The military helicopter that collided with a regional jet near Ronald Reagan Washington National Airport in a crash that killed all 67 people aboard both aircraft was a UH-60 Black Hawk, considered the “workhorse” of Army aviation.

The helicopter is a “utility tactical transport” aircraft — used for everything from air assault to relief operations — that the Army says it has relied on for every major operation around the world for more than four decades.

First introduced in the Army in 1979, the aircraft is generally considered safe and has a strong track record for reliability and survivability in combat and transport missions, said Timothy A. Loranger, an aviation attorney and former aircraft mechanic.

Sikorsky, a subsidiary of the aerospace and defense giant Lockheed-Martin, says it has built more than 5,000 of the helicopters for 36 countries.

The Army has said it expects the aircraft to be a key part of its fleet for the next three decades.

The Black Hawk that collided with American Eagle Flight 5342 was from Bravo Company, 12th Aviation Battalion, out of Davison Army Airfield in Fort Belvoir, Virginia, and it was on a training mission, the Army said.

Military officials described the three soldiers on the aircraft as a very experienced crew that included an instructor pilot with more than 1,000 flight hours.

The officials said the training mission was a routine annual evaluation of the pilot’s ability to fly at night. The crew was well aware of the route and the rules in the airspace around the airport, the officials said.

The cause of the collision remains unclear and is being investigated by the National Transportation Safety Board.

Speaking to MSNBC, retired Army Lt. Col. Darin Gaub said video of the collision appeared to show that the helicopter did not appear to change course, speed or altitude before the crash, indicating the crew may not have known the passenger jet was in its path.

He added that the training mission had fewer crew chiefs than normal to scan the sky for potential dangers. While such missions typically have three, he said, Wednesday’s had one.

“That’s a fact,” he said. “It may have bearing in the future. It may not. But it does reduce ability of crew to identify an aircraft in flight at night.”

Nearly two years ago, two Black Hawk helicopters from Fort Campbell, Kentucky, collided during a training exercise, killing all nine soldiers aboard them.

That crash and a second fatal collision that involved two Apache helicopters in Alaska prompted the Army to ground all aviation except flights on critical missions.

Army Chief of Staff James McConville said the stand-down was necessary to ensure the Army was doing everything possible to prevent accidents.

A review of fatal incidents involving Black Hawk helicopters published by Military.com after the collision in Kentucky found 60 people had died in training incidents over the previous decade.

The review concluded that while that number may appear high, Black Hawks account for the fewest deadly incidents relative to hours flown in the Army’s fleet and are involved in far fewer fatal incidents than other helicopters, including the AH-64 Apache and the CH-47 Chinook.