Harrison Ford 'Completely Misjudged Runway' ... Last Second Save on Taxiway

This is a photo of Harrison Ford landing on the taxiway Monday at John Wayne Airport ... and the person who took the pic says the actor was totally out of position seconds before he touched down.

The man who shot the photo had just arrived on a commercial flight and was looking out the terminal window waiting for a friend, when he saw Ford's plane coming in for a landing. He tells TMZ Ford had "completely misjudged the runway" and was not in position to land.

The man grabbed his phone to snap a pic, thinking the pilot might crash, when Ford "banked really sharp." He says the plane was "very close to the ground" when it banked and "hit hard" on the taxiway seconds later.

You see the ramp agent in the photo ... he seemed "shocked," according to the guy who took the pic.

The eyewitness account differs from the story that's being told that Ford simply mistook the taxiway for the runway.