Aggravated by recent reports about the the inability of airport security screeners to detect weapons and bombs, Senators on Tuesday once again left little doubt that they see major problems in the Transportation Security Administration.

"What we're doing clearly isn't working," said Sen. Ron Johnson (R-WI) at a Senate hearing, noting a variety of troubles at the TSA.

"These matters are troubling and must be addressed," Johnson said.

Echoing his concern was the Inspector General of the Department of Homeland Security, whose job it is to oversee the work of the TSA, as he minced no words about the agency's work on airport security.

"Unfortunately, although nearly 14 years have passed since TSA’s inception, we remain deeply concerned about its ability to execute its important mission," Inspector General John Roth told a Senate hearing.

"Despite spending billions on aviation security technology, our testing of certain systems has revealed no resulting improvement," Roth said.

Whistleblowers at the hearing also described an agency rife with bureaucratic infighting, one that does not appreciate red flags being raised from within.

"A culture of fear and distrust has been created in the agency, also impacting morale and performance of employees," said Rebecca Roering, who works for the TSA at the Minneapolis-St. Paul airport.

TSA nominee to appear at Wednesday hearing

As Senators and investigators rattled off a laundry list of troubles at the TSA, it was all a warm up for Wednesday, when the President's nominee to head the agency appears for a second confirmation hearing.

"The biggest thing that he needs to understand is an acknowledgement that there is a significant challenge here," Inspector General Roth said of nominee Peter Neffenger, the number two official at the Coast Guard.