From: Kim O'Neil (Director, Advanced Aviation Technology Ltd)

To: Darryl Phillips (AirSport Corporation)

Date: 8 June 2000

Dear Darryl,


I read your article at and whilst I think there is something in what you say (I agree 1090 is a disaster and not the way to do it) but I still don't understand your reasoning on identity.

I don't think a terrorist cares much about identity and there are simple ways of obtaining identity without ADS-B - especially with scheduled operations. I also don't think identity represents a terrorist threat to GA.......

On the other hand, I believe identity is required for functions like collision avoidance - since you need a simple way for two aircraft to exchange information to resolve a conflict eg exchange trajectory data (not just position and vector, but waypoints too).

As I have mentioned, I don't think 1090 is the way to go (and not very practical with GA operating at 25W and Commercial at 480-1000W). 1090 is too crowded anyway and adding ADS-B would adversely affect TCAS....

However, there is the possibility of low cost avionics based on VHF datalink. (I am not a vendor!) and this should be explored.

I hope you are not offended, but I wondered if your underlying problem is billing? In the US you get a lot of services free (which we in Europe don't!). Are you worried that ADS-B represents the "thin end of the wedge"?

If so, then there are solutions to the identity issue........ i.e a unique identity that can't be directly associated with you personally. A bit like hotmail...... Would this resolve the issue for you?

Best wishes,


From: Darryl Phillips (AirSport Corporation)

To: Kim O'Neil (Director, Advanced Aviation Technology Ltd)

Date: 8 June 2000

Thanks for your thoughtful comments, Kim. I agree with some of your points, disagree with others.

For many years I've been campaigning for deploying the various systems on different frequencies rather than everything on 1090. I like to think that my actions contributed in some small way to FAA's about-face regarding universal Mode S.

I have presented numerous seminars at aviation events such as Oshkosh, Sun'n Fun, AOPA, and Aircraft Electronics Assn, where I gave everyone in the audience a little "clicker" to represent a transponder. Then I get one person (an FAA employee if available) to stand up front with a flashlight (a torch to you guys!). He would scan the crowd with the light, they would click in reply. And just as in the real world, everyone would hear the clicks.

I begin with just a few airliners Mode A equipped, and there isn't much noise, everyone can clearly identify which person (aircraft) made the reply. Then I introduce Mode A to everyone, then Mode A/C (click twice), then more flashlight ATC interrogators.

Then I give the airliners Mode S. These are the party noisemakers with a ratchet that you whirl. The bedlam increases.

Then I introduce TCAS, where the airliners periodically and randomly ask" WHO?". And any aircraft that hears a "who" replies with a click.

As you can imagine, in a room with 200 prople, it really gets fun. Everyone quickly understands the problem. I have other visual aids, such as a scroll of paper with a Mode A/C reply (about 12 feet long) and one with a Mode S reply (about 70 ft long).

But I don't have to tell you about 1090 MHz, you know already.

ADS-B....Those scenarios at are -in part - the result of my frustration in trying to argue the technical points. In the FAA (and I assume their foreign counterparts)the engineers/technicians/planners only work on the tiny piece of the puzzle to which they have been assigned. And that portion, absent the other portions, works fine. At a higher bureaucratic level where the pieces of the puzzle all come together, we find bureaucrats rather than engineers, and these bureaucrats have no choice but to believe what their subordinates tell them: "My piece works correctly." There is no one in FAA who understands what all is going on, or how the parts relate to the whole. (For an exquisite and deadly example, read the words of ATC controller/pilot/aircraft owner Tom Lusch at .)

I think we need to plan for the future, not for the past. It is like the military mindset of always figuring out a better way to fight the previous war. ADS-B will exist in the future, and it must be structured to perform properly IN THE FUTURE. (Please excuse the shouting!!) Let me take several of your comments, and relate them to the future as I see it.

>>I don't think a terrorist cares much about identity and there are simple ways of obtaining identity without ADS-B - especially with scheduled operations. <<

I agree that a random terrorist (such as my scenario #1) doesn't care about aircraft identity. He can select a fat target by listening to the comm frequencies. At least he can today. In the future, with datalink (and hopefully a secure datalink) it may not be so easy. But I'll grant that a random act -by definition - doesn't require identification of a specific target.

