On 11/09/2012 11:55, SoarTronic team wrote: > 2011 pilot's life was lost in gliding competition here in Finland. Both > gliders had FLARM installed, and they were in glide near each other > several minutes before collision. See the summary (English) of this > document; > http://www.turvallisuustutkinta.fi/Satellite?blobtable=MungoBlobs&blobcol=urldata&SSURIapptype=BlobServer&SSURIcontainer=Default&SSURIsession=false&blobkey=id&blobheadervalue1=inline;%20filename=Tutkintaselostus%20B1_2011L.pdf&SSURIsscontext=Satellite%20Server&blobwhere=1342016078074&blobheadername1=Content-Disposition&ssbinary=true&blobheader=application/pdf
This is a tragic, but interesting case study. One glider directly below and slightly ahead of another means they are both invisible to each other. Flarm would not display an alarm either, as there is no obvious impending collision. But when the lower glider pulls up in a zoom climb, the collision can happen very quickly. From illustration "Kuva 4" in that report, it is clear that the pilots were flying very close to each other for a period of time. They should have been aware of each other. The Flarm "nearest target" indication (LED's burning but not flashing and no audio alarms) would have done this, provided that functionality had not been deactivated. Also one assumes that experienced competition pilots would have been aware of each other - which is probably why they were flying so close together in the first place. One hopes that the Flarm logs from both gliders will be made available to the Flarm developers. Perhaps in a few years time there will be an upgrade to the software that allows a situation like this to generate a Flarm warning. As background to the comments below. Our club adopted the Swiss Flarm 7 years ago. More recently I have got XCSoar installed and much more recently a Dell Streak with a screen that can be read more often than not, and a IOIO/Flarm interface. I think it is important to understand that Flarm provides two types of data: a) Potential collision warning alarm, with audible warning and flashing LED's. When an alarm sounds the pilot must immediately look outside to see and avoid the traffic - perhaps after quick glance at the Flarm display to determine the direction of the threat. After you have flown with flarm for a season in the company of other flarm equipped gliders, this becomes second nature. b)Traffic data. Ie location, hight difference, climb rate and identity of flarm equipped gliders in the immediate vicinity. This is a new development which is now available to us with tools like XCSoar. The traffic data is suppressed if the flarm is put in "competition" mode. There are also two types of sentence transmitted by Flarm for "alarm" and "traffic" data. The traffic sentences are suspended if the workload on the Flarm unit is too high. They are not transmitted at all of the BAUD rate is below 19200. XCSoar Flarm radar, is only designed to convey "Traffic data". It is supplementary to the primary alarm interface. It is a mute point what to do with traffic that "disappears" due to a loss of Flarm traffic data. Perhaps it would be better to leave it lurking on the screen in the last known position for a delay period. The delay time could be inversely dependent on the last known distance to the target. (Ie close targets lurk longer after the signal is lost.) (Note I would NEVER rely on XCSoar, in its current form, as an interface to convey Flarm alarm data. Last I checked, XCSoar does not even read the alarm sentences. If you wanted alarm functionality on XCSoar, you would probably want a big red arrow appearing across the screen indicating the direction of the threat and nothing else on the display. I am not sure if I would even trust the Flarm/IOIO/Android platform for display of alarm data, as there are many process that could delay the "real time" display of alarms). Ian ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
