Military blames mechanical failure for runaway blimp

The military is blaming mechanical and design problems for a runaway Army blimp that broke free and captured the public’s attention last year.

“Overall, design, human and procedural issues all contributed to the incident,” Michael Kucharek, chief of integrated communications for the North American Aerospace Defense Command (NORAD) and U.S. Northern Command, said in a written statement on Friday.

In October, a blimp that’s part of a system known as JLENS broke free from its mooring in Maryland and drifted to Pennsylvania. Along the way, a cable attached to it left a path of damage, and its journey went viral on social media.

{mosads}The blimp, also known as an aerostat, broke free when there was a loss of pressure in its tail fins, Kucharek said.

When wind speed outside the blimp increases, the internal pressure also needs to increase. In this case, he said, internal pressure didn’t increase because the sensing device, called a pitot tube, malfunctioned.

“When the tail fin momentarily sagged, a lightning rod cable wrapped around the fin, tearing it,” he said. “As a result, the aerostat became unstable, and the increase in wind drag and subsequent loss of aerodynamic efficiency increased the tether tension to the point of breakage.”

The blimp was one of two that’s part of the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System, or JLENS. The blimps float 10,000 feet in the air and carry powerful radars that detect airborne threats.

The system was part of a three-year trial program at the Aberdeen Proving Ground in Maryland at the time of the incident.

After the incident, some lawmakers deemed the $2.8 billion program a waste and demanded answers from the Pentagon.

Congressional committees have not yet been briefed on the investigation, Kucharek said. Congress’s approval is needed to continue with the program.

If the program is allowed to continue, NORAD would need to assemble a new fire control aerostat, Kucharek said.

“Modifications to the inspection schedules, including the pitot tube, additional personnel, equipment changes and redesigns and additional training are all being examined or incorporated,” he said. “Future systems will have the necessary changes incorporated and risks assessed before they are sent aloft.”