Originally, $900,000 was budgeted for inspections, but Feger got permission in April from the airport authority to use an extra $500,000 for inspections, pushing up the cost to $1.4 million.
Airport spokesman Victor Gill said the additional money will come from a $5.9-million contingency fund set aside for unexpected costs and changes.
Commissioner Terry Tornek said that seeing the inspection costs jump from $1.4 million to $2.15 million so quickly was troubling.
"Part of the reason this is of great concern [is] … it erodes confidence in budget forecasting going forward," he said.
Randy Duncan, program director for project management contractor gkkworks/STV, said inspection costs rose because the construction contractor decided to go with a hybrid design option that used less-expensive materials such as concrete, but required extensive redesign work.
Duncan said inspections, which are required by code, ensure that construction matches the design changes and meets safety standards.
Feger added, however, that the airport will ultimately save money by going with the hybrid option.
"The hybrid option was $82 million, and the steel option was $92 million," Feger said. "You can argue that you're spending another million dollars in testing, but you saved 10, so you net nine."
The project also includes construction of a parking structure to replace the parking capacity lost when parking Lot D was closed to make room for the transportation center.
The new parking structure is 87% complete and is expected to be done in July, Feger said.
Some of the additional costs could also be attributed to unforeseen complications, Duncan said, but others were due to the contractors trying to make up for lost time when design changes were required.
One significant change came from the Burbank Fire Department, which required fire- and fuel-safety systems on each floor of the transportation center because it will house rental-car facilities that will each have gas-pumping stations.
"It's due to the aggressive scheduling of both contractors that has resulted in … a less-efficient deployment of our [inspectors]," Duncan said.
Feger did report a piece of good news about the project — the contractors on both the parking structure and transportation center have reported no serious incidents and accidents.
If the project is completed with that sterling safety record, the airport could be in line for a rebate that could be as high as seven figures, Feger said.
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[For the records, June 12, 2013: An earlier version of this story incorrected stated the amount of money in the project's contingency fund.]