The order is the USN's largest to-date for unmanned aircraft and could make it the biggest customer for the RQ-4-series, potentially topping the USAF's contract for 53 of the high-altitude, long-endurance surveillance systems.
The USN first planned to award a BAMS contract in 2005, but delayed the competition for three years to continue to refine the concept. In the interim, Northrop delivered two RQ-4Bs to the USN with a modified sensor package to conduct an ongoing series of maritime demonstrations.
The first BAMS-configured RQ-4N aircraft will fly in 2011 and the first squadron will enter service in 2014. The USN wants the BAMS fleet to sustain a constant surveillance vigil over five maritime and littoral zones spread across the world, with each zone measuring 3,700km (2,000nm) across.
Northrop's BAMS aircraft will team with the 108-aircraft Boeing P-8A Poseidon fleet to replace roughly 225 ageing Lockheed P-3C Orions over the next decade. The P-8A will be mainly used to hunt for submarines, while the RQ-4N will scan the ocean's surface for suspect vessels.
The maritime role will pose a new challenge for the agility of the RQ-4, which normally remains perched at high-altitude. The USN will require the aircraft to descend to low altitude to positively identify particular vessels. The RQ-4 crews must balance altitude changes with the demand for constant high-altitude surveillance and mission endurance.
For Northrop, the BAMS award paves the way for the first export sale of the RQ-4 to Australia, which has already invested about $15 million to join the USN's programme. More export orders could soon follow in the Pacific region, with Singapore and South Korea among the most interested parties.
The BAMS contract will also allow Northrop to introduce an all-new sensor package for the RQ-4 Block 20 airframe. For the aircraft's radar, Northrop passed over Raytheon's active array and chose a new in-house system called the Multi-Function Active Sensor (MFAS).
"We think that the sensors, and this sensor in particular, provided what we felt exceeded the navy's requirements," said Bob Wood, Northrop's BAMS capture lead, speaking to reporters via teleconference call on 23 April.
The RQ-4N also will feature the Sierra Nevada Merlin electronic support measures (ESM) suite, which replaces the Telephonics LR-100. The BAMS aircraft also includes the Raytheon Multi-spectral Targeting System (MTS-A), an electro-optical and infrared camera. Aurora Flight Sciences remains a structural supplier on BAMS and Rolls-Royce will continue to deliver the RQ-4's standard AE2100 engine.
Northrop's victory gives it the three largest UAS programmes of record in the USN budget, including BAMS, UCAS-D and the RQ-8 Fire Scout unmanned helicopter. It also continues the company's remarkable streak of three straight major contract victories. Last August, the USN awarded Northrop a contract to develop the X-47 to be the unmanned combat aircraft system-demonstrator (UCAS-D). On 29 February, Northrop also won the KC-X tanker competition, which remains in limbo pending a protest decision due in June by the Government Accountability Office (GAO).
In all three races, Northrop's bid trumped a competing offer made by Boeing. The BAMS contract attracted a Boeing offer based on an optionally-manned Gulfstream G550 and a Lockheed Martin/General Atomics bid based on the Mariner, derived from the Predator B airframe.