Friday, March 14, 2008

Think Tank Thunk



Recalling (if you will) yesterday’s blog, Robert Poole of The Reason Foundation wrote to Mike Lewis of the Boeing Company’s ATM (that’s Air Traffic Management) business unit to dispel my “eloquent” but quaint notions about air traffic control. Mr. Poole, being true to his word, sent me Mr. Lewis’ full remarks (very quickly I might add) upon request.

Let me pause here to make my first point.

As I told my regular readers in a post (oddly) entitled “A note to my regular readers”:

”In reading Air Traffic Safety vs. Capacity, it won’t take you long to realize it’s a departure from my normal style on this blog. I wrote it with the intention of selling it and getting the information in front of a more general audience. In other words, you’ll notice that it was written for a non-aviation audience. It has some uncomfortable generalizations... “

Giving Mr. Lewis the benefit of the doubt, I’ll assume he is not a regular reader and didn’t see that note. I don’t assume that Mr. Poole is a regular reader either. I just thought it worth noting that Mr. Poole felt the need to turn to his “expert” to try and dispel the assertions in an article written for a general, “non-aviation” audience. Moving on...

Mr. Poole did an excellent job summarizing Mr. Lewis’ main points. They were:


• "GPS, centimeter-precise digital maps, synthetic and enhanced vision, taxi-map displays, and precision guidance can eliminate visibility as a constraint.

• "ADS-B, multilateration, integrated radar, and flight deck displays can precisely locate all traffic.

• "RNP routings, trajectory tracking and planning can give very accurate four-dimensional paths for use in automation and displays.

• "Wake vortex detection and tracking could show where wake hazards are—and aren't. (This is the one area that still needs advances in technology.)

• "With these items in place, we could safely operate with more than one plane on a 10,000-foot runway, especially with departures."


Let’s take them one at a time.

”GPS, centimeter-precise digital maps, synthetic and enhanced vision, taxi-map displays, and precision guidance can eliminate visibility as a constraint.


I addressed this issue in The Silver Lining . “ The trick would be to improve IFR operations to nearly the level of VFR operations. It could be something as high tech as synthetic vision to something as low tech as the angled flight deck on an aircraft carrier.” It’s interesting that Mr. Lewis chose to mention “taxi-map displays.” I’ve been asking around about this same question. (I’m not an expert on cockpit displays either.) It turns out that most airliners don’t have them, but according to my sources, they’re now coming on line. We could argue about the “why”s but it misses the larger point that they don’t. Regardless, we still bump into the theoretical limits of VFR runway capacity even if we manage to conquer the IFR limits by requiring half-million dollar (or more) upgrades on every commercial aircraft. Synthetic vision is not cheap.

”ADS-B, multilateration, integrated radar, and flight deck displays can precisely locate all traffic. “

To which I answer; “So what ?” I will point out that Mr. Lewis has the good sense to include ADS-B and radar. The FAA would have you believe ADS-B is going to replace radar. It isn’t. I’ll be honest, I really don’t see the relevance of this point (I think it’s about accuracy) so I’ll make my own point. (Besides which, my dictionary doesn’t contain the word multilateration.)

When I left the FAA, our radar scopes were big (I think 20 inch) monitors. They were really nothing more than a fancy TV or computer screen. The targets (depending upon the range settings) were anywhere from one half mile wide to a full mile wide. It didn’t matter if the target was a Cessna with 33 foot wingspan or a Boeing 747 with a 200+ foot wingspan -- they were all the same size. If we ever move to cockpit-based separation, the pilots will be using what -- 10-inch displays ? 12-inch displays ? Granted, ADS-B is more accurate than radar. But how useful is that accuracy when the target is two miles wide because of the range setting on your display ? I won’t even get into the extra skills a pilot will need (think training and wash-out rates) or the distraction from the pilot’s primary duty -- flying the airplane.

”RNP routings, trajectory tracking and planning can give very accurate four-dimensional paths for use in automation and displays. “

Right up until a thunderstorm gets in the way. Besides, we’re now getting off track. The title of the article was “Air Traffic Safety vs. Capacity” and the main point was that runway arrival rates were the main limits to capacity. “Planning” on the “trajectory” for an arrival on final is real simple -- draw a straight line to the runway.

