WASHINGTON, D.C. -- A government report raised new safety concerns over widespread use of unmanned aircraft by police departments around the country, Local 2 Investigates reported on Monday.

"The concern is that you could lose control of that aircraft and it could crash into something on the ground or, in fact, it could crash into another air vehicle," said Gerald Dillingham, director of civil aviation for the Government Accountability Office.

He spoke with Local 2 Investigates this week from Washington, after finishing a 73 page report on police departments across the country attempting to use drones for patrols and SWAT team actions.

Dillingham said, "There are probably over a dozen police departments that have talked to FAA about it."

Local 2 Investigates had cameras rolling in November when the Houston Police Department became the first police department to test unmanned aircraft. Police officers and other dignitaries attended, but the official invitation stated, "No Media Allowed."

Officers gathered around as an unmanned aircraft zoomed off a launch pad and began flying around a rural area of Waller County, some 70 miles away from Houston.

The GAO report points out several concerns as more police departments and commercial ventures try to gain more widespread use of this technology, which has been reserved for military and battlefield uses in the past.

The report states that turbulence and other dangerous conditions that would keep pilots from flying manned aircraft for their own safety may not deter police from launching unmanned aircraft right into danger.

"The difference is, if you're onboard the aircraft, you can tell that you're into turbulence and you can maneuver to get the plane or aircraft out of the turbulence," said Dillingham. "But if you're using a UAV and there are no sensors aboard, you don't really know that and, again, if you lose that communication link as a result of that turbulence, or for any other reason, then you have an aircraft that is not in control and can in fact crash into something on the ground or another aircraft."

The GAO cited data from the Defense Department and NASA in several years of testing drones. In 199 crashes of unmanned aircraft on battlefields in Iraq and Afghanistan, 65 percent were caused by mechanical failures. The report notes this is common with a new technology.

Seventeen percent were caused by operator error and 12 percent were listed as "causes unknown."

The Pentagon reported that unmanned aircraft crash twice as often as manned military aircraft, but the rates get better as operators get more experience.

Another concern with more widespread use of unmanned aircraft is the communication link that controls the aircraft using radio frequencies is vulnerable to intentional or accidental interference that could lead to a loss of control and an accident. The same set of circumstances got the blame for a 2006 crash in Nogales, Arizona, but then the operator was listed as failing to correct the "lost link."

Houston police say drones are still being studied with FAA and they are far from beginning patrols with the aircraft. In response to a question from Local 2 Investigates, Assistant Police Chief Vicki King e-mailed, "We are working with the FAA and other grant resources to identify the funding necessary to field test the technology. We feel that it holds significant promise, but we must balance this research effort against other public safety priorities."

The Federal Aviation Administration told GAO it has $4.7 million budgeted through fiscal year 2009 to research drones for police and private use. The Defense Department expects to spend $7 billion on drone testing through the year 2013.

The GAO report concludes the government is not staying ahead of nationwide demand, which is projected to peak in the year 2012.

The current pace of government testing would be eight years late, catching up with demand in 2020, according to the GAO report.