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September - Yet another update on FLARM Report by Peter This is part of what I said in my last report on the Flarm - "My frustration with the Flarm was that in very high traffic density situations, like pre-start gaggles, the audible and visual warnings were annoying and distracting. I'm sure that minor updates in the firmware relating to the algorithms or sensitivity can minimise such warnings (note that these are not 'false alarms' since in each case I was in relatively close proximity to other gliders)." Well, the Flarm already has these "minor updates" and more! See the response below from Urs... "Just another quick response to your report. Unfortunately you were not given instructions/the manuals, as Flarm has a simple way to change volume: by pressing the button it goes from loud to medium, low, silent and back to loud. Furthermore if you doubleklick the button Flarm will not issue *any* alarms for 5 minutes. This can be quite useful in gaggles/competitions. We are still improving the algorithms to reduce the number of needless alarms when many gliders are around. For this we have added a barometric sensor (to aid the GPS) but the software to use it for collision prediction is not yet finished. It will give us a much better input to judge vertical seperations which are important when circling." So my only reservations about the unit have been shot down as due to operator error. The Flarm is fantastic, the designers have thought of everything and have packaged it in a neat and reasonably priced unit. There are remaining spectrum licensing issues in Australia and Flarm Technology are considering a way forward. They'll publish their findings soon. Let's hope there are no showstoppers and we can get Flarms into service in Australia ASAP. 17 August - Update on FLARM Report by Peter Following the report of my experience flying with a Flarm (see the report of 29 July), I have received further information from Urs Rothacher from Flarm. During the Vinon pre-world competition the Flarms that were made available (free of charge) to the competitors had firmware version 2.1.0. This version of the firmware produces ghost obstacles, which explains some of the false alarms I was getting. Later versions of the firmware have corrected the problem. My experience flying with a Flarm was not entirely positive, however I am a strong supporter of the concept. I can recall several occasions during the contest that the unit alerted me to a potential collision with another glider that I had not seen. Maybe the other pilot had seen me, maybe not. How many close calls do we have on our flights that we don't even know about? My frustration with the Flarm was that in very high traffic density situations, like pre-start gaggles, the audible and visual warnings were annoying and distracting. I'm sure that minor updates in the firmware relating to the algorithms or sensitivity can minimise such warnings (note that these are not 'false alarms' since in each case I was in relatively close proximity to other gliders). For flying in Australia, I'd be one of the first to buy a Flarm if I knew that a significant number of the gliders in Australia would be so equipped in the near future. And there's the problem - we need a significant percentage of the gliders equipped with a Flarm before we'll see much benefit. We are in the process of trying to negotiate a loan of Flarm units for the multi-class nationals at Gawler in January, hopefully also for the club class nationals at Benalla. If this works out it will be an excellent opportunity to evaluate the system under Australian conditions. For further information on Flarm, take a look at http://www.flarm.com/product/index_en.html 29 July - FLARM Report by Peter I've now had 10 flights with the FLARM and it's time to report my experience with it. For those not familiar with the device, the FLARM is a GPS enabled unit that transmits its position to other aircraft and receives transmissions from other FLARM units. It displays the relative location of aircraft in close proximity and generates audio alerts if there is an imminent possiblity of collision. The FLARM also contains a database of cables and powerlines and provides alerts if the aircraft is in close proximity to one of these. The FLARM concept was originally developed in France but is now manufactured and marketed from Switzerland. It has widespread use in gliders in Switzerland and a growing number of gliders in France. Even so, less than 50% of the gliders that I have flown by have had a FLARM unit, I have found the FLARM to be of most benefit when I am not already aware of the close proximity of other gliders. Examples are when I am thermalling and another glider joins the thermal, or a head on situation with two or more gliders on a ridge. The skies here are very busy and it gives some peace of mind to know that the FLARM can warn some dangerous situtations. It can never be relied on, however, since not all gliders have the unit and almost no powered aircraft. During this competition there have been several conflict situations that I was not aware of and for which the FLARM correctly gave a warning. The downside is that, in my opinion, the FLARM is too sensitive. I find it hard to concentrate, hard to hear the audio vario, and hard to communicate over the radio when near a large number of gliders. In the pre-start gaggles we often have around 50 gliders, all in the same thermal at much the same height. The FLARM audio alarm goes off constantly and is very loud with no volume control. In a cruise situation the sensitivity is even higher and it will warn of gliders with a height separation of many hundreds of feet - I really don't care if a glider is about to pass 300' above me. I have found the cable warning to be next to useless. Firstly the database for France only has a small fraction of the cables in it (and some cables in the wrong place). But the main problem is that it does not seem to take the altitude of the cable into consideration. When I am flying at 10000' I don't need to be warned that there is a cable across the valley 8000' below me! The FLARM is of most benefit in densely populated skies and where most of the aircraft are equipped with the unit. In Australia our skies are generally not busy, with the exception of circuit areas and competitions. There may be justification for introducing the unit for competitions. For more general use in Australia I'd wait for a year or two until the technology stabilises and there is more experience with its use in Europe. |