United Airlines Holdings (NASDAQ:UAL) has been cleared of any significant safety issues by the U.S. Federal Aviation Administration following a 7 month long investigation by the regulator into several non-fatal incidents with its aircraft.

During the course of the investigation, United (NASDAQ:UAL) was unable to certify new planes to its fleet or add new routes.

The scrutiny into the carrier was triggered by a series of incidents involving its Boeing (BA) fleet that raised concerns about safety and maintenance procedures, including two separate incidents in which a tire fell off planes during departure, a hydraulic leak on a Boeing 777, cracked windshield on an aircraft headed to London, a 737 skidding off a runway in Oregon, and engine fire in Florida. In a separate incident, a passenger entered the cockpit of a chartered United (UAL) flight while traveling with a professional baseball team.

“The review did not identify any significant safety issues,” the report states, adding that the FAA has ended “enhanced oversight and approval process for United to add aircraft and services.”

United (UAL) shares are fractionally lower in premarket trading and expected to trade defensively for a fifth consecutive day.