August 27, 2015: Since the 1990s military ISR (Intelligence, surveillance and reconnaissance) has come to be dominated by UAVs (Unmanned Aerial Vehicle). Now there is a trend to outfitting some manned aircraft to operate without human crews, or with them. The unmanned configuration has plenty of advantages, among them eliminating risk to the aircraft’s crew and the ability to switch crews without landing the aircraft. This eliminates the problem of crew fatigue during long duration flights or particularly intense missions.

However, there are some situations in which a manned ISR aircraft would be better. For example not all armed forces, or non-military organizations, like border patrol or environmental agencies, have use access to the expensive satellite bandwidth needed to transfer large quantities of sensor data from to human analysts on the ground. In those cases having human analysts on board is the solution. Then there are missions that might require landing in unusual places, or perform other tasks that are hard to do through remote controls or via software.

To serve this demand dual purpose (manned/unmanned) aircraft are appearing on the market. The American built DA42 Centaur OPA (Optionally Piloted Aircraft) was designed for military, intelligence, law enforcement and science based operations. It can fly either manned or unmanned, or in a hybrid mode, as needs dictate. The hybrid mode is one where the aircraft is operated remotely (from the ground) just like in the unmanned mode, though the human analysts and their equipment are in the aircraft itself.

The $4.5 million Centaur is based upon the Austrian built 1.4 ton DA42 Twin Star utility aircraft is designed to carry sensors in a detachable nose pod, underneath the fuselage or from wing hardpoints. Total sensor load is 360 kg (800 pounds).

Possible sensors include an electro-optical (EO) / infrared (IR) video camera, signals intelligence antenna, synthetic aperture radar, marine search radar, communications relay, transponder, LIDAR (Light Detection and Ranging) or hyper-spectral imager.

The conversion between piloted and unpiloted configuration, which includes exchanging the pilot’s seat for a robotic control rig, can be done in under four hours by two technicians.

Unmanned, the aircraft can fly for 24 hours with a 90 kg (200 pound) payload, or less time with up to 360 kg (800 pounds) payload, and range in excess of 3,700 kilometers. Top speed is 320 kilometers an hour with a cruise speed range of about 260 kilometers an hour. Centaur’s service ceiling is 5,500 meters (17,000 feet) when manned, but if unmanned, the aircraft can operate 50 percent higher mainly because it would not need the heavy and expensive oxygen system a crew would need at such altitude. The aircraft normally carries a pilot and up to three passengers.

The Centaur OPA, thanks to being powered by two turbocharged diesel engines, not only has very long flight endurance, but also has a very low-noise and low-infrared (IR) signature, which can be further reduced with purpose built modification kids, and which combined with the carbon-composite construction and relatively small size gives the aircraft limited stealth.

The plane is currently undergoing testing, and one was already bought by the Swiss Armasuisse military procurement agency, for use as a flying test bed for UAV and sensor technology.  --Adam Szczepanik