The U.S. Navy’s quest to open up new seagoing roles for unmanned aviation took another major step forward on May 22 with the first flight of the unmanned Northrop Grumman MQ-4C Triton high-altitude maritime surveillance aircraft from the company’s Palmdale, Calif., facility.

Coming close on the heels of the successful May 14 catapult test of Northrop’s X-47B Unmanned Combat Air System Demonstrator from the deck of a U.S. aircraft carrier, the first flight of the maritime patrol Triton marks the start of a test campaign aimed at entry-into-service in 2015. The 80-min. flight, conducted in restricted airspace near Edwards AFB, is the first of up to nine envelope expansion missions that will pave the way for more extensive systems flight tests at Naval Air Station Patuxent River, Md., later this year. The air vehicle, controlled by a team of Northrop and Navy personnel, reached 20,000 ft. in altitude.

The start of flight tests, though five months later than intended at last June’s rollout ceremony, marks a key milestone in the Navy’s long-term plan to modernize its maritime patrol capabilities. The two-pronged initiative, geared toward longer-range overwater surveillance as part of the renewed strategic focus on Asia-Pacific, will see the service’s aging P-3 fleet replaced by a combination of 117 Boeing P-8As and 68 MQ-4Cs. The most advanced variant of the Global Hawk yet developed, the MQ-4C has been in development since 2008 under the $1.16 billion Broad Area Maritime Surveillance (BAMS) contract. The Navy plans to buy 70 aircraft, including two test vehicles, for a total cost of $13 billion.

The May 22 flight is a timely boost for Northrop Grumman, which is battling its Air Force customer to keep the RQ-4B Global Hawk family alive. In a separate blow earlier this month, Germany also announced its decision to not proceed with the planned procurement of a fleet of Euro Hawk variants.

On the plus side, the start of MQ-4C test flights follows an announcement from Australia that it will formerly request cost, capability and availability information on the Triton. Northrop is optimistic that this will ultimately evolve into a procurement program, as Australia is also involved in development of the P-8A, and is widely expected to place a firm order for up to eight or more of the Boeing-built aircraft in 2014.

Australia intends to replace its Lockheed AP-3C with P-8As, but is considering the MQ-4C for its AIR 7000 Phase 1B program to acquire a high-altitude, long-endurance UAV for maritime patrol and other surveillance missions. However, the Australian Defense Ministry makes it clear that a letter of request for information on the Triton “does not commit Australia to the acquisition of the MQ-4C.” Another nation also in the process of acquiring the P-8, India, has also shown interest in the MQ-4C.

SDD-1, the first of two unmanned aircraft ordered under the BAMS systems development and demonstration (SDD) contract, will be joined by SDD-2 in two to three months, says Mike Mackey, Northrop’s Triton unmanned air system deputy program director. A third development MQ-4C, funded by Northrop, will also be ferried to Patuxent River to join the initial pair of test aircraft in early 2014. “It will be used for electro-magnetic interference type work and augment the testing done by SDD-1 and -2,” Mackey says. Flights during the first phase will be every seven to 10 days, with the duration of each gradually increasing until the latter few will last between 8 and 12 hr.

The start of flight testing was delayed by issues related to software development for the aircraft’s vehicle integrated mission management computer (IMMC) system, and by modifications to the flight control surfaces. “We took a regimented and strong systems engineering approach to those,” says Mackey, who adds the improved software in the IMMC has been “run through the lab and various systems-level testing to get to the level of maturity and reliability we wanted for first flight.” Simulations and wind tunnel tests also unearthed a potential control authority issue in a particular “corner” of the planned flight envelope, which on the MQ-4C will include a greater number of missions at lower and mid-altitudes than are flown by its Air Force counterpart. The mass-balance issue was resolved with a “bit of a redesign” of part of the aircraft’s V-tail ruddervators, Mackey says.

“An efficiency test program captures the right level of testing in the laboratory and through integrated round testing in order to reduce the risk of flight test and also reduce cost. Management reviewed the schedule and elected to postpone the first flight to better balance the overall cost, schedule and technical risk,” says Capt. Jim Hoke, the Navy’s Triton program manager. “A simple weight balance has been incorporated to address the potential ruddervator-coupled flutter vulnerability.”

“As we go through the first phase of tests we will go through various altitude and weight profiles to demonstrate stability with these aircraft,” Mackey says. The aircraft’s sophisticated suite of surveillance and communications sensors will be represented in the flight tests initially by dummy weights. “We are in the lab doing integration work right now,” Mackey says, adding that air vehicle integration will be completed over the next “several months.” Sensors, particularly the multifunction active sensor active electronically steered array (MFAS AESA) X-band radar, continue to be shaken down on Northrop’s Gulfstream II surrogate BAMS flying testbed.

The MFAS, the heart of the aircraft’s patrol capability, is designed for maritime detection, tracking and identification of targets using maritime search, inverse synthetic aperture radar (ISAR) and SAR modes. Hoke says that MFAS is being tested first on a surrogate aircraft “to reduce technical risk and mature radar performance before integration on the Triton air vehicle.” Integration of a sophisticated radar on the Air Force Global Hawk Block 40 has drive that program behind schedule.

To assist with target identification, the MQ-4C will also carry the Automatic Identification System, which provides information received from VHF broadcasts on maritime vessel movements around the world. It will also incorporate an AN/ZLQ-1 electronic support measures system, and an ITT Exelis-developed “due regard” nose-mounted radar forward of the large wideband satcom antenna for safe separation from other aircraft.