A man working on a Boeing 747 at an airstrip near Marana was critically hurt when the landing gear collapsed and he was trapped under the plane, authorities said.

The worker was part of a crew disassembling the retired passenger jet at Pinal Airpark Wednesday, Pinal County Sheriff's spokesman Mike Minter said.

For unknown reasons, the landing gear suddenly retracted and the plane fell, trapping Stanley Nye in the gear compartment, Minter said.

He was eventually freed and taken to a Tucson hospital, where he was in critical condition.