Navy's unmanned combat aircraft flying under cloud of uncertainty.

• Author: Erwin, Sandra I.

The Navy expects to invest a growing share of its aviation research dollars in unmanned aircraft as it seeks to extend the reach and endurance of its carrier-based air wings.

The science behind unpiloted flying is well understood by now, after years of progressively more frequent deployments of drones by the U.S. military. Scientists have perfected technologies such as autonomous flying--which does not require a controller on the ground--and in-flight refueling of unmanned aircraft. They are now finding that the technology, although mature, is running up against policies that could hinder its progress. Rules that restrict independent UAV flying, experts contend, are expected to slow the expansion of unmanned aircraft.

"Making an unmanned vehicle fly is not a challenge. It's an airplane, and we understand those pretty darn well, whether they're large or small," said Rebecca Ahne, deputy chief technology officer of the Naval Aviation Enterprise, under the Naval Air Systems Com-mand, in Patuxent River, Md.

The NAE oversees the Navy's and Marine Corps' $40 billion worth of aviation programs, including 3,700 aircraft and 11 aircraft carriers.

Ahne said the naval aviation community, like its Air Force and Army counterparts, is comfortable operating remotely controlled aircraft, but it could be awhile before more advanced autonomous systems are seen taking off and landing on carrier decks.

'Technology issues are easy if we are just talking about flight," Ahne said in an interview "If it's a truly autonomous aircraft, are we comfortable with that, that it can avoid collisions" with other aircraft or with terrain? she asked. Ahne does not see any technological barriers to having combat aircraft flying autonomously, but she sees "lots of policy issues" that have to be resolved before engineers can continue to push the technology. "Whether we'll be allowed to do that [fly autonomously] certainly drives technology" she said. "Instead of truly autonomous, do we need a system that can alternate between autonomous and man in the loop?"

There are also well-known regulatory barriers that are imposed by the Federal Aviation Administration that limit unmanned aircraft flying in U.S. airspace. Safety concerns are magnified when it comes to the crowded deck of an aircraft carrier, where UAVs would have to share the congested airspace and deck area with manned aircraft and crews.

"The biggest challenges are control and communications," Ahne said. There is no...