An autonomous US drone jet has completed its first unaided landing on an aircraft carrier in a milestone that paves the way to base offensive robot aircraft aboard strike fleets.

The Northrop Grumman X-47B flew on Wednesday from Patuxent River Naval Air Station in Virginia to the deck of the USS George HW Bush in the Atlantic without human intervention.

Unlike current drone aircraft in the US military arsenal, the prototype X-47B landed by using a predefined programme, and without live input from a human pilot.

Landing on an aircraft carrier is considered one of the most difficult manoeuvres for human pilots.

"It's not often that you get a chance to see the future, but that's what we got to do today," said Navy Secretary Ray Mabus.



The X-47B aircraft has a 3,200km range and the ability to carry the equivalent of two guided bombs, the stealthy X-47B raises the prospect an autonomous, long-range, radar-evading, unmanned strike aircraft.

It will be superseded by a new robot jet capable of reconnaissance and strike missions to be deployed aboard carriers within six years. Navy commanders insist that it will only fire its weapons on the command of a human.

Drone tactics

A carrier-based drone with those capabilities could be used to counter countries such as China and Iran, which have been developing missiles and other weapons aimed at forcing the US navy to operate far from shore in a conflict.

President Barack Obama has been criticised for the US's widespread use of drones to carry out extrajudicial attacks on foreign soil on those believed to be an "imminent threat" to US interests.

These include US citizens as well as foreigners considered "enemy combatants".

The US has justified drone strikes Pakistan, Yemen and Afghanistan as necessary to prevent terrorism. But many of those killed have been civilians.

Some experts say it is not clear that the navy needs a carrier-based drone.

They note that such an aircraft's main strength is the ability to remain over a target area for long periods of time looking for potential threats like mobile missile launchers.

Land-based drones can provide that capability as effectively as sea-based ones, they say.

"When it comes to operating an unmanned aircraft from carrier decks, the navy seems to be ambivalent about the whole

idea," said Loren Thompson, a defence expert at the Lexington Institute thinktank.

He said the navy needs to conduct a rigorous assessment to see what the drones would bring to the fleet that cannot be accomplished with manned aircraft or land-based drones.

"Can we fly drones off of aircraft carriers? Yes we can. Is there a good reason for doing so? That's not as clear," Thompson said.