Flarm Thoughts After the 2012 Racing Season

First, (to paraphrase a late infamous U.S. president) let me be perfectly clear about this. I am not a Flarm expert (although I do have an advanced degree in RF propagation theory and was an active antenna designer/researcher in a a past life).  I have no financial or other interest in Flarm outside that of a soaring enthusiast and contest pilot wannabe.  I have been accused, with some justification, of exaggeration, prevarication, over-emotionalism, and outright fabrication in some of my posts. Anything you read from me should always be taken with several grains of salt, viewed with skepticism, and independently verified to the degree possible. In fact, my best advice to you is to stop reading right here, as otherwise you are sure to be dragged into the Flarm controversy where brother is arrayed against brother, Schemp-Hirth aligned against Schleicher, and Club Class vs FAI (well, maybe not quite that bad). I have included this lengthy (and somewhat tongue-in-cheek) disclaimer as I know that this post is sure to generate lots of controversy – you have been warned! ;-).

My intent here is to describe relevant experiences from a full season of contest flying with Flarm, starting with the Seniors last March and ending just last week with the Region 4 North contest in Fairfield, Pa, and then to pontificate a bit about the impact (or lack thereof) of Flarm on the U.S.  glider racing scene.

This story actually starts late in the 2011 racing season, as some of us received portable Flarm units in time to fly with them at the Uvalde Pre-Worlds in August.  This was all very new, and nobody really knew what was going to happen. Installations were actually pretty easy, as the portable units could basically go in only one place—front and center on the glareshield. Powering the units was a real issue, as the darned things ate batteries at a furious clip.  A set of 4 Alkaline AA batteries lasted just one day (I tried to stretch to two days one time, and that was a disaster).  Although some pilots went the rechargeable route, I just bought a 24-pack of alkaline AA’s at the local Wal-Mart and put new ones in every day. Performance was spotty, but since we didn’t really know what to expect, we all thought that was normal. After a week of flying with the things, I think the general reaction was a big yawn – they didn’t really offer a whole lot more performance than the MkII eyeball, and often less. Although I flew with my portable unit for the rest of the 2011 season, I was usually either the only Flarm equipped pilot at a contest or one of just a few others – never enough to get any sense of functionality.

Seniors Championships, March 2012:

By the time the Seniors rolled around in March, there had been a lot more Flarm deliveries to pilots over the winter months, and I think about 25-30% of the pilots showed up with Flarms (all portable units, as the ‘brick’ still had not shipped). In addition, Dave Nadler (YO) of SN-10 fame and more recently heavily involved in the introduction of Flarm was there, so we were getting information straight from the horse’s mouth, so to speak.  In the two weeks of practice before the contest, and during the contest itself, we all had plenty of opportunities to see how this new whiz-bang actually worked.  About halfway through the contest, I became convinced that there was something fishy in Denmark, and there was a real range issue that wasn’t being acknowledged or addressed.  On several occasions I had the opportunity to fly with several different gliders that I knew were Flarm equipped, and on those occasions I went out of my way to fly a parallel path at more or less the same altitude, and at various distances from about 100yds to a mile or so (all judged by eye).  I would move away until the other plane’s symbol disappeared, and then move back in closer until it reappeared.   What I discovered was that effective range was well less than 1 mile, and quite often less than 100yds.  Then I started polling the other Flarm equipped pilots and learned that they were experiencing much the same problems.  As a result, a number of us basically cornered Nadler and beat on him until he (and by extension Flarm) started taking us seriously.

Perry (R5N), April 2012

As part of my Soaring Cafe reporting from the Seniors, I had of course reported about the perceived range issue.  In a wrapup post, I suggested in my normal laid-back style that Flarm had better get its act in order and at least *appear* to be working hard on the problem, or the entire Flarm effort in the U.S. could grind to a halt.  I also suggested that the Perry contest would be a good place to start that effort.  To their credit, the Flarm team, again working through Nadler, showed up at Perry loaded for bear. Nadler brought some diagnostic logging software that he loaded onto several of our portable units early in the contest.  During the contest, he spent many hours each night crunching through the data and then briefing us on his findings the next day. By the end of the contest, I believe Dave and Flarm were fairly confident that they had identified a prime suspect and were getting ready to make an arrest.

