Butkovitz said he decided to go public with his objections after the March 13 runway accident in which a US Airways Airbus A320 had to abort takeoff, and initial reports said it was due to a blown tire.
The dispute began in October 2011, when the controller's office, which signs off on expenditures for city contracts, did a "close-out" walk-through on the taxiway and found rutting, or depressions, in the pavement caused by aircraft wheels.
The controller's engineer said the rutting should not have occurred just two years after the $9.5 million job was completed.
Based on the controller's concerns, an independent firm, Applied Pavement Technology of Urbana, Ill., was hired by the company that managed the construction for the airport to identify the cause of the rutting and propose both a short-term fix and long-term repair.
After reviewing available design and construction records and analyzing nine pavement samplings, Applied Pavement Technology noted a discrepancy between quality-assurance results provided by the construction-management company and its own testing of the pavement samples, which found "some dangerously low air voids that would make the mix susceptible to rutting."
Without additional sample testing and other information that "wasn't available or provided," Applied Pavement Technology could not be 100 percent definitive, said engineer David Peshkin, the report's author.
"Based on the samples that we looked at, the results were counter to what we would expect," Peshkin said in an interview. "On a newly resurfaced pavement that's properly designed and constructed, you would expect to get seven, if not 10, years without rutting or having to do anything to it."
In 2006, an airport design consultant issued guidance for milling and removal of underlying materials on the taxiway.
"It seemed like those recommendations were not followed to the letter," Peshkin said.
"We could never find any record of what thinking went into the decision not to follow the design report," he said. "It could have been a field decision, where the contractor came up and said, 'Do we have to do this?' And an inspector in the field said, 'Nah, we don't need to do that.' We could not say where it occurred."
But, the city Division of Aviation's own quality-assurance testing found the paving acceptable.
"The FAA criteria require that we test and check our paved surfaces, the runways and taxiways, at least once a day," said airport spokeswoman Victoria Lupica. "We, in fact, do it three times a day. All of our taxiways and runways, including Taxiway S, are safe for aircraft activity and, in fact, that taxiway is used every day by hundreds of aircraft."
"I can't speak to this particular situation because it is in litigation," Lupica added. "All our paved surfaces, and I can't stress this enough, are safe for use by aircraft."
In November, City Solicitor Shelley Smith directed Butkovitz to pay the $65,000. He refused and told Smith in a Nov. 26 letter: "You fail to address the overall issue of noncompliance with the technical specifications of the contract."
Smith did not return calls last week seeking comment.
Butkovitz asked whether the construction manager had adequately monitored the job, or may have "ignored" the contractor's "failure to supply materials and follow procedures." He requested that the city solicitor consider forwarding the matter to city or federal prosecutors "for further investigation."
In January, A.P. Construction sued the city for the $65,000 payment, plus interest. A.P.'s attorney, Christopher McCabe, declined to comment, saying the matter is in litigation.
On March 14, Butkovitz wrote airport CEO Mark Gale that the US Airways incident added "a sense of urgency to our requests" to make "needed repairs to Taxiway S."
Early reports said Flight 1702 had blown a tire. The National Transportation Safety Board is investigating. US Airways' latest statement refers only to a collapsed nosegear, with no mention of a blown tire. It may turn out the tire deflated after the nosegear collapse.
The city, the airport - and Butkovitz - agree there's no causal link between Taxiway S and the accident. Crew safely evacuated the 149 passengers.
In a statement Friday, US Airways said: "From our perspective, there aren't any current safety issues concerning Taxiway Sierra."
Aircraft move at slow speeds on taxiways, and at high speeds on runways during takeoff and landing.
"The primary significance of rutting is that the ruts hold water, which can reduce skid resistance at high speeds," said Peshkin, the pavement engineer. "But this was not a high-speed taxiway. Also if a rut holds water, the water turns to ice. You can't remove ice from a rut with a plow. There is a safety implication.
"You don't want rutting. If you have rutting, you want to find a cause and remove it," he added.