FLARM
Presentation plan An Alert to see and avoid potential collisions Why do we need it? Understand how it works Concentrate on lookout React to the alert tone Etiquette - Fly so as not to give alerts
FLARM FLARM is a hardware and software system developed by the Swiss company Flarm Technology GmbH. This company has licensed the use of the software to various glider instrument manufacturers for inclusion in their equipment. Several private gliders and all the DSGC fleet are fitted with units manufactured by LXNAV, and this presentation is based on these units.
Why do we need it?
The motivation in 2001 20 GA mid-air events per year world-wide In every 3rd event gliders were involved 50% fatality rate Every 3rd fatality in gliding caused by mid-airs Many more near-misses than mid-airs Many near-misses remain unnoticed
BGA accident stats. Between 1974 and 2014 there were 85 collisions involving 38 deaths In 2014 there were 4 collisions involving 10 crew, there were no deaths
The risk magnifiers Distraction and / or poor lookout Blind spots In or joining thermals At cloud base in poor visibility (cloud streets) On ridges Flying into the sun In the circuit XC flying with colleagues In contests Poor acquisition against background
Busy airspace
Where s the threat?
Speed 60 kts 80 kts 100kts Closing speed is twice this! Distance Time to collision metres seconds 2000 30 23 18 900 14 10 8 700 11 8 6 Wingspan = thumb width at arm s length 400 6 5 4 Fuselage diameter same as yaw string 200 3 2.3 1.8 kkkk Real-time closing size and speed (in reality, gliders are not black) 100 1.5 1.1 0.9 50 0.75 0.56 0.45 20 0.3 0.23 0.18 10 0.15 0.11 0.09 10
FLARM is: A system to alert a pilot to see and avoid - Warning mode A system to aid situational awareness - Nearest mode Hardware which has: - a primary acoustic alert - a secondary visual display
What FLARM does: Flarm predicts its flight path up to thirty seconds ahead Flarm updates and then broadcasts its predicted flight path every second Flarm analyses other transmitted flight paths Flarm gives increasing intensity of alerts at 18, 13 and 8 seconds from the intersection of predicted flight paths
What it does not do: Flarm can not predict what the pilot is going to do Flarm is not a proximity warning device Flarm does not tell the pilot what to do, to avoid a collision
Hardware A GPS receiver (GPS altitude) A low power radio transceiver to broadcast and receive flight-path predictions A simple user interface and alert display Options SD card for updates, configuration and logging IGC approved flight recorder NMEA data output Voice alert unit
Hardware Manufactured by in Slovenia others are available
User interface (1) Status : 3 greens Horizontal Direction: Clockface Vertical direction: Height Bar
User interface (2) NEAREST mode Yellow steady LEDs No audio
User interface (3) WARNING mode Horizontal Direction Clockface Beeping audio Red flashing LEDs (NB: The audio alert is far more important)
User interface (4) WARNING mode Vertical Direction Height bar Beeping audio Red flashing LEDs (NB: The audio alert is far more important)
Operating modes Warning Mode: will show flashing red LEDs and sound a beep if a collision is predicted Nearest Mode: will show steady yellow LEDs (and no sound). Will change over automatically to Warning Mode if a collision is predicted
Settings Push button Cycle thru volume Toggle Mode Please do not change settings on Club Gliders (Loudest, Nearest)
What s the button for? Short press (<0.8 s) will cycle through three different beep volumes. Long press (>2 s) toggles the mode between Nearest and Warning Long press, on power up, will put the unit into setup mode. Please do not change settings on Club Gliders (Loudest, Nearest)
Daily Inspection etc Check Flarm aerial is vertical Fit glider battery Turn on Master switch Allow Flarm to complete its setup (it may take ~2 minutes) At end of day, turn off master switch......and remove battery as normal Please do not change settings on Club Gliders (Loudest, Nearest)
System algorithm Not a simple proximity alarm Transmits 3D path predictions based on the probability of being within a certain bit of air for each second up to 30 seconds ahead Glider's energy and flight mode considered Recalculated and retransmitted every second Compares path predictions for your glider and others Gives an alert to possible collision when paths conflict in time and space Range about 2 km depending on aerial installation
Alert timings Initial level of alert begins at 18 seconds. Slow beep and flashing red LED Next level of alert at 13 seconds. Faster beep and faster flashing red LED Highest level of alert at 8 seconds Fastest beep and fastest flashing red LED (These timings are always the same, but some other Flarm units have more flashing red LEDs as the level increases)
Flight Path Predictions Lateral Separation No intersection of predicted flight path = No Warning Alert Both Red and Black see: Nearest mode
Flight Path Predictions Near head-on Intersection of predicted flight path = 18 second Alert Both Red and Black see:
Flight Path Predictions Flying in echelon No intersection of predicted flight path = No Warning Alert
Flight Path Predictions Turn without looking Intersection of prediction circles = 8 second Alert Red sees: Beep 6hz Black sees: Beep 6hz
Flight Path Predictions Near-by circling No intersection of prediction circles = No Warning Alert
Flight Path Predictions Opposing circling Intersection of prediction circles = 8 second Alert Red sees: Beep 6Hz Black sees: Beep 6Hz
Flight Path Predictions Opposing circling 2 Intersection of prediction circles = 8 second Alert Red sees: Beep 6Hz Black sees: Beep 6Hz
Flight Path Predictions Concentric circling No intersection of prediction circles = No Warning Alert
Flight Path Predictions Track v Heading (1) 50 30 50 R I D G E Intersection of prediction flight path = 18 second Alert Red sees: Black sees:
Flight Path Predictions Track v Heading (2) 50 30 50 W A V E B A R Intersection of prediction flight path = 18 second Alert Red sees: Black sees:
Flight Path Predictions Threat from the Rear Intersection of prediction circles = 18 second Alert Red sees: 40 Black sees: 60
Alerts in a thermal There may be frequent alerts in a busy thermal due to close formations Flarm is quite good at prediction conflicts in thermals, but lookout is more important especially if some don t have Flarms Try to fly nicely, so as not to give alerts (Flarm Etiquette)
Alerts in the cruise The alert is to the closest conflict in time Don't Panic!!! there is usually plenty of time First look out and forward (The hardest impact will always be from head-on) Scan quickly If you can t see a conflict, then glance at the display Possibility of a track / heading difference (Look more downwind) Usually a small correction of path is sufficient If the alert is from a glider behind you then you are in front of it and may be visible to its pilot
Flarm in action http://www.youtube.com/watch?feature=pla yer_embedded&v=zulmcztscm4&autoplay =0
Flarm in action (2)
To summarise An Alert to see and avoid Concentrate on lookout React to the alert tone Fly so as not to give alerts Remember not all are Flarm equipped And finally...
Reminder DO NOT experiment by flying at other FLARM equipped gliders!