SAN FRANCISCO (KGO) -- The investigation is in full swing along the Potomac River next to Ronald Reagan Washington National Airport in Washington, D.C.
As to what may have gone wrong and caused an American Airlines commercial jet and a Black Hawk helicopter to collide, as seen in Earthcam video above, we spoke with former NTSB investigator Greg Feith and former Black Hawk helicopter pilot Elizabeth McCormick.
"The one concern I really have is why the Black Hawk crew was not at 200 feet or lower," Feith said.
"They should not have been that high, that's my opinion, unless there was a mechanical issue that would be pilot error," McCormick said.
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"The question is why was this particular crew, the Black Hawk crew above that 200 feet. They were actually closer to 400 feet, which put them right at the same altitude of the regional jet," Feith said.
Sixty-four people were on board the American Airlines plane, which had departed from Wichita, Kansas. Three soldiers were on the helicopter.
There are also questions as to what regional jet, or RJ, the Black Hawk pilot saw before the collision.
"When the controller issued, 'Hey do you see that RJ?' And he asked the military crew twice, 'Do you see the RJ?' They didn't respond in the affirmative of 'I see the RJ.' They said we have the aircraft," Feith said.
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"If you look at that first video that came out in the foreground, you see a plane taking off, a small commuter jet taking off, and the helicopter was heading towards that small commuter jet. I'm confident that when they say 'Yup, I've got it,' they were looking at this one not knowing there was one coming behind them," McCormick said.
McCormick says that having three people in that helicopter instead of four could have also limited their ability to see behind them.
Both Feith and McCormick say that investigators will try to determine if night vision goggles were still being worn, which could have created more of a problem in the brighter area near the airport.
"It's possible and most likely that they had absolutely no idea that they were about to be in a collision," McCormick said.