MARK MCEATHRON: I'm a Black Hawk helicopter crew chief. This video shows all the red flags that led up to the deadly DC plane crash

I'm a former Black Hawk helicopter crew chief and flight instructor.

I know how quickly a routine flight can turn into a terrible tragedy.

That's why it's been so disheartening to hear the misguided criticism being put forward as an investigation into Wednesday evening's deadly crash of an American Airlines commuter plane and a US Army helicopter over Washington DC just gets underway.

Online trolls are spinning the conspiracy that this tragedy was somehow intentional. But anyone telling you that this collision is suspect has never been in a flight crew in their lives.

Ignore them all. Better yet, mock the heck out of them.

I don't claim to know what caused this horrific accident, but in my experience there's always a combination of factors – a 'perfect storm' of mistakes – and human error is almost certainly counted among them.

In this incident, there are least three 'teams' to evaluate: the Army helicopter crew, the American Airline pilots and Ronald Reagan Washington National Airport's air traffic control.

First, there's the Black Hawk crew.

During my six years in the US Army, I trained helicopter crew chiefs. It is their responsibility to be the eyes of the pilot and co-pilot, who – ironically – spend much of their time with their attention trained inside the aircraft.

They must monitor multiple radio channels, and in cities like DC, the wireless traffic is constant. There are also instruments to check, fuel gauges to watch and checklists to evaluate. All of these factors are exacerbated when flying at low altitudes – as this reported training mission apparently was.

There, indeed, can be moments when all three crew members in the cockpit are not looking outside the aircraft.

That's not supposed to happen, of course. Pilot and crews are supposed to announce and coordinate when we are 'coming inside' or going 'back outside' the aircraft. But that doesn't always happen.

Plus, even with three-trained aviators in a cockpit, it's nearly impossible to navigate with the naked eye – especially at night.

This is important to keep in mind if you watch the video of this particular crash, which appears to show the Black Hawk flying directly in front of the well-lit passenger plane from a long distance.

All aviators face the challenge posed by optical illusions.

Most people have experienced similar sensations in their everyday lives.

If you're in a car driving down the road and you look out the window at trees, they seem to be moving very fast in relation to the car, while the hills in the distance appear to be moving very slowly. In reality, neither are moving at all. This is an illusion. Pilots can experience a related phenomenon that is even more extreme.

If conditions are right, flying objects can look as if they're stationary.

In navigation, the phrase 'constant bearing, decreasing range' (CBDR) refers to two aircraft that are travelling at certain angles, speeds and directions and in the absence of any visible reference points.

It is possible for two pilots to fly toward each other without either of them be aware of it.

At night and in a city, this illusion is magnified, because a pilot may not realize that a seemingly stationary light is actually an aircraft.

I'm sure that American Airlines commuter airline was lit up like a Christmas tree. But it may not have mattered to Black Hawk pilots. In a brightly lit city, like Washington DC.

As for the airline pilots, they may have been completely oblivious to that Blackhawk traveling through their flight path.

These military helicopters are designed to be hard to see at night. The red and green lights on the side get lost in the lights of the city below. The only 'lights' on top of the aircraft are called 'slime lights' because they are a very dim green.

Moreover, on approach to landing, the commercial pilots are not looking outside of their aircraft.

At that point in the flight, they're relying on their instruments, being guided by radar, checking their speed, altitude and which runway they've been directed to land on.

The AA pilots would have been relying on air traffic control to clear the airspace – obviously, that didn't happen.

Finally, the role of air traffic controllers will be a major focus of any investigation.

One of the things that I did not like hearing on the recordings of the air traffic control conversation in this accident is that the Reagan National Tower asked the Black Hawk pilots if they simply saw the other aircraft, just moments before the collision.

That's not a helpful instruction from the perspective of a pilot, because they wouldn't know where to look. Perhaps, the Black Hawk pilots did identify what they thought was the aircraft in question – but it was another plane taking off at the same time.

As a pilot, I would want to hear, for instance: Do you see the aircraft three miles away off your 11 o'clock and flying at a hundred feet?

I would want a direction, altitude and a distance. It appears that these Black Hawk pilots did not get that information.

You can also hear air traffic control giving the Black Hawk permission to 'go behind' the approaching aircraft, but if the Black Hawk didn't see that aircraft, they wouldn't know where to go.

There are still many unanswered questions. But I know this: 999 out of 1000 aircraft incidents are caused by a series of human errors.

Today, my heart and mind is with the families of those involved in this tragic event.