May 27, 2011

Time Out - NextGen Ramblings

Apparently, we skipped spring and jumped right into summer. Every single shift this past week was a doozy, and I've resorted to a triage of sorts to decide if any of it is blog-worthy. So far, I've been distracted by the latest article at the Praxis Foundation (link on the right).

I'd like to talk to you about "data-link communications."

Some older controllers in my area dismiss the whole thing; Data-link has been "imminent" for 15 years. That may be the case. As a member of the newer generation of controllers, I'm not afraid of change for changes sake. But, even I can't see this integral part of NextGen getting off the ground. Here is why:

1 - What is the last thing you want your bus driver/airline pilot/train engineer doing when you're sitting in the back with your life in their hands? Texting on the cell phone, right? Data-link is texting while driving. A message is received, and one or both pilots have to put their head down and read the message, and then presumably, they have to text someone back that they received the message. Currently, pilots respond on the radio by holding down a button, either on the control stick or nearby in an easy to reach spot (see picture below, arrow points to a little red button - push to talk). Left hand on the yoke, with one finger dedicated to talking on the radio, the right hand is on the throttle. Where in this cockpit would you put the screen to get ATC clearances? I say we keep the clearances in the headset so the eyes can stay focused out the window looking out for things like other airplanes, weather, mountains and/or the runway.

2 - As pilots fly around, they often ask controllers if there is any turbulence ahead. Sometimes this comes off as annoying, but at least when we answer the first call "light to moderate turbulence from FL310 to FL360, everything gets smooth west of SYR", others around hear it, and can simply request FL380 without further conversation. Granted, pilots sometimes stop listening after someone else's call sign is used.....

There are many benefits to having everyone on one frequency together. Pilots hear turbulence reports, as I've mentioned, but they also get a sense of how busy the controller is to a certain extent. They hear about weather deviations, they hear holding instructions and other delays. From personal experience, "verify you are declaring an emergency?" is the quickest way to shut everyone up.

If everyone just got the messages meant for them, they would have NO IDEA what is going on around them. Situational Awareness would be significantly sacrificed. This is a clear case of safety taking a back seat to supposed gained efficiency. This issue would be much more magnified in the Terminal environment around and on the airport.

Obviously, this is a much more significant issue for single pilot operations, of which airline flying generally isn't subject, but I would assume pilots try to spend as little time as possible with their head down entering data into their flight management computers (or being distracted by burnt out landing gear light bulbs....). Lets not encourage them to take a 40 year step back in safety.

Till next time...



Anonymous said...

At some point, you'll reach saturation where no tools will help you manage traffic. Wouldn't it be nice if the systems could help automate the repetitive, mundane tasks so you could focus on the exceptions? What happens when there are strategic tools introduced that help change routes four hours from your sector? Do you want to be reading lat/long's in the mic?

I am with you on the it will never happen though. Too much politics, too much cost for not enough benefit. But I can tell you it revolutionized the oceanic side.

Praxis said...

May I follow up a bit? First, they're struggling to find NextGen justifications, so they've added the "datalink" benefit - even though voice comm hasn't been identified as a problem. So it's a bit of hype, a partial solution to a non-existing problem.

One interesting point is the FAA won't own the datalink infrastructure - taxpayers will pay ARINC $.05 for each transmission just like with PDC and DATIS. We will be completely relying on ARINC.

Second, datalink works - it's been used in the military, etc. But all the tests in Atlantic City confirm that datalink has a time latency (delay) of 3 to 5 seconds.

So datalink is absolutely useful for routine transmissions that are not time sensitive - landing info, a routine descent from abeam, etc. Datalink is not usable for ATC when timing is essential - turns to final, etc.

Datalink will NOT replace voice, it will supplement voice, and probably reduce voice comms. (And at times, the voice channel is the limiting factor in sector capacity).

What datalink might do is overload your sector to the point at which you can't talk to everybody. Think about that for a while.

Finally, to take the well-rounded view we should point out that FAA told the airlines years ago that if they'd invest in Mode-S transponders, we'd exchange datalink info.

Airlines spent the money, FAA never implemented the change.

The impact of Mode-S datalink non-implementation is demonstrated in the TCAS RA manuever in the terminal environment, when the pilot says "we're executing an RA" and the controllers have to wonder what they're doing - the planes are transmitting their manuever on Mode S, it's just that the FAA system isn't listening.

And these are the people who are going to deliver datalink?

Datalink has benefits, it's great for non-time-sensitive communication, but it's not going to replace voice. It's disingenuous to say that it's a justification for NextGen, which is not retro-compatible and is going to cost many billion$.

By the way, excellent blogging, keep it up.

Anonymous said...

One of the best anti-modern BS rants I've so far read.

There're reasons why many things worked better in the past...Various aviation aspects being one of them.


Don Brown said...

-- NIce post. Great analogy. Keep it up.

Don Brown

Landis said...

The little red button in the picture is the autopilot disconnect - but the PTT is just behind it. :)

As for data link, I agree with some of the other commenters. I've heard "blocked" quite a bit while flying. I definitely agree that situational awareness is greatly enhanced by having all of us on the same frequency but things like clearances and amendments to routings could be easier all around and more accurate when presented via text.

There's a time and place for both methods of communication.

Anonymous said...

Agree with comment that each method has its use.

When TDLS was proposed, controllers thought it would be terrible. Now they can't live without it.

Controllers use data continuously have have the same "eyes on the screen" issue. I doubt they would be willing to give up their data sourcesl.