That said, there is a great deal of terrorism difference between destroying just any 777 versus getting the specific 777 carrying a prominent head of state. In this example, identification is paramount.

As to the suggestion that "there are simple ways of obtaining identity without ADS-B", many of those ways (such as the ATC information available today on the internet) can be stopped at any time without affecting the aviation infrastructure. Not so with ADS-B, after it is implemented it will be the same as the rest of the aviation infrastructure, set in stone.

Step back from aviation for a moment and consider how we deal with terrorists today. We apprehend and prosecute after the fact. That is fine but doesn't address the problem. We also infiltrate or otherwise gain "inside information" before the fact. The agencies will try to get better at that, but so will the terrorists. One sure-fire way to avoid infiltration and betrayal is to operate as one sole person. No supplier of heat-seeking missiles, no collaborator to provide information from the airport of origin, no anyone at all, except the terrorist himself acting alone. This, in my view, is how terrorism will evolve. Groups can be compromised, supply chains or command chains can be compromised, single individuals cannot.

So, in that future world, how should we protect aviation from terrorism? Particularly from terrorists who, for religous reasons, don't mind being killed in the process? I suggest that we start by NOT building an enabling technology for them.

>>On the other hand, I believe identity is required for functions like collision avoidance - since you need a simple way for two aircraft to exchange information to resolve a conflict eg exchange trajectory data (not just position and vector, but waypoints too).<<

I think your statement divides into two parts, short timespan and long timespan. Obviously the mention of "waypoints" implies longer term, and is beyond the definition of collision avoidance. As I see it, collision avoidance is strictly a short timespan problem. Waypoints and all that involve something that falls under a different name than collision avoidance.

Short term, every aircraft already has a unique ID, namely it's position. If two aircraft have the same ID, then by definition they have already collided. And as long as they are still separated, they have a unique means of addressing each other for the purposes of data exchange. Other system constraints already argue for the least possible quantity of data in the message, this promotes capacity and robustness and so on. So, if the databurst already contains the necessary data, any further information (such as identification) is superfluous and contrary to our goals.

Longer term, the concept of "waypoints" presumes a type of regimented flight that is contrary to free flight and is contrary to the needs of general aviation and is contrary to the concept of freedom. It is an airline management tool. ATC is to the airline industry what Windows is to the computer. It has become the multitasking airline operating system rather than a means to implement maximum utility of the airspace. There is indeed a need for all the aircraft inbound to ATL to report their intention as soon as possible, even if they are hundreds of miles away. This will allow tiny changes in airspeed early in the flight rather than abrupt changes later for the purpose of sequencing landings.

But this is not collision avoidance, it is not data that should be exchanged between conflicting traffic, it is another animal and should be treated as such. ADS-B has fallen into the trap of trying to be all things to all people. It cannot, in my opinion. And in trying, ADS-B loses much more than it gains. It can be an enabling technology, adding to safety and utility and efficiency. Or it can be a restricting technology, restraining and regementing aviation and pushing general aviation further away.

Aircraft operation argues strongly for "least wind miles" or similar navigation that minimizes the time aloft. Only ATC argues for regimented lock-step flying along defined corridors. Man has known for a thousand years that a straight line is not the shortest path, if "shortest" is defined in time rather than distance. If Christopher Columbus had tried to sail on a straight line to the new world, he would have starved first. We need to be flying the path that gets us to the destination in the least time. This gives the best equipment utilization, burns the least fuel, and utilizes the airspace to the maximum. Less time enroute equates directly to fewer aircraft aloft at any instant, which certainly decreases the chance of collision. Randomizing the flightpaths does the same thing. So "waypoints" should not exist, at least not in a way that corresponds to the practices of today.

This is another example of how ADS-B is being structured to "win the prior war". If waypoints are part of the ADS-B equation, they will be required in the future to satisfy the needs of the box rather than the needs of aviation.

