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A Day in the Life of the X-47

x-47 on the cat.bmp

Northrop Grumman builder of the X-47B Navy unmanned combat air system demonstrator delivered an interesting brief in Washington, D.C., last week on what a typical mission would look like for one of its flying-wing design robot airplanes.

Company officials working on the project are realistic about naval aviators' enthusiasm when they consider sharing their carrier decks with an unmanned drone. Thats why the Navys putting money toward the UCAS-D program. They want to make sure the system can integrate seamlessly into the current naval flight environment with no major changes to naval operations with manned aircraft.

No one doubts this is a tall order. But over the years many of the most difficult aspects of carrier aviation have been tested with unmanned systems, including carrier landings and take-offs and integrating drones into the pattern for approaches and traps. In fact, Northrop Grumman engineers tested a business jet equipped with a drone brain out of Patuxent River Naval Air Station in December where they simulated a carrier approach and integrated into a virtual pattern of other landing aircraft.

Here is how an X-47B mission would go:

A deck handler (also known as a "yellow shirt" in carrier parlance) will use a wrist-mounted display and a hand-held joy stick to maneuver the drone from the hangar bay elevator into position on the flight deck. The planes jet engine, of course, powers it on the deck, but the deck handlers controller adjusts throttle position and braking.

When it's time to gas up, fuel will be pumped into the drone through an inlet hidden within the landing gear housing and up to six small diameter bombs can be loaded into each recessed bomb bay using the same winching system featured on the F-35 Lightening II.

The yellow shirt's job is over once the drone is maneuvered into the catapult shuttle. Hook up to the catapult and shuttle is the same as any other aircraft. All hand signals stay the same as well.

One of the goals we had is we couldnt change any of the procedures on the flight deck. Our plane had to look like every other plane on the flight deck and act the same way, said Northrop Grumman UCAV program official, retired Rear Adm. Tim Beard.

The catapult shot is like that of any other manned aircraft. Company officials noted that F/A-18s fire off the ship autonomously anyway (pilots keep there hands off the stick during cat shots), so the initial launch isnt a huge technological or cultural stretch. Once airborne the drone will fly a pre-loaded profile, but the profile can be updated as the mission progresses.

The X-47B will complete its mission and be directed by its operator to take its place in the stack of returning manned and unmanned aircraft approaching the carrier. This is perhaps the most difficult part of the developmental test regimen for engineers and Navy officials. But Northrop Grumman program managers are confident there wont be any huge surprises.

At about 200 nautical miles from the ship, the drone communicates its position and is relayed automatic routing information by the control station aboard the carrier. Similar data can be transmitted to the manned aircraft so each plane can take its place in the landing order.

In effect, each pilot is getting signals of airspeed, heading and altitude to bring him or her [or it] down to the ship, Beard explained. Theoretically, with all-digital cockpits and the architecture weve got in the airplanes, everyone can couple up and be fully automated from 50 nautical miles in.

At three quarters of a mile, the LSO near the fantail and the Air Boss in the tower have to decide whether the drone will be allowed to come aboard - just as they make that decision with manned jets. The LSO will have a switch at his station that will send a signal to the flight control computer below decks, then out to the UAV that says to the plane youre allowed to come aboard.

At the same time, if the Air Boss sees something go wrong on the flight deck hes got a button that he can hit and the airplane will take a wave off, Beard said. The LSO has a similar switch as well.

Its exactly the same thing we do with manned airplanes at sea, Beard said.

At about 50 feet from the ship, a precision GPS system that triangulates data down to a couple of inches from the landing wire figures position data between a GPS receiver on the drone, one on the ship and the inertial navigation system.

The UCAS-D will be tested to Case I, III and III landing standards. But even in the worst weather imaginable, the X-47B drone wont give humans heartburn, Beard said.

As soon as the wheels of the drone hit the deck, the plane powers up for a touch-and-go in case of a miss, just like manned aircraft. At a programmed deceleration of the trap wire, the drone initiates trap logic that pulls the power to idle, returns control of the aircraft from the mission operator below to the yellow shirt who uses his controller to taxi the robot plane to a parked position.

No matter how smooth the process looks on paper, and no matter how many times this scenario has been tested on computer simulators or other aircraft, Northrop Grumman officials acknowledge they have a big job ahead of them and a lot of minds to change in the process.

Were talking about a real leap in confidence, Beard admitted. But its a process of education.

-- Christian

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