For months, the U.S. military has been flying the Osprey, despite questions about whether it should be.

The Tilt Rotor aircraft was grounded after a crash in Japan last November that killed all eight airmen on board.

That crash was the fourth by in Osprey in the last two years.

The military allowed the fleet to fly and said it mitigated the problem that caused these accidents.

But the families of those killed in the crashes aren't convinced the Osprey is safe and want it grounded again.

Nick Schifrin and producer Dan Seagallon report from North Carolina.

At Marine Corps Air Station New River, the Marines of the Fighting Griffins approach the aircraft

they called their workhorse.

The MV-22 Osprey had been grounded for three months before we visited this summer.

So Captain Dave Schroeder is eager to fly and make sure it's flight ready.

He's an instructor who trains junior pilots. Do you get rusty? Do

other pilots get rusty? Absolutely. Flying is a skill. He's been flying military aircraft for more than a

decade. He calls the Osprey one of a kind and gives it his full faith. I'm fully confident

in the way that this aircraft performs and I trust my life and it.

The flexibility provides and the speed of range that we can operate is really unmatched.

The Osprey takes off like a helicopter and flies like a plane at twice the speed of other helicopters.

The Marines call it essential to their mission, and on average deployed 20 ships every

day last year.

But it also has a history of high-profile crashes.

An experimental Marine Corps aircraft crashed today.

In Afghanistan, a U.S. Air Force Osprey went down.

A U.S. military Osprey aircraft crashed into the sea off Japan today.

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