Nostalgia: Airspace Edition. The end of the road for VORs

The FAA is in the process of redesigning the Class B airspace around SFO airport, and it signals an interesting  shift in air navigation: the requirement that everyone in the airspace be able to navigate by means of GPS.

They are undertaking the redesign primarily to make flying around SFO quieter and more fuel efficient. The new shape will allow steeper descents at or near “flight idle” — meaning the planes can just sort of glide in, burning less gas and making less noise. As a side benefit, they will be able to raise the bottom of the airspace in certain places so that it is easier for aircraft not going to SFO to operate underneath.

As far as I’m concerned, that’s all good, but I noticed something interesting about the new and old design. Here’s the old design:

This picture, or one like it, will be familiar to most pilots. It’s a bunch of concentric circles with lines radiating out from it, dividing it into sectored rings. The numbers represent the top and bottom of those sections, in hundreds of feet. This is the classic “inverted wedding cake” of a Class B airspace. In 3D, it looks something like this, but more complicated.

This design was based around the VOR, a radio navigation system, that could tell you what azimuth (radial) you are relative to a fixed station, such as the VOR transmitter on the field at SFO. A second system, usually coupled with a VOR, called DME, allows you to know your distance from the station. Together, you can know your exact position, but because of this “polar coordinate” way of knowing your position, designs intended to be flown by VOR+DME tend to be made of slices and sectors of circles.

The new proposed design does away with this entirely.

Basically, they just drew lines any which way, wherever it made sense. This map is almost un-navigable by VOR and DME. It takes a lot of know twisting and fiddling to establish your exact position if it is not based on an arc or radial. Basically, this map is intended for aircraft with GPS.

All of this is well and good, I guess. GPS has been ubiquitous in every phone, every iPad and every pilot’s flight bag for a long time.

I learned to fly in a transitional era, when GPS existed, but the aircraft mostly had 2 VOR receivers and a DME. My flight instructor would never have let me use a GPS as a mean of primary navigation. Sure, for help, but I needed to be able to steer the plane without it, because the only “legal” navigation system in the plane were the VORs. I still feel a bit guilty when I just punch up “direct to” in my GPS and follow the purple line. It feels like cheating.

But it’s not, I guess. Time marches on. Today, new aircraft all have built-in GPS, but a lot of older ones don’t. And if they’re going to fly under the SFO Class B airspace, they’re going to need to use one of those iPads to know where they are relative to those airspace boundaries. And strictly, speaking, they probably should get panel-mounted GPS as well.



ATIS in your kitchen

One ritual that every pilot observes before launching into the wild blue yonder (or dark gray muck) is tuning in the Automated Terminal Information Service, or ATIS. The ATIS is a recording, usually updated hourly, that contains a very terse version of the current weather and anything else new that pilots need to know.

ATIS is not the first weather information a pilot will hear before flying. In fact, it is more likely to be the last, after she has gotten a complete legal weather briefing (14 CFR 91.103), but before taking off.

A similar system, called AWOS (Automated Weather Observation System) is like ATIS, except that it usually only carries the weather (no other info) and always sounds like a robot.

As it turns out, I have a doohickey in my home that 1) can connect to the Internet to get the weather and 2) sounds like a robot. I thought, maybe it would be fun to write an app that simulates ATIS on an Amazon Echo.

Well, here it is.

This is a rather straightforward Alexa Skill. A user specified the airport of interest by using its four-letter ICAO identifier. Standard ICAO phonetics are supported.

For example, Chicago O’Hare’s IATA code is ORD, but its complete ICAO code is KORD. You could say:

Alexa, ask airport weather to get kilo oscar romeo delta.

And it would read you the weather in Chicago. The skill also knows the names of many airports and will try to fill in that fourth letter if you only give it three. For European users, you can get the visibility and altimeter settings in metric.

A few details of the skill:

  • written in node.js
  • Uses the Alexa Skills Kit API — Amazon handles all the voice stuff
  • Runs as a function in AWS Lambda
  • Accesses weather data from ADDS.
  • Stores user preferences in an AWS DynamoDB (a Mongo-like thingy)
  • Caches weather info from ADDS for up to 5 minutes to reduce load on ADDS
  • Whole thing runs in the AWS “Free tier” — which is important, as I’m not going to spend money to host a free app.

One of the more fun aspects of the project was getting to maximal verisimilitude. The ADDS weather source actually provides a METAR, which has a lot of the same information as does the ATIS, but it’s not entirely the same in form or content, so I had to do some translation and adjustment. For example, wind directions in METARs are true-north references, but in ATIS, they are magnetic-north referenced. In Northern California, where I live, that’s a 16.5° difference — not trivial. The program makes the adjustment based on the location of the airport and calculations from the World Magnetic Model.

