The Federal Aviation Administration says it has found no safety problems at Southwest Airlines after launching several months-long investigations in July following several close-call incidents.

The most notable incident occurred in April, when a Southwest plane came within 400 feet of crashing into the sea off the coast of Hawaii.

But several other incidents have been investigated, including a flight to Phoenix, Arizona, that in May experienced a “Dutch roll,” a southwest flight from Ohio to Florida that came within 150 feet of the water before making a go-around was conducting and flying in June when a Southwest plane crashed at 525 feet over Oklahoma.

Southwest said in a statement to ABC about the agency’s completion of the review that it “appreciates the opportunity to work with the FAA as part of our shared commitment to safety.” Nothing is more important to Southwest than the safety of our customers and employees.”

The FAA also issued a statement following the investigation saying it had “completed its Southwest Airlines Certificate Holder Evaluation Program (CHEP). The review found no significant safety issues.”