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[quote=Anonymous][quote=Anonymous][quote=Anonymous]The CRJ was banking to the left so the helicopter was seeing the bottom of the plane where there are far fewer lights.

I think this is just a case of human error. They were looking at another plane, didn't see this one as it was coming from a different direction and flew into it. Human error is always a possible risk and that is why air spaces need to be as safe as possible and have as many contingencies as possible to account for human error and prevent tragedy. Which is usually what happens and is what happened the day before.

The investigation won't necessarily be about assigning blame but what changes need to happen to prevent this happening again. [/quote]

I agree with the bolded and generally with the the idea that this is likely a case of human error for which we need to better insulate the system.

However I disagree that we can know what the helicopter pilot saw or why they did what they did at this point. I know many people, including many fellow pilots, are eager to say that this was an understandable mistake based on visibility in that corridor at this time of night. I think it is important those perspectives are heard and accounted for -- that may indeed have been what happened.

But we don't KNOW that's what happened. There are other factors here, including the helicopter's last minute maneuvers that brought it directly into collision with the airplane (veering SW and rising over 100 ft in altitude in a short period of time). To be clear, I do NOT think this is evidence that it was intentional. I just think it's weird and it's not explained by the speculation that the helicopter could not see the plane. If this were just a question of the helicopter not seeing the plane, presumably they would have maintained their current trajectory, right? The only direction they received from ATC was to go behind the plan, which even if they thought it was further away, "behind" a plane approaching either runway at National would mean moving to the east, not to the west.

There are too many unanswered questions for us to conclude what happened based on the commentary of other helicopter pilots who have flown that route. Their input is very helpful but not a full answer.[/quote]

So I have a couple of thoughts on the last minute maneuvering of the helicopter. This is all pure conjecture, not stated as fact of events, more to illustrate just how much we can't possibly know at this stage.

First is to question whether there really was a bank to the right at the last second. As far as I know, that is based on the radar track from publicly available tracking sites. I can tell you for certain those tracks are not precise. They are based on intermittent pings, not continuous, and each ping has an error tolerance around it. If one ping is biased one way, and the next is off a bit the other way, it can easily look like a change in direction when the vehicle is actually traveling in a straight line. And the timing between pings can make a smooth arc look like a sharp jerk.  Same issue with altitude.  They only report 100s of feet, so a "climb" from 200 to 300 might actually mean they wavered a little from 230 to 260 ft.  The videos mostly seem to show the helicopter in level flight, so I'm not actually sure what is right.

More precise data, which the NTSB will have access to, should answer that question.

Second is one plausible explanation if there was an actual jerk to the right. Let's say (remember, conjecture here, not statement of fact) they were initially fixated on the wrong airplane, or even a tower light somewhere in the distance that they thought was the plane. Then, at the last second, one of the pilots saw the actual plane closing in from the left. I don't care if you were told to go behind it - if you realize a collision is imminent, it's human nature to yank the controls away from the object you think you'll hit. Unfortunately, that only works for avoiding a static object, not a moving one.  In this case, yanking the controls away from a plane that (from their perspective) suddenly appeared at their left could have meant a sharp bank to the right, which actually could have put them in the path of the very plane they were trying to avoid.  Human instincts don't work well in 3D - ask anyone who has learned formation flight how much training it takes - and in a split-secomd panic situation people often revert to instinct.  If that is the scenario (or anything like it), I'm not saying it absolves the crew of responsibility; just giving a possible explanation that doesn't involve suicide or mass murder.  Unfortunately, unless the pilot verbalized this and it was caught on a recorder, we'll probably never know WHY they started the bank (if they actually did).[/quote]

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