The F-35 Joint Strike Fighter will not get its combat capability package until late 2017, putting the long-delayed aircraft another four months behind schedule, according to a top U.S. General charged with overseeing the program. In a written testimony to the House Armed Services subcommittee on tactical air and land forces Wednesday, Gen. Christopher Bogdan cited software testing issues on the newer 3F software as the reason for the most recent delays to $1.5 trillion program, specifically the knock-on-effect of past delays on older versions of the software.

In order to fix the issues, Bogdan established what he called the “Red Team,” made up of experts from the Navy, Air Force and outside the Pentagon. The Red Team has already begun its study and will report back in about a month, Bogdan told reporters after the hearing.

“We brought them together and we’re sending them down to Lockheed to try to figure out, do we have the root cause analysis right on these problems? Are we going after the right issues?” Bogdan said, according to a Defense News report. “Because it’s very easy to just make a fix to the software, but if you don’t fix the fundamental issues going on those fixes only will last so long and they will pop up again.”

According to additional testimony from Director of Operational Test and Evaluation Michael Gilmore, the previous problems with software were “so significant that the program could not continue flight test,” he wrote.

The newest revelation comes just a month after the U.S. Department of Defense released a  report outlining ongoing software issues embedded in the F-35’s design. Dozens of problems were mentioned, including technical problems “in fusion, electronic warfare, and weapons employment resulting in ambiguous threat displays, limited ability to respond to threats, and a requirement for off-board sources to provide accurate coordinates for precision attack.”

Two weeks ago, it was discovered that a problem with the aircraft’s radar software meant that it had to be turned off then on again in order to reset the equipment.