”Wake vortex detection and tracking could show where wake hazards are—and aren't. (This is the one area that still needs advances in technology.) “

That’s a fair statement. We’ll talk again when the technology is fielded and see how much it will increase runway capacity. I would make a totally uneducated (remember, I wasn’t a Tower controller) guess and say less than 10 percent.

”With these items in place, we could safely operate with more than one plane on a 10,000-foot runway, especially with departures.“

Let me use Mr. Lewis’ own words to answer this one.

”...runways have capacity limits only with respect to the operating assumptions used. “ Where does that leave us ? If we could safely and accurately plot wake vortices (we can’t yet) we could put more than one airplane on the runway at a time. Sometimes. If we had the entire airline fleet equipped with synthetic vision we could start bringing the IFR arrival rates up to VFR arrival rates. Would-a, could-a, should-a. We could triple the width of runways and take off in formation like the military does.

Using the assumptions of today, we’re stuck with a certain capacity. Using the assumptions of tomorrow, we’ll be stuck with a certain capacity (hopefully a better one.) Whatever that capacity is, I am 100% certain -- for the places that matter, like New York and Chicago -- we will use all of it. To steal a line from a movie, If you build it they will come. And there will still be more capacity in the sky than on ground. Runways will still be the limiting factor. And safety will still be the determining factor in how those runways are used.

The question we seem to arguing over is, “What shall we build ?” The tax payers are being asked to pony up 20+ billion dollars (emphasis on the +). Boeing is not in the runway-building business (at least I don’t think they are). The Reason Foundation is in the privatization business. I’m not in any business at all. I’m a retired public servant with the quaint notion that we ought to ask how the public would best be served.

The pay off for the public’s investment in NextGen hasn’t been defined any better than the cost. What is the percentage of improvement NextGen will provide in runway arrivals rates ? The proponents think it will improve the current IFR arrival rates to nearly the current VFR arrival rates -- in 20-25 years. I believe the percentage of improvement NextGen will provide for the current VFR arrival rates will be virtually ZERO. However, an additional, properly-built runway substantially increases the IFR and the VFR arrival rate. Even the FAA can get this one right.

According to the Federal Aviation Administration, the new runway, opening May 27, will increase by about 30% the number of arrivals the airport can handle at any time, reducing passengers' average waits as they taxi or circle in the air. “

Bear in mind that’s a 30% improvement at an airport that already had 4 parallel runways.



If you ask NextGen proponents the plain and simple question, “By what percentage will NextGen improve the VFR arrival rate at XXX airport ?” the answer will be a deafening silence. There will be a multitude of non-answers explaining that NextGen is so much more than that and those types of things are yet to be determined.

Let me close by making one last point -- one about attitude. To me, this quote sums up Mr. Poole’s attitude.

”If controllers genuinely believe the kinds of things Brown wrote, that's a big problem by itself, since they and their successors will be key participants in making NextGen a reality. And if they are not brought on-board and decide to oppose NextGen implementation efforts on safety grounds (the theme running through Brown's post), we will need a major educational communications effort to explain to reporters and editorial writers (and members of Congress) that the new paradigm not only increases airport and airspace capacity but does so simultaneously with increasing safety.”

In short, if the controllers don’t agree with him, Mr. Poole believes he needs to go around them. Nothing makes this point clearer than his consultation with Mr. Lewis of Boeing ATM. No offense to Mr. Lewis -- as I said yesterday I’m sure he’s an exceedingly bright individual -- but unless he has worked a substantial length of time as an air traffic controller, he isn’t an expert in air traffic control. I have no doubt that he is an expert on the systems that might come to be known as NextGen.

As I’ve pointed out at least twice in the last two days, I am not an expert on airport air traffic control. Yes, I know a great deal about it. I’ve spent more hours in Air Traffic Control Towers than I can count -- starting when I was 16 years old -- bugging the controllers with endless questions. Even after 25 years as a controller in the FAA, if I have a question about air traffic control operations around an airport, I still consult with the only true experts -- the controllers that work in those Towers. The fact that I do -- and Mr. Poole didn’t -- speaks volumes.

He has company though. The FAA stopped consulting with their controllers too. Considering the mess we’re in now, I’ll let the public decide if that is a wise course of action.

Don Brown
March 14, 2008

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