The Federal Aviation Administration has issued a “safety call to action” and will form a safety review team after a string of concerning airline incidents.

“We are experiencing the safest period in aviation history, but we cannot take this for granted,” FAA Acting Administrator Billy Nolen said in a memo released Tuesday. “Recent events remind us that we must not become complacent.”

The memo was an acknowledgement of recent close calls plaguing the aviation industry.

In January, a Delta Air Lines plane about to take off was frantically ordered to halt when controllers noticed an American Airlines aircraft crossing its path at New York’s John F. Kennedy International Airport. In December, a flight taking off from Maui plummeted to merely 800 feet above the Pacific Ocean before recovering. And earlier this month, in Austin, a FedEx cargo airplane trying to land and a Southwest Airlines flight preparing to take off narrowly avoided a potential collision.

Nolen said he is forming a safety review team “to examine the U.S. aerospace system’s structure, culture, processes, systems and integration of safety efforts” and look for opportunities to address safety risks.

A Safety Summit will be held in March to explore what additional actions should be taken to ensure aviation safety, the memo said.

“A group of commercial and general aviation leaders, labor partners, and others will examine which mitigations are working and why others appear to be not as effective as they once were,” Nolen said.

The FAA chief also said he is asking the Commercial Aviation Safety Team to “take a fresh look” at Aviation Safety Information Analysis and Sharing data to see “whether there are other incidents that resemble ones we have seen in recent weeks.”

“We need to see if there are indicators of emerging trends so we can focus on resources to address now,” he said.