By the time the Boeing P-8 Poseidon becomes operational in 2012, 50 years will have passed since its predecessor the Lockheed P-3 Orion entered service; 30 years since the US Navy began looking for a replacement; and almost 20 years since P-3 production ended.
One of the true classics, the P-3 has proved hard to replace.
Beginning life in 1958 as a modification of Lockheed's Electra turboprop airliner, the P-3 Orion is being replaced five decades later by another derivative of a commercial aircraft - this time Boeing's immensely successful 737. It's a transition to jets that's long overdue, some would say, but had history turned out differently the P-3 would still have a long life ahead of it.
The US Navy tried to replace the P-3 with the P-3 in 1987, when it came up with the concept of an upgraded P-3G and tried to get industry to compete to build it. Only Lockheed bid, so the Navy opened its Long Range Air ASW Capable Aircraft (LRAACA) competition to commercial aircraft derivatives. Boeing offered a modified 757, and McDonnell Douglas a P-9 derivative of its proposed propfan-powered MD-91. But the Navy in 1988 picked Lockheed's P-7 - essentially a new P-3 powered by new T407 turboprops - saying it offered lower cost and risk.
Two P-7 prototypes were to be delivered in 1992, but then it all started go wrong. It was a fixed-price development programme and the requirements kept changing. The weight went up. The costs went up. And in 1990 the US Navy terminated the P-7 programme and Lockheed wrote off $300 million in cost overruns. To add insult to injury, two years later the Navy cancelled the Boeing Update IV avionics package for the P-3 and P-7.
It was a blow that was felt outside the USA, for the UK had intended to replace RAF Nimrod MR2s with the P-7. In its place the UK in 1993 launched the Replacement Maritime Patrol Aircraft competition. Lockheed pitched in with the Orion 2000, a new P-3 with AE2100 engines. British Aerospace proposed the refurbished, re-engined and optimistically named Nimrod 2000.
The RMPA contest turned into a bloody "save Britain's aerospace industry" battle that Lockheed, having just sold C-130Js to the RAF, stood little chance of winning. In 1996 the Nimrod 2000 was declared the winner, becoming the MRA4, and proceeded to turn into a real mess, forcing the contract to be renegotiated and reduced to just 12 aircraft expected to be delivered six years late in 2009.
Lockheed still believes, had the UK selected the Orion 2000, the US Navy would have followed suit. But when it came around to looking again for a P-3 replacement, the Navy from the outset included commercial derivatives in the competiton. Boeing proposed a modified 737-800. Lockheed held talks with EADS on an A320 derivative, but the idea died - as did BAe's hopes of offering the Nimrod MRA4. Instead Lockheed proposed the Oriion 21 - a refurbished P-3 with new wing and PW150 engines.
This time round the Navy went with the jet, selecting Boeing's P-8 as its Multi-mission Maritime Aircraft and setting the stage for the eventual extinction of the P-3 - although it is not yet the end of the saga. The Poseidon is scheduled to enter service in 2013, but the US Navy will continue to operate the Orion beyond 2020 and international customers beyond 2030.