We don't cover military drones here, but I thought I'd make an exception for this excellent LA Times article, which shows that the pros have as much trouble with their UAVs as we amateurs do!
"Thirty-eight Predator and Reaper drones have crashed during combat missions in Afghanistan and Iraq, and nine more during training on bases in the U.S. — with each crash costing between $3.7 million and $5 million. Altogether, the Air Force says there have been 79 drone accidents costing at least $1 million each."
"At least 38 drones are in flight over Afghanistan and Iraq at any given time."
"At least one drone crashed because it had no fuel gauge, and the aircraft ran out of fuel. In another crash, investigators cited a design flaw: The "kill engine" switch was located next to the switch to lower the landing gear, and a ground-based pilot confused the two."
""These airplanes are flying 20,000 hours a month, OK?" said retired Rear Adm. Thomas J. Cassidy Jr., president of the aircraft systems group at General Atomics Aeronautical Systems in San Diego, which makes Predators and Reapers. "That's a lot of flying," Cassidy said. "Some get shot down. Some run into bad weather. Some, people do stupid things with them. Sometimes they just run them out of gas."
"On Sept. 13, a pilot inside a ground station in Nevada lost video and data links to a Reaper over Afghanistan. As it was about to exit Afghan airspace and crash, an F-15 pilot was ordered to shoot it down and ground troops recovered the wreckage to keep top-secret technology out of insurgents' hands."
"After a Predator crashed during a landing at Kandahar air base in March 2007, investigators faulted the Predator system for a "lack of visual cues" to help pilots understand the position of a plane flying half a world away. The pilot in Nevada misjudged the drone's altitude, the investigative report said.
The Predator that ran out of fuel over Iraq had a leak, but there was no gauge to warn the pilot, an Air Force crash researcher said. And a pilot trainee at Creech Air Force Base in Nevada crashed a Predator by hitting the "kill engine" switch instead of the adjacent landing gear switch, according to an investigative report.
Some ground control stations, where pilots and camera operators sit, still have 1990s-era text-based computer systems. Pilots have to type function and control commands rather than clicking on icons.
"There's a control delay between typing something and having it actually happen on the airplane," said Gregg Montijo, a contractor who trains drone crews. "When the heat is on, sometimes guys will type something in, then type it again real quickly. They'll confuse the computer and get the wrong display and get into a vicious cycle."