Mifflin (15 meter nationals) – May 2012:

By the time the 15 meter nationals rolled around in May, the Flarm team was fairly confident they had a solution to the range problem, and Mifflin was to be the proving ground. The first few ‘brick’ units were available, and were being distributed to competitors who had ordered ‘brick’ units so long ago.  Dave Nadler was back as the Flarm rep, collecting more data and helping with brick installations on the (unfortunately many) rain days. As one of the Uvalde pilots who had accepted a portable unit as a temporary substitute for my originally ordered brick, I was understandably out of the running for a brick delivery at Mifflin, but I did get to fly with a Nadler test portable that had one of the two Flarm channels modified with the range fix, and the other left unmodified as a control.  Wow, what a difference – all of a sudden I was surrounded by hordes of gliders, all intent on making me nervous!  Seriously, until you have a working Flarm unit on a contest day in restricted visibility, you cannot appreciate how much you are missing with the MkII eyeball. At one of the pilot meetings Dave briefed us all on the results of the data collection effort from Perry and the subsequent modifications to the brick units to address the range issue. As I understood Dave’s briefing, the RF spectrum in the U.S. is much more crowded than in Europe, and the Flarm receivers were being desensitized (essentially jammed) by all the noise – kind of like trying to hold a quiet conversation at a very loud party.  The fix was to install a Surface Acoustic Wave (SAW) filter to block out all the extraneous stuff, so the Flarm information could get through.  Flarm was clever enough to have designed in some space on the printed circuit boards for a SAW filter, but didn’t put them in until they knew they had a problem.  One the last day of the contest, Dave had one brick unit left over, so I was able to exchange my portable for a brick.

Dansville, New Castle, Fairfield (August, September, October)

In all three of these contests, there were sufficient numbers of Flarm-equipped gliders to provide some additional operational experience, and to (at least for me) drive home the significant improvement in safety. At Dansville we had a number of days with very good streeting, and the tasking unfortunately encouraged opposite-direction traffic under the streets (the same configuration in which OC was killed in Uvalde). Without Flarm, it was almost impossible to see head-on gliders in time to do anything when everyone was cruising up near cloud base. With Flarm, however, it was generally a piece of cake to mutually avoid each other.  At New Castle I was heading for a marked thermal near the airport before the start, and as I approached I was concentrating on merging cleanly with the gliders already in the thermal and slightly above my altitude.  Another glider was approaching the same thermal from almost the opposite direction at my altitude, and was apparently doing the same thing I was, i.e. concentrating on merging nicely with the traffic. Consequently neither of us saw the other until our respective Flarm units alerted us of the impending head-on collision. When the alarm sounded (and believe me, it gets your attention) I glanced down to see the ‘circle of circles’ display showing an imminent collision danger at my 11:00 position and co-altitude.  Even with a pointing guide, it took me a second or two to see the head-on profile of the other glider, as it was partially obscured by the terrain background and haze, but I still had time to take appropriate evasive action. At Fairfield, Day 2 was a ridge day, and it was really nice to be able to see oncoming and/or overtaking traffic in plenty of time to take appropriate action (or non-action if it was clear there wasn’t a problem).  On the Tuscarora ridge there are a couple of places with ‘blind corners’ where one could easily meet another glider head-on with very little reaction time.  With Flarm, you ‘see’ other Flarm equipped gliders well before encountering them at a blind corner.

The Flarm Rental Program:

In response to an earlier Soaring Cafe post advocating an RC mandate for Flarm, I received an email from a young soaring pilot who was worried that the cost of a Flarm installation might prevent him and some others with limited budgets from competing in SSA sanctioned contests.  In my reply to him, I pointed out that Williams Soaring (http://www.williamssoaring.com/powerflarm/rent.html) offers a Flarm portable unit rental program.  Units are available for $50 per contest (and the $50 includes shipping from and back to Williams Soaring – what a deal!).  This program didn’t impact me directly as I already had a unit, but I saw it in action at a number of contests – the units were well packaged and even came with rechargeable batteries and a charger – thank you Williams Soaring for this wonderful program!


