On April 25th, the U.S. Navy's new maritime patrol aircraft, the P-8A Poseidon, took its first flight. The first production P-8A won't join the fleet for another four years, It was two years ago that the navy officially named the new aircraft the P-8A and put development into high gear. Back then, it was hoped that the first P8As would enter service by 2010. But the usual procurement politics and delays have changed that. The initial optimism was partly based on the fact that the P-8A is basically a militarized version of the popular Boeing 737 airliner.
Five years ago, the navy was still considering a competing design that, like the current P-3, used props, instead of jets. Propellers were still a contender because maritime patrol aircraft, when looking for submarines, spend a lot of time at low altitudes (200 feet or so), moving slowly, in order to get the most out of their sensors. But jet engines operate best at high altitudes. Most sailors who serve on P-3s, know what it's like to fly on a jet, and have always been big supporters of propeller driven patrol aircraft. But the Boeing engineers knew that a 737 could do the job. They came up with a clever plan to change the minds of the thousands of sailors currently flying P-3s. Boeing equipped a 737 with the equipment found in a P-3 (some countries were already using navalized 737s as patrol aircraft), and went around to naval bases, where P-3s were stationed, and took P-3 crews for a ride on the their P-8 mockup. They spent most of the time at low altitudes. The P-3 users were convinced and, thanks to the Internet, the word got around quickly. This P-8 mockup and all those naval personnel who flew around in it, was one of the reasons for the optimism over how soon the P-8A would be ready to operate.
Development problems aside, although the Boeing 737 based P-8A is a two engine jet, compared to the four engine turboprop P-3, 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 is different. Cruise speed for the 737 is 910 kilometers an hour, versus 590 for the 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 30 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.
Meanwhile, the navy is already changing the specifications for the P-8A, partly to insure that the aircraft can rapidly adopt to future technical changes, which is navy is certain will be rapid and unending.