>>However, there is the possibility of low cost avionics based on VHF datalink... and this should be explored.<<

Yes. Personally I don't favor VHF for technical and cost reasons. With all the advancement being made today in L-band communications, there are components availalable for pennies that could not be duplicated at VHF. All around us, technology is moving higher and higher in frequency and I think it's wrong of us to try to cling to the past. But those are technical arguments which don't change the question of which data should be broadcast, and which should not.

>>I hope you are not offended, but I wondered if your underlying problem is billing? In the US you get a lot of services free (which we in Europe don't!). Are you worried that ADS-B represents the "thin end of the wedge"?<<

ONE underlying problem is billing. But please don't suggest that anybody gets anything for "free". Everything is paid for, nobody in ATC works without pay. But in the future, would you rather see European aviation move closer to what we have in the states, or would you rather see your massive GA problems extended to us?

Private aviation is one of the most freedom-intensive activities ever devised by man. That is why dictatorships and other repressive governments don't allow any personal aviation. Slowly we are losing it, not because anyone wants to take it away, but because we have fallen in a trap which says: (A)..All international flights must have some commonality; (B)...All airline flights must have commonality, regardless of whether they fly overseas or not; (C)...All aircraft must have commonality with the airliners.

This is absurd, the last few hairs on the tail are wagging the tail, which in turn is wagging the dog. Not the way it should be.

>>If so, then there are solutions to the identity issue........ i.e a unique identity that can't be directly associated with you personally. A bit like hotmail...... Would this resolve the issue for you?<<

No. It would not. History has shown, repeatedly and virtually without exception, that governments will take whatever they can get. In the case of ID, the "drug war" argument will be used, or some other argument will be used, that airplanes should never be anonymous. It is difficult, almost impossible, to argue to the contrary because you are immediately accused of siding with the drug dealers (or accused of being one yourself).

And this is not hypothetical, we have it with ADS-B right now. Quote from section of RTCA DO-242: "Identification. The ADS-B system design shall (R2.6) accommodate a means to ensure anonymity whenever pilots elect to operate under flight rules permitting an anonymous mode." What is implied is that there ARE flight rules permitting an anonymous mode. In the USA, (and I suspect everywhere) there are no such rules. It would require rulemaking to establish those rules, which in turn would require massive lobbying, which brings us back to anyone who favors freedom and anonymity being linked to druggies!

In my opinion, in this country there is virtually zero chance of such a rule being adopted. The airlines would not favor it, the military would be against it (although they practice it and will continue to), much of corporate aviation would see no advantage to anonymity, the chance that little GA could get such a rule adopted against such odds are slim to none.

The only way to guarantee anonymity is the build it into the box, in my opinion. If the box has unique ID capability, it will be used. History seems very plain on that point. Collision avoidance, in my opinion, means exactly that. It does not encompass oceanic position reporting, ramp scheduling, maintenance querys, or a number of other activities related to airline management rather than missing the traffic. ADS-B can be done in a way that promotes aviation, or in a way that hinders it. And not enough pilots and aircraft owners are paying attention to the difference.


Darryl Phillips

P.S.... Kim, I looked you up before writing this long response. What I would like to do is take your original message, this reply, and any further communication you would like to add, and post it intact on the AirSport website. For credibility, I would like to include your name. It can be done without your name if you prefer (but I hope you'll consider the parallel with the identification arguments above!!). I won't do anything until hearing back from you. Thanks, DHP

From: Kim O'Neil (Director, Advanced Aviation Technology Ltd)

To: Darryl Phillips (AirSport Corporation)

Date: 9 June 2000

Dear Darryl,

Wow. Slow down!!!!

There's too much in your note for me to do a point by point.....

The clickers sound fun and I absolutely agree with your point. Basically, big companies are trying to make big bucks by loading 1090 with functions it was never designed to support. It has been hopelessly over-engineered over the years.... (Actually, I think these companies know this, but are happy making hay while the sun shines!)

First off, let me agree with another key underlying point: we want less ATC intervention, not more. ModeS etc is part of an ATC lead campaign to extend ATC..... We don't think there is anything to gain by downlinking parameters, like heading, selected flight level etc. thats just ATC gone mad. (but the Mode S mafia are well established). Pilots should fly aircraft, not ATC.

