April 16, 2012: The U.S. Navy has grounded its 14 MQ-8B Fire Scout helicopter UAVs (unmanned aerial vehicle) after one crashed in Afghanistan (on April 6^th) and another operating from a ship (on March 30^th) was ditched (and later recovered) in the sea when part of its landing navigation system failed (preventing a safe landing on the ship). These were the first MQ-8Bs lost due to operational causes. One was shot down over Libya last year. The navy will keep its MQ-8Bs grounded until it is certain that the two recent crashes were not caused by some problem common to all these UAVs.

In the last two years eight MQ-8Bs have flown nearly 2,000 hours, most of it in Afghanistan (from a land base). In 2011, two more MQ-8Bs were sent to sea with a frigate in the Mediterranean and one was lost over Libya last June. A Fire Scout detachment consists of two UAVs and 22 personnel (four pilots, three sensor operators, and 15 maintainers). The navy is now sending more MQ-8Bs to sea.

The 1.5 ton Fire Scout is based upon the Schweitzer 333 unmanned helicopter, which in turn is derived from the Schweitzer 330 commercial lightweight manned helicopter. Fire Scout has a payload of 272 kg (600 pounds), a cruising speed of 200 kilometers an hour, max altitude of 6,100 meters (20,000 feet), and endurance of eight hours. The U.S. Navy plans to acquire another 160 MQ-8Bs. The three (now two) in Afghanistan were being operated by contractors.

Some 20 percent of the air force Predator and Reaper UAVs have been lost to accidents. Everyone wants to make UAVs more reliable and reduce the loss rate (an accident causing destruction, or at least a million dollars of damage, per 100,000 flight hours). The rate for its MQ-1 Predators is down to about 5. Although this is twice the rate of manned fighter aircraft (like the F-15 or F-16) and four times the rate of the old but very reliable B-52, it's better than that of single engine private aircraft (8). Reapers have a rate of 5.4.

Only a few years ago the loss rate for the 1.1 ton MQ-1 Predator was 30. The 4.7 ton larger MQ-9 Reaper had a loss rate of about 15 two years ago, after four years in service. It was a decade ago that the MQ-9 made its first flight. The Predator has been in action since the late 1990s. The design and operation of the MQ-9 learned much from the experience of the MQ-1.

Unmanned aircraft have always had a much higher loss rate, which is largely the result of not having a pilot on board and not doing all that could be done to compensate for that. Older model UAVs had much higher rates. The 1980s era RQ-2A Pioneer had an annual rate of up to 363 per 100,000 hours. Despite that, the RQ-2 proved very useful during the 1991 Gulf war.