials might have had before the attacks.
"I would hope that that is all on the table, that we'll be able to get the PDBs, to get minutes of meetings," said Roemer, "I would hope they will put that all on the table."
He said that the commission needed to move "aggressively" to ensure its right to see important documents was not blocked by claims of executive privilege.
"I'm sure we'll have negotiations with the White House about a host of documents ... We need to start those conversations now ... If they claim executive privilege, we have other arrows in our quiver that we might contemplate using."
The 10-member commission -- five Democrats and five Republicans -- was set up last year. It is mandated to report by spring 2004.