Following several flight cancellations from Southwest Airlines, the Federal Aviation Administration will issue an emergency directive Tuesday.

Some small subsurface cracks have been found in some Southwest planes, Boeing 737 models. A similar crack is suspected to have caused a hole in a jetliner that forced an emergency landing in Arizona on Friday. There were no injuries reported in the incident.

The FAA will require specific Boeing 737 models to undergo initial and repetitive electromagnetic inspections for fatigue damage. About 175 planes must be inspected worldwide. About 80 of those are U.S. registered planes.

Officials will inspect aircraft in the -300, -400 and- 500 series that have accumulated more than 30,000 flight cycles. A take-off and landing is considered one cycle.