An aviation geek's take on the mid-air collision

Please view the following link to see a screenshot of Donald's ATC screen.
http://i102.photobucket.com/albums/m93/Bschott007/BB/vlcsnap-2002993.png

Now my take on the mid-air collision is this: KUDOS TO VINCE! Listening to ATC (shout out to the guys over at http://www.liveatc.net !) and having a strong interest in aviation made this scene a little contrived, but still powerful and hey...they got some of the details right...not all but most.

Vince got the ATC dialog correct. In case it's not known ABQ is Albuquerque. Donald was ABQ approach and was handling the planes in the controlled airspace around the airport. The way I know this is his dialog handling other aircraft. My nitpick here is that they showed him using a scope mode which enroute controllers use, approach/departure controllers use a different scope setting. Not a big deal, it got the point across that it was an ATC scope.

Depicting the two aircraft colliding almost directly over Walt's home, I thought that was stretching thing just a little bit. Yeah, Walt's home was on the approach path of the airport but that just seems so heavy handed to have them collide almost right over top of Walt.

Before I go into a few nitpicks on the collision from me, an aviation fanatic, I want to say that I love the show and while I can point out where they went wrong in the writing, I can still enjoy the scene for how the writers meant us to view it. I can give them the "Suspension of Disbelief" to enjoy their writing...but I still can point out what was wrong in the script :)

NITPICK 1: It had been seven seven weeks after Jane's death when Donald came back to work. In the real world Donald would have been forced to go through grief consoling and see a mental health doctor before being allowed anywhere NEAR the ATC building. He would have had to been cleared mentally before being allowed to return to work.

NITPICK 2: A 737 (or any aircraft with 30 or more seats, flown in US airspace) is required to have a "TCAS II" (Traffic Alert and Collision Avoidance System). TCAS were specifically invented to avoid mid-airs from occuring. For those who are not aviation geeks, the TCAS is a device that would have let the 737 PIC (pilot in command) know about the impending collision as soon as or even before ATC would have known about it. The TCAS would have first issued an audio and visual warning in the cockpit (a 'Traffic Advisory' (TA)) to assist pilots in visual acquisition of the small, general aviation aircraft that hit them in the show. The pilots in the 737 would have known there was traffic at their 3 o'clock and would have been looking to see it.

Their TCAS also would have analyzed the projected flight path of approaching GA aircraft and issued a 'Resolution Advisory' (RA) to the pilot to resolve the potential mid-air collision. Basically if you were an airline pilot inside the US an a TCAS tells you that there is a collision about to happen, then gives you an RA, you disregard whatever the ATC is saying and follow what the TCAS tells you. The control can only say "Roger" per the new updated (2007) FAA rules if the PIC states "TCAS CLIMB" "TCAS DESCEND" or "TCAS ADJUST SPEED". Now this nitpick can be written off by the writers as TCAS isn't 100% effective all the time and could be stated as not working or had not given warning to the pilots. I'll give them some slack on this boo-boo.

I just watched my DVRed copy of the episode and found Donald was acting appropriately for the situation. I can only speculate that he didn't recognize there was a possible collision in the making early enough.

I have frozen the screen and even played back the scenes of the ATC scope but he did everything he was supposed to do up to avoid the collision. This is a BIG KUDOS from me to Vince for getting this right on the button. My nitpick is that the scope had things goofed up when it came to the action that took place...more on that later.

Now, Donald gave the traffic advisories as both aircraft were under his control. He was required to give at least one of them a vector or altitude change to avoid the collision, which he did as follows:

"Juliet Mike 21, turn left heading 115."
"WAF Air 515, traffic 3 o'clock, turn left heading 085."

Which if you look at the screen was not correct. Juliet Mike was traveling on a heading of 72 or 73 degrees and headed east per the motion of shown on the screen. Juliet Mike would have had to turn RIGHT to heading 115, not left. The command to WAF Air was correct though. He needed to turn left to get to 085. Probably just a script boo-boo.

A small nitpick is the scope shows the aircraft in collision with their heading tails pointed away from their direction of travel...this is not correct, but if you stop the scene you can see all the other aircraft have the correct heading flag pointing in their direction of travel with the correct 'hashing' to indicate speed and previous positioning. So basically it looked like the aircraft were flying backwards on the scope. I got a chuckle from that but still can respect what the writers were trying to do.

Notice, however, that neither aircraft seems to obey his orders and continue on their original courses without regard to the controller.

He then says (as the ringing begins and his voice is drowned out. This is NOT a warning bell as some have suggested. It is the same 'mental blanking' device the writers used in the Pilot episode to depect when Walt was zoning out the world.)

"WAF Air 515, descend to One Zero thousand" (Uh...why? He is cruising at 24,000 feet per his data block.)
"Juliet Mike 21, do you have the traffic at your nine o'clock?"
"WAF Air 515, do you have that traffic?"

The aircraft could not have collided given their data blocks on the screen. The 737 was cruising at it's assigned altitude of 24,000, speed of 405knots, (squawking IDENT of 203).

The King Air was descending from 16,400 to 10,000., speed of 443 knots (squawking IDENT of 209).

They were showing aircraft with nearly 8,000 feet of vertical separation between them. No chance of a collision. Oh, you will also notice that during the radar updates on his screen, the data blocks never change. If you are not an aviation geek you probably wouldn't have caught this and really, it doesn't take away from the overall feel of the scene.

The fact is neither pilot had made their turns. WAF Air stayed on his/her heading of 91 to 93 while Juliet Mike 21 was on a heading of 72-73.

Ok, let's say that the ATC screen was correct and the planes were in a collision heading. Considering you have a very large cow in the sky (the 737) and a fairly small and quick dog, (The general aviation King Air) he should have seen the 737 was not obeying and would be the harder aircraft to turn if it did obey, so he should have called out something like

"King Air: Turn IMMEDIATE to zero eight zero for traffic. EXPEDITE!"

When a controller says Immediate, you sit up, pay attention and put your life in his hands. He has a bigger picture than you do of what is going on in the air. It means whatever he said, do it and do it promptly

When a controller needs to say EXPEDITE, they mean RIGHT THE **** NOW!

Put them together and it means "Do what I say, do it now, do it without thinking, or you WILL end up dead in the next few seconds"

Neither plane was listening to him per what we were shown on the scope. Based on this, Donald was in the clear, unless he wasn't holding his transmit button or his mic was faulty.

One could say that Donald should have seen this become a problem long before the aircraft were even close to each other...and most controllers with what looks to be Donald's experience level...would have been able to mentally visualize where these planes were going and have seen this problem long before it occurred.

Anyone interested in ATC should check out the movie Pushing Tin. The movie itself is a dud, but how they portray the way an ATC controller thinks, communicates with pilots and other controllers and how ATC scopes look is right on the money. Too bad the rest of the movie is crap.