January 30, 2012: The U.S. Air Force has stopped buying the RQ-4 Global Hawk UAV. Ten of the 31 Block 30 models ordered were cancelled. None of the planned Block 40 aircraft will be built. Global Hawk will remain in production, as the U.S. Navy is buying 68 of their MQ-4C BAMS (Broad Area Maritime Surveillance) model. Actually, the air force is interested in BAMS. While that may seem strange it makes perfect sense if you understand the problems the air force has been having with the RQ-4. While the RQ-4 has always been hailed as a revolutionary and successful system, most of the recon and surveillance jobs in the last decade were handled by the more reliable and popular Predator and Reaper UAVs. Meanwhile, the air force was having growing problems with the RQ-4.

Increasingly, the air force and the manufacturer (Northrop Grumman) of the RQ-4 have been 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 delayed the RQ-4 Block 30 cancellation it did not stop it. The air force was placated for a while when Northrop Grumman fixed some of the problems (some of which the manufacturer said don't exist, or didn't matter). The Block 30 was supposed to be good to go, but the air force was not convinced and decided that Block 30 was just more broken promises. Congress was also tired of all the feuding and being caught between Northrup lobbyists and exasperated air force generals. Then there was politician's decision to cut the defense budget over the next decade. Something had to go.

Meanwhile, the manned U-2 has continued to operate as expected and, despite its age, with predictable costs. Moreover, the U-2 carries a larger load than the RQ-4 and that means it can do more when it is up there. The U-2 also has its supporters in Congress. So the RQ-4 took a hit so the popular U-2 could keep flying for another decade or so.

You'd think the RQ-4 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 disagreed over what caused these problems. The air force blamed it on poor management. Northrop Grumman said it's all about dealing with complex technology. The air force pointed out that the RQ-4 was not high tech. The sensors often are but they are added to the aircraft after they came off the production line. Northrop Grumman continued to stonewall the air force and showed no signs of making any basic changes. Some air force procurement officials believed Northrop Grumman diverted resources to foreign customers, while taking advantage of the fact that there was no other supplier the air force could go to for long range UAVs.

There were sixteen of the RQ-4A ("Block 10") aircraft built, 14 for the U.S. Air Force and two for the U.S. Navy. The later models were the larger RQ-4B (block 20, 30, and 40). Production has been consistently behind what Northrop Grumman had earlier promised. The air force originally planned to buy over 40 Block 30s and wanted to get them faster, and with the reliability problems be fixed. That did not work out.

A year ago, the U.S. Air Force transferred its remaining seven early model (Block 10) RQ-4s to other government agencies. These UAVs began flying nearly a decade 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).

Things started off on a more promising note. 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.

Four 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 decade RQ-4s have flown over 55,000 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 had 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 than 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 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. But the U.S. Air Force is looking elsewhere.