  • By the end of the 2012 contest season I believe it is obvious to all that Flarm works for it’s intended purpose – detecting nearby Flarm aircraft and providing timely warning of potentially dangerous situations, without unduly overloading the pilot when circling in gaggles.  Even with only 30-50% coverage of the contest fleet to date, contest soaring has already gotten significantly safer for Flarm equipped pilots than for non equipped ones.
  • There is now a significant body of operational first-hand evidence that Flarm is already alerting pilots of potentially deadly situations, and was doing so even in the face of the range reduction caused by the more crowded RF spectrum here in the U.S.  I have described several of the incidents I personally experienced, and I suspect that almost every other Flarm equipped pilot has similar stories.  It is more than a little disturbing to think about how many similarly dangerous situations I have encountered in the past without ever realizing they existed!


In the emotionally charged period following Chris O’ Callaghan’s death in 2010, there was a strong push to make Flarm mandatory for all contests, assuming that sufficient units (either permanent installations or portable units) were available, even though not a single Flarm unit had been delivered to the U.S. market.  This unfortunately caused a lot of polarization in the glider community, and ultimately led (at least in part) to one well-known contest pilot leaving the sport for good.  In response to all the controversy, the SSA Rules Committee (RC) eventually published a ‘white paper‘ laying out the RC’s understanding of the state of play for Flarm, and their position on the matter of mandating Flarm usage in sanctioned contests.  At the time (and now, for that matter) I believe the RC did a great job in handling a very emotionally charged and controversial issue in a very professional manner.   The problem facing the RC was the lack of real data regarding the specifics of Flarm performance or delivery schedules, and the Flarm organization wasn’t really in any position to provide such data due to the vagaries of the required FCC certification process.  It could be months, or years before anyone saw real Flarm units.  In addition, there were (and are still) many open questions about possible unintended impacts to the nature of glider racing (I might interject here that, according to the RC white paper cited above, the European crowd has tended to favor non-stealth over stealth mode, evidently concluding that the downsides of stealth outweigh any perceived benefits).

Two years later, in the fall of 2012, A significant percentage of the competition glider fleet is already Flarm equipped, and we have a large body of operational experience gained over this past competition season.  I now think we are in a position where a re-examination of the RC’s position with respect to Flarm implementation is in order, and I understand the RC is in the process of doing just that.  I have also heard that the RC is planning to poll pilots for input on their experiences with Flarm, but haven’t yet seen anything definite in this regard.  In the meantime, while waiting for the RC to complete its deliberations, I offer the following thoughts.

  • It is absolutely 100% obvious that Flarm works and has already significantly enhanced soaring safety, especially in the contest environment.  After just one season, I am amazed at how many close calls it alerted me to, and horrified to think that this same rate of close encounters has to have been happening all this time, with me completely unaware of the lurking danger.
  • I have heard some folks say that Flarm shouldn’t be pushed/mandated because it ‘isn’t fully functional’ in that the promised IGC recorder isn’t yet available, the ‘secondary software’ that allows Flarm information to be displayed on other devices isn’t ready, and the alert volume isn’t high enough on the Butterfly displays.  While these complaints may have merit, they have no impact at all on the primary Flarm function, which is to display the positions of nearby Flarm equipped aircraft and to alert the user of potentially dangerous situations.
  • Parachutes have been mandatory for contest flying in the U.S. since long before I got into the sport in the mid 90’s.  I have no way to know for sure, but I’ll bet that some of the arguments I have heard for and against a Flarm mandate were used for and against a parachute mandate.  Clearly the RC of that era felt that the improvement in contest flying safety offered by the use of parachutes outweighed any arguments against such a mandate.  Comparing parachutes and Flarm:
    • The primary function of both parachutes and Flarm is directed at mitigating the dangers associated with a midair collision – the parachute by giving the pilot an exit plan, and Flarm by preventing the midair in the first place.  It would seem obvious to me that, assuming both are effective at their primary functions, Flarm is the better  choice (I am *not* advocating the removal of parachutes from contest cockpits – just that Flarm and parachutes address the same danger)
    • Parachutes and Flarm represent approximately the same financial barrier to entering competition.  The cost of Flarm has been cited as one reason to not mandate its use, but the parachute mandate had a similar ‘cost barrier’.
    • Most parachutes provide zero benefit for their entire lifetimes.  In other words, most of the money spent on parachutes, both for the initial purchase and for lifetime maintenance, is completely wasted (and that’s a *good* thing).  In order for a parachute to earn its keep, something like a midair has to happen that renders the glider unflyable, *and* the pilot has to survive whatever happened with sufficient functionality to get out of the glider, *and* this all has to happen at a sufficiently high altitude that the parachute has time to open before the pilot hits the ground, *and* the parachute has to actually work.  As we know from all too many accident reports, the probability of all four of these factors lining up is quite low.  So, we already have an RC-mandated,  significantly expensive piece of required safety equipment in our gliders from which we almost never derive any benefit.
    • Flarm, on the other hand, while costing about the same for installation and maintenance as a parachute, delivers significant benefit on almost every contest flight.  Moreover, the only requirement that needs to be satisfied for Flarm to operate properly is for most or all of the other gliders in the same vicinity to also have Flarm.  Compared to everything that has to happen for a parachute to deliver its intended benefit, Flarm has a much higher probability of success and a much higher level of ‘bang for the buck’ than do parachutes.


