They are the biggest birds in the sky over west San Antonio.

Giant Air Force C-5M Super Galaxy cargo aircraft are constantly flying around JBSA-Lackland, but not now. The entire fleet is grounded while maintenance workers replace a part of the nose landing gear that engineers believe might be subject to failure.

The air mobility commander of the Air Force, General Carlton D Everhart II, ordered the stand down until repair work is completed.

The Commander of the 433rd Airlift Wing, Colonel TK Smith, said that the 400,000-pound aircraft is temporarily grounded to change out a 100-pound part.

Climbing into the nose gear wheel well, Smith pointed out the giant assembly, noting “It's engineered big, just like Texas.”

“The problem is if the ball screw assemblies were to fail and the landing gear would not retract or extend when commanded, obviously not a good thing if you're going to go flying,” Commander Smith said.

These large machines are the biggest airplanes in the Air Force inventory and they are a source of pride on the west side, as much a part of the landscape as nearby Wolff Stadium, home of the San Antonio Missions.

"Even though we are a reserve wing, we are flying seven days a week, 24 hours a day," Commander Smith noted. "We're the 433rd Airlift Wing, but we proudly claim to be the Alamo Wing."

Commander Smith added that replacement parts will be delivered soon, and they will fix all eight local aircraft as soon as they can turn the wrenches because this mission is important to America.

"It's the quickest way to get things where they're needed," he said.

And they're a point of hometown pride.