A training instructor with the Transportation Security Administration at Philadelphia International Airport pleaded guilty in federal court today to taking a bribe from a security officer.

Shannon Gilliam, 29, of Sharon Hill, potentially faces four to 27 months in prison under advisory sentencing guidelines.

Gilliam, who began working for the TSA in 2003 as a baggage screener and was promoted to training instructor in 2008, has been suspended with pay pending the outcome of the investigation, a TSA official said.

Prosecutors said Gilliam was responsible for training transportation security officers and to administer annual mandatory screening tests to officers who handle passenger and baggage screening at the airport.

The government's plea memo said that between August and October 2011 Gilliam took a $200 bribe from a TSO identified in the plea memo as "R.R." in exchange for ensuring a passing grade on the certification exam.

R.R. failed the exam twice, the plea memo said, then Gilliam took R.R. outside the testing room and explained he would take the test for R.R. in exchange for $200.

At the time, Gilliam was in financial trouble, owing back taxes and his house was up for sheriff's sale, the plea memo said.

Robert Datner, Gilliam's attorney, was not immediately available for comment.

Gilliam took the test for R.R. on Aug. 22 and received an initial payment of $100, the plea memo said.

A day earlier, R.R. was getting cold feet, and texted Gilliam not to take the test, but Gilliam never received the message, the plea memo said, and took the test as planned.

On Aug. 22, after Gilliam had already taken the test, R.R. texted: "It's been weighing on my mind and feel like it's not in my character. I appreciate u and ur help, but I need to do this on my own."

R.R. confessed to a supervisor that he had Gilliam take the test for him, the plea memo said, and federal agents set up a meeting between Gilliam and R.R. (who wore a wire) where the second $100 installment was paid, the plea memo said.

Contact Michael Hinkelman at 215-854-2656 or hinkelm@phillynews.com, or follow on Twitter @MHinkelman.