However, we (in Europe) have also been working on concepts such as trajectory negotiation. This is not a pie in the sky, regimented system but a genuine attempt to work out how to achieve "Free flight" (this work is targeted to civil aircraft, but is applicable to GA too).

We think we can exchange trajectories and that this can be done between all types of aircraft. The most basic trajectory is a velocity vector, although this doesn't give much useful information to other aircraft. I stress other aircraft. For larger aircraft that know where they're going and have FMS, they can broadcast their intended trajectory every minute or so (its just a few bytes of waypoint data).

It can be achieved in GA aircraft too (if you stick to your flight plan......) The good bit is that you can change your flight plan as you go along....... As long as you output this new trajectory as soon as you "do it"! (which is why ID is useful - even a temporary ID).

This is an extension of ADS-B, but a very simple one. All other aircraft can receive this data (e.g. VDL4 range is 200 miles) and can decide if that or any other aircraft is in conflict (the algorithms for this are very simple). This gives plenty of time for any pilot that has a conflict, to resolve it with the other pilot (there are simple rules for doing this too) i.e. Free Flight.

Pilot goes where he wants, but must respect other pilot's intentions. If he has a problem with another aircraft then he has plenty of time to resolve it (say 10 mins instead of just 25secs.). I think this is as close to being FREE as it is philosophically possible to be. I am not proposing TCAS, although trajectory negotiation could do it better. (since it has intent data, TCAS doesn't).

ID is required but it doesn't have to identify YOU. It can be dynamically selected (although I prefer a static ID.....) A constant ID (for any particular flight) is very useful. But it could be a different ID for each flight....... (like the dynamic internet address assigned to you, each time you log on).

On the related issue of the FAA: I think FAA is in a mess. They are so preoccupied with "maintaining technological leadership" believing that they are protecting the interests of US industry (as if Honeywell, Rockwell etc need their help!) but, in fact, FAA lack the cutting edge knowledge required to play this game and consequently lumber from disaster to disaster, believing that they must do their duty at any cost (Hey! Now I'm getting out of control!).

Some of the places that they get their usual "technical" advice from have a vested interest in giving the FAA want it thinks the FAA wants to hear..... I could go on and on, but you'd soon get bored!!! A good example is the attempts to implement ADS-B in mode S extended squitter. What a hoot! Mode S range has been shown to be less than 20 miles in continental airspace due to excessive garbling and over interrogation. and what about the impact on TCAS? Doesn't bear thinking about!

I value this correspondence, as their hasn't been enough objective examination of some essential aviation issues. It is assumed that big agencies like FAA, Eurocontrol etc know what they're doing. But the only thing they seem to be good at, is trying to bull their way through one disaster after another (we've had a few here too!!!). Accountability? I don't think so.....

Best wishes,


******************* PS Please feel free to use this correspondence - I have no secrets! (At least none that I'm willing to talk about!)

The next ADS-B message comes from Jeff Bethel of UPS Aviation Technologies.  (I have inserted my rebuttals in blue - DHP)

Subject:      ADS-B
   Date:      Thu, 10 Aug 2000 18:12:52 -0700
   From:      "Jeff Bethel" <>
     To:      <>


Regarding your web site about ADS-B, there is some validity to your points, although, actually, not much.

As far as attempting to destroy an aircraft simply because it is squitting its present position and other people can pull that off the air, this seams like a real stretch.  This argument seems similar to the concerns that when SA was disabled for GPS positioning, now all those rouge nations could drop a nuke on the White House, within 10 feet.  It would take years and millions of dollars to research, develop and test a ballistic solution for launching and targeting a missile using GPS.  Why not just rent a Rider truck for $19 a day and they could do exactly the same thing - The point is, there are MUCH easier ways of accomplishing the goals that you allude to, without the use of ADS-B.  Just because something COULD be done in a certain fashion, does not mean it's rational to think that it is a real threat.

Agreed, there are "much easier ways" today.  And you can bet that lots of people are working to eliminate those easier ways.  Your example of a Rider truck is instructive, that is the brand used to destroy the Murrah building here in Oklahoma.  The result: barriers are now in place around many federal buildings, more monitoring cameras are in use, trucks are no longer allowed at many airport terminals, we are all under more surveillance as we move about, et cetera.