So this METAR


 There is even code there to try to get the pauses and pacing to be realistic.

Anyway, code is not the cleanest thing I ever did. Such is the case when things start as personal hacks and turn into “sofware.” Check it out on github.

More instructions here:


The answer is always the same, regardless of question. (Civil Aviation Edition)

The Wall Street Journal had an editorial last week suggesting that the US air traffic control system needs to privatize.

It’s not a new debate, and though I will get into some specifics of the discussion below, what really resonated for me is how religious and ideological is the belief that corporations just do everything better. It’s not like the WSJ made any attempt whatsoever to list (and even dismiss) counter-arguments to ATC privatization. It’s almost as if the notion that there could be some justification for a publicly funded and run ATC has just never occurred to them.

It reminded me of a similar discussion, in a post in an energy blog I respect, lamenting the “dysfunction” in California’s energy politics, particularly from the CPUC.

What both pieces seemed to have in common is a definition of dysfunction that hews very close to “not the outcome that a market would have produced.” That is to say, they see the output of non-market (that is, political) processes as fundamentally inferior and inefficient, if not outright illegitimate. Of course, the outcomes from political processes can be inefficient and dysfunctional, but this is hardly a law of nature.

For my loyal reader (sadly, not a typo), none of this is news, but it still saddens me that so many potentially interesting problems (like how best to provision air traffic control services) break down on such tired ideological grounds: do you want to make policy based on one-interested-dollar per vote or one-interested-person per vote?

I want us to be much more agnostic and much more empirical in these kinds of debates. Sometimes markets get good/bad outcomes, sometimes politics does.

For example, you might never have noticed that you can’t fly Lufthansa or Ryanair from San Francisco to Chicago. That’s because there are “cabotage” laws in the US that bar foreign carriers from offering service between US cities. Those laws are blatantly anti-competitive and the flying public is definitely harmed by this. This is a political outcome I don’t particularly like due, in part, to Congress paying better attention to the airlines than to the passengers. Yet, I’m not quite ready to suggest that politics does not belong in aviation.

Or, in terms of energy regulation, it’s worth remembering that we brought politics into the equation a very long time ago because “the market” was generating pretty crappy outcomes, too. What I’m saying is that neither approach has a exclusive rights to dysfunction.

A control towerOK. Let’s get back to ATC and the WSJ piece.

In it, the WSJ makes frequent reference to Canada’s ATC organization, NavCanada, that was privatized during a budget crunch a few years back, and has performed well since then. This is in contrast to to an FAA that has repeated “failed to modernize.”

But the US is not Canada, and our air traffic situation is very different. A lot of planes fly here! Anyone who has spent any serious time looking at our capacity problems knows thUS and Europe have very different sources of flight delaysat the major source of delay in the US is from insufficient runways and terminal airspace, not control capabilities per se. That is to say, modernizing the ATC system so that aircraft could fly more closely using GPS position information doesn’t really buy you all that much if the real crunch is access to the airport. If you are really interested, check out this comparison of the US and European ATC performance. The solution in the US is pouring more concrete in more places, not necessarily a revamped ATC. (It’s not that ATC equipment could not benefit from revamping, only that it is not the silver bullet promised.)

Here’s another interesting mental exercise: Imagine you have developed new technology to improve the throughput of an ATC facility by 30% — but the hitch is that when you deploy the technology, there will be diminution in performance during the switchover, as human learning, inevitable hiccups, and the need to temporary run the old and new systems in parallel takes its toll. Now imagine that you want to deploy that technology at a facility that is already operating at near its theoretical maximum capability. See a problem there? It’s not an easy thing.

Another issue in the article regards something called ADS-B (Automatic Dependent Surveillance – Broadcast), a system by which aircraft broadcast their GPS-derived position. Sounds pretty good, and yet, the US has taken a long time to get it going widely. (It’s not required on all aircraft until 2020) Why? Well, one reason is that a lot of the potential cost-savings from switching to ADS-B would come from the retirement of expensive, old primary radars that “paint” aircraft with radio waves and sense the reflected energy. Thing is, primary radars can see metal objects in the sky, and ADS-B receivers only see aircraft that are broadcasting their position. You may have heard in recent hijackings how transponders were disabled by pilot — so, though the system is cool, it certainly cannot alone replace the existing surveillance systems. The benefits are not immediate and large, and it leaves some important problems unsolved. Add in the high cost of equippage, and it was an easy target to delay. But is that a sign of dysfunction or good decision-making?

