Earlier this year, the U.S. Air Force transferred its remaining seven early model (Block 10) RQ-4 Global Hawk UAVs to other government agencies. These UAVs began flying eight or so years ago and each has spent, on average some 3,000 hours in the air. Some have spent over 7,000 hours in the air, while others have mostly stayed on the ground. On average, these Block 10 aircraft flew once a week. But some 90 percent of hours flown were in combat operations. Subsequent models (Block 20, 30 and 40) had greater carrying capacity and reliability. Many payloads (various sensors) are designed for the larger models. But the Block 10 is still useful for civilian missions (disaster monitoring, border patrol and all sorts of research).
Meanwhile, the air force and the manufacturer of the RQ-4 (Northrop Grumman) continue feuding over design, cost and quality control issues. The latest issue was the unreliability of the new Block 30 models. This renewed Department of Defense threats to cancel the program. But manufacturer Northrop Grumman lobbyists have made sure the key members of Congress knew where Global Hawk components were being built, and how many jobs that added up to. While that saved the RQ-4 from cancellation, it did not stop the complaints. The air force was placated this time when Northrop Grumman fixed the problems (some of which the manufacturer said don't exist, or don't matter). The Block 30 is supposed to be good to go now, but the air force won't be convinced until the new Global Hawks perform as advertised for several months. Thus it won't be until the end of the year that Block 30 birds will be seen as reliable, or just more broken promises.
You'd think this aircraft would be somewhat perfected by now. Development of the RQ-4 began in the 1990s, as a DARPA research project. By 2006, per-aircraft costs were 25 percent over the original price. By 2007, production schedules had slipped as well. The air force and Northrop Grumman disagree over what has caused these problems. The air force blames it on poor management, Northrop Grumman says it's all about dealing with complex technology. The air force points out that the RQ-4 is not high tech. The sensors often are, but they are added to the aircraft after they come off the production line. Northrop Grumman continues to stonewall the air force, and shows no signs of making any basic changes. Some air force procurement officials believe Northrop Grumman is diverting resources to foreign customers, while taking advantage of the fact that there is no other supplier the air force can go to for long range UAVs. The new General Atomics Predator C (similar to, but smaller than, the RQ-4) may change Northrop Grumman's mind down the road, but is not seen as an immediate threat.
There were sixteen of the RQ-4A ("Block 10") aircraft, 14 for the U.S. Air Force and two for the U.S. Navy. The later ones were the larger RQ-4B (block 20, 30 and 40) models. Production has been consistently behind what Northrop Grumman had earlier promised. The air force has bought over 40 Block 30s, and wants to get them faster, and with the reliability problems be fixed.
The RQ-4 was still in development on September 11, 2001, but was rushed into action. The first production RQ-4A was not delivered until August, 2003. Although the RQ-4 could stay in the air for up to 42 hours, all of them had only amassed about 4,000 flight hours by 2004. But most of those 4,000 hours, which were originally planned to involve testing of a new aircraft, were instead used to perform combat missions. Global Hawk also got to fly under difficult conditions, something an aircraft still being developed, would not do.
Three years ago, an RQ-4A Global Hawk made the first non-stop crossing of the Pacific, flying 12,000 kilometers, from California to Australia, in 23 hours. The Global Hawk has previously crossed the Pacific in several hops, but it always had the endurance to do it non-stop. In the last nine years, RQ-4s have flown over 50,000 hours, most of that combat missions, and many of them from Persian Gulf bases. The latest models can fly 20 hour missions, land for refueling and maintenance, and be off in four hours for another twenty hours in the sky. But the reliability issues with the Block 30 made the longer missions infrequent. Otherwise, the RQ-4 has been very reliable, with aircraft being ready for action 95 percent of the time. An RQ-4 can survey about 4,000 square kilometers an hour.
The U.S. Air Force has been buying them at the rate of five a year, at a cost of $35 million each for the basic aircraft. Include payload (sensors and communications) and development costs, and it averages over $120 million each. The B version is about ten percent larger (wingspan of 42.3 meters/131 feet, and 15.5 meters/48 feet long) than the A model, and can carry an additional two tons of equipment. To support that, there's a new generator that produces 150 percent more electrical power. The B version is a lot more reliable. Early A models tended to fail and crash at the rate of once every thousand flight hours, mostly because of design flaws. The first three RQ-4Bs entered service in 2006.
At 13 tons, the Global Hawk is the size of a commuter airliner (like the Embraer ERJ 145), but costs nearly twice as much. Global Hawk can be equipped with much more powerful, and expensive, sensors, than other UAVs. These sensors more the double the cost of the aircraft. The spy satellite quality sensors (especially AESA radar) are usually worth the expense, because they enable the UAV, flying at over 60,000 feet, to get a sharp picture of all the territory it can see from that altitude.
The air force has stationed a squadron of Global Hawks on the island of Guam. These undertake recon missions throughout the western Pacific. The U.S. Navy is also buying Global Hawks to perform maritime reconnaissance. As a result of that decision, Australia is likely to buy some as well, to monitor the vast stretches of ocean that surround the island continent. Germany is buying the RQ-4, and NASA uses two of them.