Can a Rider truck be used again?  Of course it can, and perhaps will. But each time it happens, restrictions on movement of peaceful citizens are tightened.  (Try walking into a federal courthouse today.)  Tightened security equals reduced freedom.  Fighting for freedom is not done in some jungle or desert on the other side of the earth, fighting for freedom is done where the freedoms are threatened, in this case by governments dealing with your "much easier ways".  It is incumbent on those who design systems of the future to be aware of the uses (and misuses) of that technology, and attempt to minimize the potential downside - including loss of freedoms that might result.  That is where I have problems with ADS-B.

BTW -  I think your comparison to SA and nukes is totally off the point.

Your argument makes as much sense as limiting public accessibility integrated circuits and gun-powder, because they COULD be used by terrorists to somehow use them in an elaborate scheme to take out an airliner.  ANY technology can be used for any purpose, but that does not mean that we should not implement the technology, especially one that is as safety advancing as ADS-B.

Exactly right, Jeff.  I don't want to see restrictions on integrated circuits or other materials.  But as our society drifts more and more toward "safety at any cost", increasing numbers of items are restricted.  When I was a kid, a Gilbert chemistry set had all sorts of dangerous stuff including poisonous and explosive materials.  In those days we had the FREEDOM to make our own mistakes and suffer (or benefit from) the consequences.  But some kids got hurt, and more laws were passed that reduced the freedoms of us all.  We need to plan our future in a way that minimizes our loss of freedom.

Waving the flag of "safety" (i.e. your statement "as safety advancing as ADS-B") is a warning that we need to beware.  The promise of safety has signaled the demise of a great many freedoms we no longer enjoy.

I spent an wonderful month on holiday in Australia last fall and the "safety" restrictions came sharply into focus.  A couple of examples:  In Sydney there is a beautiful bridge with a very high structure that arches over the harbor.  Climbing the thing was started by an adventurous few many years ago.  But instead of arresting them as would be done in this country (in the name of "safety"), climbing tours were organized!  It's still dangerous, you can easily slip and fall to your death, but that is a choice each individual is allowed to make.  The same was true at Uluru (Ayers Rock).  They used to place a bronze plaque in memory of climbers who perished but the number of deaths grew so now they have a book!  It was very windy when I was there, and no way was I going to climb, but the path was open and individuals could make their own choice.

These are illustrations of freedom versus "safety".

Sure, one could bounce a laser beam off the moon and blind the pilot and cause an accident, but think of all the things one could do with a silenced, high power rifle near any airport in the world - a much easier way than attempting to decode ADS-B transmission reports and build a radio controlled airplane that can knock down a 785,000 lb 747going somewhere between 200 to 500 mph.

"Attempting to decode"? Surely you jest.  ADS-B, as presently defined by RTCA DO-242, has no security at all. And bouncing a laser off the moon sounds like something dreamed up by the military!

In fact, this is so absurdly far fetched, it completely invalidates ANY of your opinions at all in my mind.  However there is more..

OK, Jeff.  You have some arguments that should be considered.  But character assassination doesn't aid your cause.

Do you feel that someone of a different skin color can have no valid opinions?  Or someone of a different religious faith?  Or someone who differs with you in any respect at all?  In other words, do you believe that someone who believes something that you consider "absurdly far fetched" cannot have ANY valid opinions?  I will assume that is not your position, else there would be no point in any discussion.

Most of your arguments seem to use the wording 'pinpoint accuracy'.

When your 'Dr. Whitten' found that the broadcast packet definition in all of those RTCA documents define position as somewhere within an altitude band of 100' with about 500' lateral accuracy (given the small payload capacity of the altitude and lat/lon values) - he realized that he is attempting to hit a target that is somewhere within 25 MILLION square feet of airspace - not small.  His heart sunk and the thought, surely there is a better way.  His mind wandered back to the $200 rifle and $2 bullet idea....

Jeff, I just went to my document and searched for "pinpoint accuracy".  Didn't find it.  So I searched for "pinpoint" and didn't find that word either.  So I assume you must have been reading things into the document that just are not there.

