An unmanned experimental hypersonic military aircraft called the Waverider broke apart over the Pacific Ocean seconds into a test flight due to a faulty control fin, the U.S. Air Force said on Wednesday.

The problem with the fin was identified 16 seconds after a rocket booster on the X-51A aircraft was ignited to increase its speed in a test flight on Tuesday morning, the Air Force said in a statement.

Fifteen seconds later, when the X-51A separated from the rocket booster, it lost control due to a "faulty control fin," the statement said. The 31 seconds of flight fell far short of the military's goal for the X-51A to fly for five minutes.

The aircraft broke apart immediately and fell into the Pacific Ocean near Point Mugu northwest of Los Angeles, said Daryl Mayer, a spokesman for the 88th Air Base Wing at Wright-Patterson Air Force Base in Ohio.

The Waverider was designed to reach speeds of Mach 6 or above, which is six times the speed of sound and fast enough to zoom from New York to London in less than an hour. The military has its eye on using the Waverider program to develop high-speed cruise missiles.

The cost of the experimental aircraft has not been disclosed because many details of the program are classified.

This was the third of four X-51A aircraft built for the military. The Air Force said in a statement that one of the aircraft remains and that a decision has not been made "when or if that vehicle will fly at this time."

Pratt & Whitney Rocketdyne designed the X-51A's "Scramjet" engine, which uses the forward motion of the craft to compress air for fuel combustion, according to a description of the project from the military.

"It is unfortunate that a problem with this subsystem caused a termination before we could light the Scramjet engine," Charlie Brink, X-51A Program Manager for the Air Force Research Laboratory, said in a statement.

"All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives," Brink said.