January 8, 2012: Two years after extensive tests in the Middle East the U.S. Navy's customized RQ-4 Global Hawk UAVs is now operating with a carrier task force at sea. This navy version of the U.S. Air Force RQ-4 is called BAMS (Broad Area Maritime Surveillance). Circling above the task force at 22,500 meters (70,000 feet), BAMS is monitoring sea traffic off the Iranian coast and the Straits of Hormuz. Anything suspicious is checked out by carrier or land based aircraft, or nearby warships. The BAMS aircraft fly a 24 hour sortie every three days. The first production BAMS will be available in six months, and these models will begin entering service in three years.
In 2009, the BAMS test consisted of 60 flights and over 1,000 hours in the air. The flights were over land and sea areas, even though the UAV sensors are designed mainly to perform maritime reconnaissance. U.S. Air Force Global Hawk maintenance personnel assisted the navy in tending to the navy RQ-4 while it was on the ground, and for landings and takeoffs. The UAV was operated by navy personnel back in the United States at Patuxent River Naval Air Station. A year earlier, the navy began training four of its personnel (three P-3 pilots and one civilian) to operate RQ-4s. The four navy operator trainees were in an accelerated course (four months instead of five) and were available to help fly U.S. Air Force RQ-4s before the navy RQ-4s test model became operational in 2009. The air force could use the help, as the RQ-4s have been in the air for 30,000 hours over the last decade. The rate of use is accelerating. The navy plans to buy 20 BAMS and 117 P-8As to replace 250 P-3Cs. This replacement is supposed to be complete in about a decade. The new surveillance aircraft provide more information over a wider area.
The P-3 replacement, the P-8A is expected to complement BAMS. Although the Boeing 737 based P-8A is a two engine jet, compared to the four engine turboprop P-3C it is replacing, it is a more capable plane. The P-8A has 23 percent more floor space than the P-3, and is larger (118 foot wingspan, versus 100 foot) and heavier (83 tons versus 61). Most other characteristics are the same. Both can stay in the air about ten hours per sortie. Speed however is different. Cruise speed for the 737 is 910 kilometers an hour, versus 590 for the propeller driven P-3. This makes it possible for the P-8A to get to a patrol area faster, which is a major advantage when chasing down subs spotted by sonar arrays or satellites. However, the P-3 can carry more weapons (9 tons, versus 5.6). This is less of a factor as the weapons (torpedoes, missiles, mines, sonobouys) are pound for pound more effective today and that trend continues. Both carry the same size crew, of 10-11 pilots and equipment operators. Both aircraft carry search radar and various other sensors.
The 737 has, like the P-3, been equipped with bomb hard points on the wings for torpedoes or missiles. The B-737 is a more modern design and has been used successfully since the 1960s by commercial aviation. Navy aviators are confident that it will be as reliable as the P-3 (which was based on the Electra civilian airliner that first flew in 1954. Although only 170 were built, plus 600 P-3s, about 20 Electras are still in service). The Boeing 737 first flew in 1965 and over 5,000 have been built. The P-8A will be the first 737 designed with a bomb bay and four wing racks for weapons.
The U.S. Air Force and Navy are buying the B version of the RQ-4 Global Hawk UAVs, at a cost of over $60 million each. This version is larger (wingspan is 5 meters/15 feet larger, at 42.2 meters/131 feet, and it's nine percent longer at 15.5 meters/48 feet) than the A model, and can carry more equipment. To support that, there's a new generator that produces 150 percent more electrical power. The RQ-4 has a range of over 22,000 kilometers and a cruising speed of 650 kilometers an hour.
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, which more than double the cost of the aircraft. These "spy satellite quality" sensors (especially AESA radar) are usually worth the expense because they enable the UAV, flying at over 20,000 meters (62,000 feet), to get a sharp picture of all the territory it can see from that altitude. The B version is supposed to be a lot more reliable. Early A models tended to fail and crash at the rate of once every thousand flight hours.
The maritime RQ-4 is seen as the ultimate replacement for all manned maritime patrol aircraft. The P-8A will probably be the last manned naval search aircraft. Some countries are using satellite communications to put the sensor operators who staff manned patrol aircraft on the ground. Some nations propose sending aircraft like the P-3 or P-8 aloft with just their flight crews, having all the other gear operated from the ground. This enables the aircraft to stay in the air longer and carry more gear.