I'm sure you meant to say 25 million cubic feet, not square feet.  But that is not an appropriate way of calculating the risk, the need for cubic volume would only  apply if you need to also predict the exact TIME of collision.  If the bad guy is willing for the collision to happen a second earlier or later, then only the vertical and lateral accuracies are involved.  That is, the longitudinal component along the path of flight is immaterial, the problem resolves itself into a "headon" picture that only has height and width but not length.

I could not find altitude resolution defined in DO-242, but some systems proposed by Lincoln Labs and Mitre have used 25 foot vertical resolution.  This is substantially less than the height of an airliner.  Clearly the problem is different if the present 100 foot increments are retained but that hasn't been the talk so far. Likewise, there have been differing increments of horizontal resolution and accuracy, but your numbers of 100 ft high by 500 ft wide is only 50000 square feet, not 25 million.  And with 25 ft vertical resolution, it shrinks to 12500.

Regarding the broadcast of identification, this is mostly needed for IFR flight following services.  ATC needs to obtain positive identification that the target he sees, is who he thinks he is. It's critical to all types of operations in place today. It's exactly the same technique that the tens-of-thousands of existing transponders are operating in right now - and obviously with existing TCAS (Traffic Collision Avoidance System) technology, there is plenty of data being broadcast to both locate AND identify every transport aircraft in the air today ....

"Tens of thousands"??  I don't think so.  There are roughly 7000 airliners in this country, and they are all TCAS/Mode S equipped.  Beyond that, many bizjets and some others have Mode S but I doubt that the total number rises to 20,000+, the definition of "tens of thousands".

If every aircraft in this country were Mode S equipped, we would bring the ATC system to a complete halt.  FAA was tardy in realizing this but to their credit they did eventually understand that such an immense number of  Mode S replies would totally wipe out the system, and that is why the 1990's requirement ending Mode A/C and mandating only Mode S in new installations was delayed twice and then withdrawn altogether.

But your point - as I understand it - is that " there is plenty of data being broadcast to both locate AND identify every transport aircraft in the air today"  Not so, Jeff.  The Mode S Identification does indeed provide the ability to identify the aircraft and read it's altitude, but it does not provide any data on Lat or Lon.  That data only exists within the ATC system which is (hopefully) secured against unauthorized access.  Certainly the air carriers are not broadcasting it for everyone to intercept.

....- I can build a $5 homing receiver and actively home in on the broadcasting aircraft, right down to the patch of metal that the antenna is bolted to.   None of this has been abused to my knowledge, so I'm not sure why it's that much more of an issue with ADS-B.

Oh come now, a $5 homing receiver?  Have you priced just the enclosure?  Or the PC board?  Or the necessary phased antennae?  Or the power supply?  Or the active circuitry or output devices or......?  I'm sure if you have access to enough free parts and free test equipment you can do it for $0, but it won't tell you where that aircraft is.  As to the "homing" aspects, this is not nearly as easy as it sounds.  Remember that I make my living designing, manufacturing and marketing equipment that listens to transponder signals, so I have some idea of what is involved.  The duty  cycle of a sponder signal, even Mode S, is small and there are many other signals on the same frequency at the same time.  With pulsewidths of 450 nS (less than half of a millionth of a second, for those not familiar with nanoseconds), homing isn't that simple.  If it were, we would already have accurate and low cost collision avoidance equipment for the GA market.

In fact, ADS-B was modeled after the existing systems in this respect.

I disagree.  ADS-B is the first system to report 3D position and identification.  Mode S does not do that.  Nor does DME or TACAN or TCAS or ATCRBS or anything else now flying.  There is one exception, some airliners on oceanic routes now report 3D position via satellite but ADS-B certainly was not modeled after that system.

It's not the combined broadcast of position and identification that's new with ADS-B like you indicate, it's the ability for the pilot in one plane to know where the other plane is that is somewhere just above him, looming in zero visibility IFR conditions, that's new.