As I understand the SSA RC’s position, it is to not require Flarm, but rather to let common sense and ‘social pressure’ operate over a period of years to, hopefully, produce a situation where all or almost all gliders at a contest have Flarms, either permanently installed or rented.  A mandate would be considered only if the common sense/social pressure route fails to produce the desired result.    In the 2010 white paper, the RC stated a concern that a premature mandate might cause some pilots to dig in their heels and not install Flarm as a matter of principle, where they might otherwise succumb to a more collegial approach.  It occurs to me that something similar may well have been tried in the case of the requirement for parachutes, but we still ended up with a mandate .  I can think of three possibilities for the future of Flarm in the U.S. racing scene:

  1. FLARM is almost universally adopted in the next year or so, and ‘social pressure’ persuades any holdouts to rent/install units.  In this case, an RC mandate will serve only to affirm the de-facto situation (and maybe dissuade backsliding) and has no apparent downside.
  2. Same as above, but there are a number of holdouts who, for one reason or another, insist on coming to contests and flying without FLARM, and for whom ‘social pressure’ is ineffective.  In this case, I believe an RC mandate would force those individuals to stop competing or get with the program; either result is fine with me.
  3. For some reason, technical or otherwise, FLARM fails to live up to its promise, and adoption slows/stops/reverses.  In this case, any RC mandate can just as easily be modified and/or rescinded as enacted, and FLARM can be allowed to wither away.  I personally don’t think this is a very realistic possibility, but what do I know? – maybe ADS-B suddenly becomes a reality, and $50 ADS-B in/out devices become commonplace.

Assuming that the three cases above are reasonably comprehensive, what strikes me is that an RC mandate has almost no downside.  Even if the RC’s stated fear of causing some sort of a backlash were to happen, I’m not convinced that wouldn’t be in the best interests of the sport.  Do you really want to be flying in a contest with someone who can afford to install a Flarm system, but doesn’t out of a matter of principle?  What would that principle be – “I demand the right to be an undetectable menace to everyone at this contest? ” Or maybe “I’m so concerned that TA will be able to leech off me that I’m willing to risk my life (and everyone else’s!) to prevent it? ”

As in all my Soaring Café posts, these thoughts are entirely products of my own fevered imagination and are not the official line of any organization or entity.  I put them down because I think an open and vigorous debate about the future of Flarm in the U.S. would be a good thing, and because I think my experiences with Flarm during the 2011 and 2012 seasons are illustrative.

If you have managed to read this far without nodding off to sleep or ruing the day TA was born, I would urge you to add your voice to this debate, especially if you have relevant first-hand experiences (good or bad) to share.  Assuming that the promised RC poll becomes a reality, I also urge you to make your thoughts known there, too.  The current RC is comprised of highly experienced and professional racing pilots, and I’m sure they would appreciate as much relevant input as they can get.


Frank  (TA)


  11 comments for “Flarm Thoughts After the 2012 Racing Season

Comments are closed.