Hazard Above

How drones are controlled

By Alberto Cuadra and Craig Whitlock, Published June 20, 2014

Seven models of military drones are involved in the great majority of crashes. The loss of a link between the drone and the ground-control station is a prevalent cause of catastrophic failure. Most drones can operate autonomously for a large amount of time, but if contact is not recovered they will crash after spending their fuel.

Pilots rely on satellites to track drones

From takeoff until it leaves the line of sight, the drone is controlled with a direct data link from a ground-control station. When the drone leaves the line of sight, the ground-control station switches to a satellite link to control the aircraft. The drone also uses GPS to relay its position. If the communication link is lost, the drone is programmed to fly autonomously in circles, or return to base, until the link can be reconnected.

Pilots rely on satellites to track drones

From takeoff until it leaves the line of sight, the drone is controlled with a direct data link from a ground-control station.

Communications satellite

GPS satellite

Satellite antenna

Ground-control station

Target

When the drone leaves the line of sight, the ground-control station switches to a satellite link to control the aircraft. The drone also uses GPS to relay its position.

MQ-1 Predator

First flown in 1994, it later became the first weaponized drone. Designed to conduct surveillance with powerful cameras and sensors, it can be armed with laser-guided Hellfire missiles. It often stays aloft on missions for more than 20 hours at a time and can reach an altitude of 25,000 feet.

MQ-9 Reaper

The bigger, faster and more reliable successor to the Predator. It can fly as high as 50,000 feet and carry four Hellfire missiles, twice as many as the Predator. The Air Force expects to replace all its Predators with Reapers by 2018. The civilian version of the MQ-9 is called the Predator B.

MQ-5 Hunter

Originally developed in the 1990s, the Hunter features an unusual twin tail-boom design and is powered by two engines. Upgraded versions can carry Viper Strike munitions and climb to a ceiling of 20,000 feet.

MQ-1C Gray Eagle

The Army’s upgraded version of the Predator system, and the successor to the Army’s MQ-1 Warrior. It can carry four Hellfire missiles and stay aloft as long as 25 hours. Predecessor versions were the Warrior and I-Gnat.

QF-4 Phantom

Old F-4 fighter jets that have been modified and retrofitted into a drone for target practice. The remotely controlled aircraft is used as a target for missiles fired by other aircraft and to evaluate the effectiveness of various weapons systems.

RQ-4 Global Hawk

A high-altitude, reconnaissance aircraft that conducts missions as the U-2 spy plane. It can reach a ceiling of 60,000 feet and has a range of nearly 9,000 nautical miles. Its wingspan is comparable in size to a Boeing 757’s.

MQ-8 Fire Scout

A helicopter drone operated by the Navy, usually in support of Special Operations forces. It is designed to take off and land from ships at sea, but also has been deployed to Afghanistan. It can climb to a ceiling of 20,000 feet and has a range of about 110 miles.

Sources: Air Force, General Atomics Aeronautical Systems Inc., and Northrop Grumman Corp.

Part one: War zones

More than 400 large U.S. military drones have crashed in major accidents around the world since 2001, a record of calamity that exposes the potential dangers of throwing open American skies to drone traffic, according to a year-long Washington Post investigation.

Drone crash database

See the details behind 194 of the most severe drone crashes. About one-third of the crashes occurred in Afghanistan, but nearly one-quarter happened in the United States during test and training flights.