And I want that capability.  Aviation has needed the capability to see traffic for decades.  UAL's Bill Cotton first demonstrated such a system back in the 1940s - when television was brand new - by putting a TV receiver onboard and watching the ATC scope which was being televised by the local Boston station.  That was more than half a century ago and it is criminal that the FAA should put so many barriers in the way of progress.  We should have had the ability to electronically see our traffic long ago.

But when I want to miss the traffic, I don't care if it is United, or an F16, or only a Piper Cherokee.  I don't care who it is, I want to miss him.  I need as much information as I can get to help me avoid a collision.  Every piece of useless information is detrimental to that end because it clogs up the frequency and prevents some useful data from getting through.  I don't need his registration number, and I don't want that information taking up bandwidth.  Anything on the frequency which I don't need for collision avoidance is CONTRARY TO SAFETY.

Gosh, there is just so much on your page that is just plain absurd....

It's your perogative to think so.  I'm giving your point of view exposure - not a single word has been altered - I believe that each pilot can make up his or her own mind.  I'm also remembering that you work for UPSAT, the company that stands to profit handsomely from ADS-B, and therefore you have a bias.

Add my name to your 'hit list' - Jeff Bethel, UPS Aviation Technologies - and on the first abuse of ADS-B I'll admit I'm wrong.

I don't have a "hit list", Jeff.  I have posted the list of those who were involved in RTCA SC-186, the group that set the ADS-B standards.  But as to admitting that you are wrong after the first abuse, forget it.  It will be too late then, after the equipment is approved, after the regulations are adopted, and after the fleet is equipped, after the time and money are spent.

At that point we will be in the same position we are now with Mode A/C, where there is no difference between a squawk and an altitude databurst, which was the cause of the USS Vincennes shooting down the Iranain airliner and killing 300+ innocent civilians ten years ago.  In the case of Mode A/C, it would have been easy to use the "X" pulse to differentiate between the two reply types and those lives would have been saved.  But no one spoke out in time, the system was cast in stone, and we have to live with it.  That is one example, I could cite a dozen others that would have been just as easy to fix if technically qualified pilots had been given a chance to study the specs BEFORE they were adopted.

There are currently 150 aircraft in various stages of equipage in Alaska right now.  About 50 have been flying full-up ADS-B for about a year now (no-one has been shot down to my knowledge). The pilot feedback has been phenomenal so far - imagine being able to visually pinpoint an aircraft that is just a speck in the mist with a closure rate of some 400KT and knowing that by turning 2 degrees to the right, I won't die.

These are back-country, FAA leave us alone, get the government out of our face, we don't need no stinking high technology, fly by their ass, bush pilots we are talking about.  These same pilots are now requesting the ADS-B equipped aircraft when they fly because of the increased situational awareness that ADS-B is providing them. They feel safer because they are.   There are lots of people like you who think they technically grasp the systems and for some reason dream up squirrel brained ideas of how it could be twisted, but until you fly with ADS-B, you may never understand the real advantage.

The Alaska Capstone program is a demonstration, as you well know.  Those aircraft were equipped at the taxpayer’s expense (with a profit for you).  Again, as I said earlier, we need the ability to avoid the traffic and that function of ADS-B is great.

But why Alaska?  Is it a matter of traffic density that could not be handled in the LA basin?  The RTCA specs seems to point in this direction:

RTCA D0-242 Section 3.3.4 ADS-B Network Capacity
"The ADS-B network must be designed to accommodate expected future peak airborne traffic levels, as well as any airport surface units withing range.  The expected peak instantaneous airborne count (IAC) in the US has been given by the Los Angeles Basin traffic model [9,16].”

The two references are from 1974 and 1995, they don’t even account for the traffic of today, and certainly not the traffic of the future.

I submit that if the system won’t work at Oshkosh during the peak periods, it should be scrapped immediately, before any more taxpayer money is wasted.  I further submit that it needs to work at a traffic density several times that of Oshkosh if it is intended for the future.  Else ADS-B will become the limiting factor in the growth of aviation.  Designing a limit that prevents growth is damn absurd.

The RTCA specs are too long to reproduce here (aside from the fact that the document is copyrighted and therefore illegal to post on the web, another factor which limits user discussion).  But the RTCA traffic model also assumes 100 aircraft and support vehicles in motion on the ground, and 150 more not in motion.  Sounds reasonable, till you read further and see that the ADS-B specs assume a “homogeneous distribution over a radius of five miles...”

