An RQ-4 Global Hawk conducts tests over Naval Air Station Patuxent River, Md. A Global Hawk crashed near Patuxent on June 11. (Erik Hildebrandt / Northrop Grumman via Navy)
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A Fire Scout like this one crashed into the Mediterranean on Dec. 13 while heading back to frigate Robert G. Bradley. (Kelly Schindler / Navy)
Sailors cut short an MQ-8B Fire Scout surveillance mission in the Mediterranean on Dec. 13 when the unmanned helo entered icy conditions.
But the craft never made it back from Africa's northern coast.
Before it reached the frigate Robert G. Bradley, the Fire Scout crashed into the water, said Cmdr. Marc Boyd, spokesman for Naval Forces Europe/Africa. Shortly before the crash, "debris" had fallen from the UAV. It was unclear what constituted debris.
The UAV wasn't recovered, and the mishap marked the fourth time in a year the Navy had lost a large-scale unmanned aircraft.
In the other three mishaps in 2012, two large UAVs were destroyed and the other was seriously damaged.
Officials are looking to glean lessons learned from this recent spate of incidents, especially in light of the fact that the service is dealing with new technology.
"Let me start with what's new: They're here," said Rear Adm. Brian Prindle, commander of the Naval Safety Center.
In 2012, the first MQ-4C Triton rolled off the production line, giving the Navy its first Broad Area Maritime Surveillance UAV built from the ground up. Four MQ-8B Fire Scouts deployed on the frigate Klakring, the largest Fire Scout detachment to date, and the X-47B started carrier compatibility tests.
"Unfortunately, we've logged our first, second and third Class Alpha [mishaps] for unmanned aerial systems for [fiscal 2012]," Prindle added.
The fiscal year ended Sept. 30, so the December incident will count for fiscal 2013. There were no UAV Class A mishaps in 2011, although a Fire Scout was shot down over Libya in 2011.
Here's a closer look at the three fiscal 2012 incidents, which represent three of the Navy's 13 Class A mishaps that year:
• On March 31, an MQ-8B Fire Scout was intentionally ditched into the sea off Africa's western coast after a landing system failed to engage after several attempts. It was recovered.
• On April 6, a second Fire Scout crashed in Afghanistan because of an issue with its navigation system during a mission. It was a complete loss, but investigators recovered some parts of the unmanned helicopter for analysis. Those two crashes temporarily suspended Fire Scout operations.
• On June 11, an RQ-4 Global Hawk in the BAMS program had a mechanical failure and crashed into a swampy area near Naval Air Station Patuxent River, Md.
As for the December incident, Naval Air Systems Command is investigating. The crash also briefly suspended flight operations on the frigate, though that suspension is over.
Prindle said that in examining these crashes, the Navy should look to the Air Force for guidance.
"This present year, they lost seven Predators and three Reapers, so they're not doing particularly well, either," he said at September's Tailhook Convention in Sparks, Nev.
Even so, the Air Force has seen significant drops in its UAV mishap rates.
Aviation mishap rates indicate how many mishaps occur for every 100,000 flight hours. Air Force MQ-1 Predators dropped from 113 Class A mishaps for every 100,000 flight hours in 1997 to 3.7 in fiscal 2012. The MQ-4 Global Hawk, the older brother of the Navy's Triton, dropped from a 383 mishap rate in 1998 to 22 in 2012. Meanwhile, the MQ-9 Reaper went from 63 in fiscal 2006 to 2.5 in 2012.
Mishap rates for UAVs in the Navy are not readily available.
"One major reason is that we do not have enough historical flight hours on them yet to weave them effectively into the manned mishap stats. DoD may require us to do so as early as next year," according to a Naval Safety Center briefing obtained via a Freedom of Information Act request.
The safety center later said Fire Scout mishap rates are tracked, and that after only 1,339 flight hours, its mishap rate would be calculated at 149 for every 100,000 flight hours. The tracking period spanned October 2009 through October 2012.
In that period, manned aircraft logged nearly 3.6 million flight hours, for a 1.18 mishap rate.
The MQ-4, a modified Global Hawk, does not meet operational requirements for NAVAIR to collect flight data. Smaller UAVs, like the ScanEagle, also are not tracked.
A trend appeared to emerge with Air Force mishaps. After about eight years of operating a particular aircraft, the mishap rates would drop significantly. So one thing Navy officials may need is time and more flight hours.
Air Force officials said improvements in operator training and design upgrades also made the aircraft safer.
NAVAIR has developed safety measures aimed at improving the Navy's emerging UAV fleet. In general, their efforts focus on the mechanical and engineering issues all types of aircraft face, plus the issues created by remotely piloting an aircraft from a ground control station.
In 2009, the Navy included emergency measures for unmanned systems in the Naval Air Training and Operating Procedures program, the how-to manual for naval aviation. Like manned aviation, the NATOPS UAV policies have specific procedures for every aircraft. But for unmanned systems, they also address the loss of data link between the ground station and aircraft, and the loss of communication between the operator and local air traffic control, said Rich Adams, chief engineer for the unmanned aircraft NAVAIR airworthiness office.
For unmanned systems, the safety program focuses on aircraft design, research, testing, evaluation, maintenance, servicing, operations and other issues, Adams said.
Like their manned counterparts, unmanned aircraft mishaps fall under the A, B and C classes, based on the damage of the incident. With unmanned systems, however, a Class A is an incident in which the damage is $2 million or greater. For manned aircraft, a Class A also includes cases where there is a fatality or a destroyed aircraft, a safety center spokeswoman said.