Failure suspected in runaway blimp's emergency-landing system

November 4, 2015

By Sebastian Sprenger

The Army surveillance blimp that broke free from its tether north of Baltimore last week made its way all the way to northeast Pennsylvania because of the likely failure of safety features designed to ground the craft quickly, Inside Defense has learned.

Problems with an “emergency flight termination system” were reported just hours after the football-field sized aerostat, known as the Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System, broke free from its mooring station around noon on Oct. 28 at Aberdeen Proving Ground, MD, internal Army assessments show. One such feature was supposed to cause “rapid deflation” of the blimp, aided by what a source said was a mechanism to “blow a large hole” into the hull to hasten the escape of helium and air.

While the system activated 20 seconds after the tether broke, “initial indications” are that it failed to work properly, the report states.

Sources said the blimp's tether snapped when personnel were in the process of bringing it down because of high winds. Sensors monitoring pressure on the tether had indicated that the weather's pull was too strong. While lowering the craft, which usually flies at 10,000 feet, the connection broke when the blimp was at 6,000 feet, sources said.

According to a Northern Command statement early that afternoon, the blimp proceeded to soar to 16,000 feet and was accompanied by fighter airplanes during its escape. Dragging its still-attached tether across the ground, the aerostat knocked out power for tens out thousands of people in its path before coming to a halt near Moreland Township, PA.

The service has said it would not answer questions about the episode pending the conclusion of a “thorough and complete investigation,” according to Army spokesman Dov Schwartz. Since the accident, contractor Raytheon has referred questions about it to the military. A company spokeswoman did not return a reporter's phone call seeking comment on any failure of emergency-safety mechanisms.

Program officials have previously said the JLENS tether is virtually unbreakable, and safety features were in place to deal with the highly unlikely scenario of a loose blimp.

The Army investigation will determine how to proceed with a two-year demonstration of the system, sponsored by U.S. Northern Command, that was supposed to last until 2017. The blimps are equipped with sensors that can scan a radius of hundreds of miles for incoming cruise missiles.

“Out of an abundance of caution, the remaining JLENS aerostat has been lowered and secured,” command spokeswoman Maj. Beth Smith wrote in a statement for this article. “Future actions regarding the JLENS exercise will be made following the conclusion of the investigation.

Military officials began flying the first of two blimps comprising one JLENS orbit last December. Winter weather at that time allowed far fewer test flights than officials had anticipated, Inside the Army reported in March. Cold weather also delayed the construction of a ground pad for the second aerostat.

The accident last week has the Army miffed because it happened as part of a program that the service had planned to kill years ago. Officials are privately complaining that the system now is being portrayed as a fielded program of record when it amounted to little more than a prototype kept alive by various interest groups in the military and in Congress.

“Most of the testing wasn't done,” said one source, referring to a regimen of mandatory tests that acquisition programs normally must undergo. Software for the system also wasn't completed, the source said.

Options for the Army following the JLENS episode range from reconstituting the orbit with one of two JLENS blimps still in storage to canceling the project and demilitarizing the components. Lawmakers will have a chance to intervene when they craft a defense spending bill for fiscal year 2016 in the weeks ahead.