What airport is ten miles in diameter?  With "homogeneous distribution" of vehicles?  The numbers used to model ADS-B are beyond belief.  Yet they are being used, along with an experiment in Alaska, to determine the system under which the rest of us will have to fly.

(These systems all use the 'UAT' transceiver, not the 1090 band. They support the 'anonymous mode of operation that randomly creates an ICAO address, and can be turned off by the pilot at any point.  No FAA mandate required.)

Can be turned off by the pilot at any point”?  Don’t you mean they can be turned off if the rules permit it?  There was a time when we could fly without transponders too.  But little by little, the rules required more and more and more.  Is there anything inherent in the design of your ADS-B that prevents future changes in the regulations?  Of course not, we will be allowed or prohibited as the government sees fit, and those prohibitions will continue to change just as they do in the rest of aviation, and the rest of society.

ADS-B must be technically structured in a way that does not allow a future Big Brother to monitor our every move.  Not even in the name of “safety”.

The first fully certified General Aviation ADS-B system was created by myself and a handful of people that work under me.   I have been flying ADS-B equipped aircraft for some two years now and have yet to be been shot down because of it. The system works and it works great.  If your ever in the area, we can take you on an ADS-B equipped flight and perhaps you will see that the plain advantages that the system provides far far far outweighs the obscure scenarios you seem to worry about.

Two small GA aircraft just collided yesterday killing 10 people.

Jeff Bethel
UPS Aviation Technologies

Jeff, for the purposes of argument let us assume that identification does not result in any terrorism nor mayhem ever.  In all of your message I saw no mention of the other two scenarios, (1) data mining and (2) user fees.

Have you ever studied one of those long limousines you see in traffic?  Heavily tinted windows, no way to tell if the car contains one VIP or four or seven.  Or nobody at all.  Limos do not carry signs proclaiming who is inside, nor even license plates that give a hint.  Privacy is essential to the occupants whether they be from the world of politics or sports or entertainment or the mafia.

The same is true when they fly.  There is need for privacy and security.  Equipment that broadcasts the identification of the aircraft is contrary to that need.  Not just to give people their privacy, but to prevent monitoring by competitors. That is big business today, particularly between nations.  Many countries do not differentiate between “national security” and “corporate security” because anything that might threaten their major industries inherently threatens their national well-being .  For a strong aviation future, it is imperative that ADS-B not have ID reporting capability.

For most of us peons, however, the concern is different.  We worry more about user fees.  Airports need funding, what better way than taxing those who use the airport?  And what easier way than automatically monitoring the identification of all the traffic?  This takes no manual work, no new employees are required, the machine just spits out the airspace bills each month.  And us users will have to choose.  On the one hand is pay and pay and pay, on the other hand is dropping out of aviation.  Not a palatable choice.

Do you think that your “anonymous mode of operation that randomly creates an ICAO address, and can be turned off by the pilot at any point” will be allowed when user fees are involved?  If you are that naive, I have this bridge in Brooklyn you might be interested in purchasing......

So that sums it up, Jeff.  Technically we don’t need identification, it uses bandwidth that can be better employed.  Operationally we don’t need identification, every aircraft already has a unique ID, it’s position.  Aircraft can exchange data efficiently on that basis.  Security-wise we don’t need identification, we all know that Air Force One is not going to fly along reporting exactly who he is and where he is - and the same should apply to other aircraft.  And from a user fee standpoint it is imperative that we do not include identification.

The only entities that benefit from identification are the various governmental bodies.  They can use ID to track us, to bill us, to automatically charge us with infractions, to do other things which are great for the government but terrible for the people.

Personally, I’m on the side of the people.  Identification cannot be allowed, the future restrictions on our freedoms are just too big a price to pay.  And wrapping ADS-B in the flag of “safety” doesn’t change the smell.  Collision avoidance must not contain identification.

Thanks, Jeff, for permission to use your letter.

Darryl Phillips
August 2000
Would anyone care to join in? You can email Darryl or the other correspondents. Thanks.