A ground stop was issued Wednesday evening August 6, 2025 affecting about 40 percent of United Airlines flights across the U.S., according to the FAA.
“Due to a technology issue, we are holding United mainline flights at their departure airports,” according to a United Airlines statement. “We expect additional flight delays this evening as we work through this issue. Safety is our top priority, and we’ll work with our customers to get them to their destinations.”
The technical issue apparently involves the weight and balance system, which is part of a system known as Unimatic, which also provides other aircraft system information. In air travel, weight and balance refers to the process of calculating and managing the distribution of an aircraft’s total weight to ensure the aircraft operates within safe limits. The factors include consideration of the weight of the aircraft itself, along with all occupants, cargo, and fuel, and ensuring the center of gravity (CG) remains within the approved range. Improper weight and balance can lead to performance issues, handling difficulties, and even safety hazards.
The affected airports included Chicago, Denver, Houston, Newark, and San Francisco. Over 1,000 flight were affected.
The problem was resolved Wednesday night, but there were residual issues Thursday, August 7, 2025.