All of which is to say that I’m not sure a privately run organization, facing similar constraints, would make radically different decisions than has the FAA.

Funding the system is an interesting question, too. Yes, a private organization that can charge fees has a reliable revenue stream and is thus is able to go to financial markets to borrow for investment.  This is in contrast to the FAA, which has had a hard time funding major new projects because of constant congressional budget can-kicking. Right now the FAA is operating on an extension of its existing authorization (from 2012), and a second extension is pending, with a real reauthorization still behind that. OK, so score one for a private organization. (Unless we can make Congress function again, at least.)

But what happens to privatized ATC if there is a major slowdown in air travel? Do investments stop, or is service degraded due to cost cutting, or does the government end up lending a hand anyway? And how might an airline-fee-based ATC operate differently from one that ostensibly serves the public? Even giving privatization proponents the benefit of the doubt that a privatized ATC would be more efficient and better at cost saving, would such an organization be as good at spending more money when an opportunity comes along to make flying safer, faster, or more convenient for passengers? How about if the costs of such changes fall primarily on the airlines, through direct equippage costs and ATC fees? Or, imagine a scenario where most airlines fly large aircraft between major cities, and an an upstart starts flying lots of small aircraft between small cities. Would a privatized ATC or publicly funded ATC better resist the airlines’ anti-competitive pressures to erect barriers to newcomers?

I actually don’t know the answers. The economics of aviation are somewhat mysterious to me, as they probably are to you unless your an economist or operations researcher. But I’m pretty sure the Scott McCartney of the WSJ knows even less.


Privatization, aluminum sky-tube edition

This Congress still has some must-pass legislation to complete.

That includes a reauthorization bill that contains a bunch of much-needed reforms for the agency. But they slipped in a doozey of a change: complete privatization of air traffic control. The plan is to create a separate government-chartered independent non-profit to run the whole show, with the intention, of course, that it will be run much more efficiently than the ZAN-ARTCC-ATOPgovernment ever could. I liked quote from an unnamed conservative groups from another Hill article:

“To us it is an axiomatic economic principle that user-funded, user-accountable entities are far more capable of delivering innovation and timely improvements in a cost-effective manner than government agencies.”

Axiomatic, eh? Well, I think I see your problem…

Anyway, it’s worth taking a step back to think about this proposal from a few different angles. First, let’s remember what the FAA does. Really, there are three main activities:

  1. Write regulations
  2. Allocate funds for aviation-related programs (AIP and similar) and
  3. Run ATC (Note: the FAA’s ATC arm is called “ATO,” but I’ll keep calling it ATC here)

Honestly, there has always been something of a conflict between the needs of air traffic control with safety as top priority and efficiency and cost as lower priorities, and the rest of the organization’s needs. It is a small miracle that the FAA’s ATC runs the safest airspace in the world. But miracle or not, it is a fact.

Furthermore, it is also true that ATC has been slow to modernize. This is for several reasons. First, yes, government bureaucracy, of course. But there are other reasons, such as having congress habitually cut and delay funding for new systems (NB: when you are on temporary reauthorization, you don’t buy new things; programs do not progress. You just pay salaries.) Another problem is that the old systems, as cranky and obsolete as they are, work, and it’s just not a simple matter to replace a working system, tuned over decades with new technology, particularly if you require no degradation in performance in the process.

So does this justify privatization? Will a private organization do better in this respect? Well, here are some ideas for thought, in no particular order:

  • a private organization will use fees to fund itself. This might be good, because they should be able to raise all the money they need, but then again, fees might grow without control. A private organization running ATC is essentially a monopoly. Government control is a monopoly, too — except that you can use the levers of democracy to manage it
  • a fee-run organization will be mostly responsive to whomever pays the fees. In this case, it would be the airlines, and among the airlines, the majors would have the most bargaining power. Is this the best outcome? How will small carriers fare when it comes time to assign landing slots or assign routes to flight plans? How will general aviation do under such a system? Will fees designed for B747‘s coming into KEWR snuff out the C172 traffic coming into KCDW?
  • Regulatory capture is a problem for any industry-regulating government entity. Does the appointment of an all-industry board of directors for a private organization that assumes most of those functions “solve” that problem making total capture a fait accompli?
  • Will this new organization be self supporting or will it still depend on government money? How will it perform when there is an economic or industry slump? If there is a bankruptcy, who will foot the bill to keep the lights on?
  • When the inevitable budgets shortfalls come, how will labor fare? Will they have to sacrifice their contracts in order to help save the company?
  • I don’t know, but I’m just guessing, that nobody at the top of the FAA’s ATC today makes a million dollars a year. Will it be so under an private organization? If so, where might that money come from?
  • Does an emphasis on efficiency server the flying public? To that matter, do the flying public’s interests diverge from those of the airlines, and if so, how are they represented in the new organization’s decision-making?

