A potential air safety incident on Tuesday involving the presidential helicopter—while President Donald Trump was onboard— in Washington, D.C., is being reviewed over a reported departure from standard practice put in place after last year’s deadly accident involving an Army helicopter and a regional jet over the Potomac.

According to the Wall Street Journal , which first reported the story, the Marine One helicopter took off from the Ellipse near the White House on Thursday, but commercial flights from Ronald Reagan Washington National Airport had not been halted as required by protocol.

This issue may have resulted in a “loss of standard separation” incident, which requires aircraft to be apart from each other by at least 1.5 miles horizontally and 500 feet vertically, the Journal report added, citing Federal Aviation Administration officials.

In a statement shared with Reuters , the FAA confirmed it is investigating a safety incident involving Marine One but noted: “It didn’t appear to be a dangerous close call.”

The Reuters report notes that the plane and Marine One were not “converging”; they did not maintain the required separation.

Roughly a minute after Marine One took off on Tuesday afternoon, a regional jet operated by American Airlines subsidiary Envoy ​Air headed to Pensacola, Florida, took off from Reagan Airport.

Marine One safely landed at Joint Base Andrews, from where the president flew to California for a Republican fundraiser event.

The safety incident involving the presidential helicopter over Washington D.C. comes about a year and a half after an Army Black Hawk helicopter collided with a regional jet operated by American Airlines near the Reagan Airport, resulting in the deaths of 67 people. The crash was the deadliest U.S. air disaster since November 2001. The incident followed several near misses and safety incidents near the Reagan Airport in the preceding years. As a result of the crash and findings from subsequent investigations, the FAA has enacted restrictions on helicopter flight in certain areas around the D.C. Airport. The Reuters reports also noted that air traffic control is usually given three minutes’ advance notice before Marine One takes off from near the White House to ensure a halt in traffic around the airport.

Last month, the Boeing VIP jet controversially gifted by Qatar made its debut as the new Air Force One. Trump flew on board the plane to attend a NATO summit in Ankara. However, amid a resumption of hostilities between the U.S. and Iran, Trump was forced to fly out of Turkey into RAF Mildenhall, a U.S. Air Force base in Suffolk, England, on board the old Air Force One plane. The president insisted that this was done to allow U.S. service members stationed at the base “a chance to tour the Aircraft,” however, reports suggested that the swap was made following a request from the Secret Service. This raised concerns about the new plane's safety features and missile defense capabilities compared to the older presidential jets. Despite his initial denials, Trump told reporters last month that the Qatar-gifted plane will undergo another set of upgrades and to get its security capabilities “maxed out.” The president didn’t specify what these new “maxed out” upgrades will cover, and it's unclear whether the one-month period is adequate to bring the new presidential plane’s security systems up to par with the older jets.

FAA Investigates Marine One Safety Incident in Washington (Wall Street Journal)

FAA says it is investigating Trump helicopter safety incident in Washington (Reuters)

Trump Says Qatar-Gifted Air Force One Will Undergo Another Upgrade For ‘Maxed Out’ Security (Forbes)