I honestly have not considered or study this matter enough to have a strong opinion, but so much of it causes the hairs on my neck to stick out.

I’ll give the authors of this new bill credit for one thing: they managed to get the ATC union (NATCA) on board, essentially by promising continuity of their contracts and protections. I’m not sure if that comes with guarantees in perpetuity. One thing I noticed immediately is that current employees would be able to pay into the federal retirement system. New employees…


[ Full disclosure: I am a general aviation pilot and do not pay user fees to use ATC, and like it that way. I do understand that this is a subsidy I enjoy. ]




Freedom from v. freedom to: aviation edition

The FAA is still in its rule-making process for drones (or as they call them, UAS — unmanned aircraft systems), but they have announced that all drone operators must register themselves and their aircraft online. There will be a $3 fee (waived for early-registrants until 1/20/2016) and the registration lasts three years.

A quad-copter, quad-coptering.
A quad-copter, quad-coptering.

Some drone enthusiasts and some libertarians are up in arms. “It’s just a new technology that they fear they can’t control!” “Our rights are being curtailed for no good reason!” “That database will be used against us, just wait and see!”

I have a few thoughts.

First, I have more than a smidgeon of sympathy for these views. We should always pause whenever the government decides it needs to intervene in some process. And to be frank, the barriers set by the FAA to traditional aviation are extremely high. So high that general aviation has never entered the mainstream of American culture, and given the shrinking pilot population, probably never will. The price to get in the air is so high in terms of training that few ever get there. As a consequence, the price of aircraft remains high, the technological improvement of aircraft remains slow, rinse, repeat.

In fact, I have often wondered what the world might be like if the FAA had been more lax about crashes and regulation. Perhaps we’d have skies filled with swarms of morning commuters, with frequent crashes which we accept as a fact of life. Or perhaps those large volumes of users would spur investment in automation and safety technologies that would mitigate the danger — at least after an initial period of carnage.

I think I would be upset if the rules were like those for general aviation. But in fact registration is pretty modest. I suspect that later, there will be some training and perhaps a knowledge test, which seems quite reasonable. As a user of the National Airspace System (both as a pilot and a passenger) I certainly appreciate not ramming into solid objects while airborne. Registration, of course, doesn’t magically separate aircraft, but it provides a means for accountability. Over time, I suspect rules will be developed to set expectations on behavior, so that all NAS users know what to expect in normal operations. Call it a necessary evil, or, to use a more traditional term, “governance.”

But there is one interesting angle here: the class of UAS being regulated (those weighing between 0.55 lb and 55 lb) have existed for a long time in the radio-controlled model community. What has changed to make drones “special,” requiring regulation now?

I think it is not the aircraft themselves, but the community of users. Traditional radio-controlled models were expensive to buy, took significant time to build, and were difficult to fly. The result was an enthusiast community, which by either natural demeanor or soft-enforced community norms, seemed able to keep their model airplanes out of airspace used by manned aircraft.

Drones came along and that changed quickly. The drones are cheap and easy to fly, and more and different people are flying them. And they’re alone, not in clubs. The result has been one serious airspace incursion after another.

A lot of people seem to think that because drones aren’t fundamentally different technology from traditional RC hobby activity, that no new rule is warranted. I don’t see the logic. That’s not smart. It’s not about the machines, it’s about the situation.

Anyway, I think the future for drone ops is actually quite bright. There is precedent for a vibrant hobby along with reasonable controls. Amateur radio is one example. Yes, taking a multiple-choice test is a barrier to many, but perhaps a barrier worth having. Also, the amateur radio community seems to have developed its own immune system against violators of the culture and rules, which works out nicely, since the FCC (like the FAA) has limited capacity for enforcement. And it’s probably not coincidental that the FCC has never tried to build up a large enforcement capability.

Which brings me to my final point, which is that if the drone community is smart they will create a culture of their own and they will embrace and even suggest rules that allow their hobby to fruitfully coexist with traditional NAS users. The Academy of Model Aeronautics, a club of RC modelers, could perhaps grow to encompass the coming army of amateur drone users.