Flarm Target direction

The rule of thumb is that if you can’t quickly locate the other aircraft and not sure what to do, it is better to do something than nothing since the collision algorithm detected that if both gliders will continue in their predicted pass they may collide. As such, if you change your path you will reduce the risk of collision. And it is faster to push the nose down or pull the nose up and quickly change altitude, then initiate a bank. Bank away (normally to the right) if you see the target and determine you have enough time to maneuver.

Ramy


On Wednesday, June 2, 2021 at 12:57:15 PM UTC-7, wrote:
On Wednesday, 2 June 2021 at 00:22:39 UTC+12, Dan Daly wrote:
On Tuesday, June 1, 2021 at 1:15:57 AM UTC-4, wrote:
Earlier in the year I had a close call, the Flarm was going off with multiple targets most of which I could visually identify. One I did not see, we both had to turn sharply left to avoid a straight on collision.
Apparently Flarm calculates the potential collision taking into account all directions of movement including turn radius. If I had the Flarm view on the S100 set to the correct zoom I most likely would have picked up the circling glider heading my way. Same possibly goes for the other glider.
Accepting the Flarm view may have shown the exact position of the target, when it switches to the warning mode is it still pointing to the target or the potential collision point?
To clarify I was flying straight and level the target was in a thermal, probably banked 30deg turning left.
Cheers
Anton L
I can't speak to the FLARMview (you might try reading the manual), but from the Butterfly Display, it says in "Traffic Warnings":
"The warning-screen shows the viewing angle to the most dangerous collision threat. A
compass-style indicator gives information about the horizontal viewing angle to the threat."

In addition, the FTD-012 Interface Control Document (version 7.12, July 2019), page 20, speaking on PFLAA sentence (data on other proximate aircraft), says it delivers " Relative position in meters true north from own position... Relative position in meters true east from own position... Relative vertical separation in meters above own position. Negative values indicate that the other aircraft is lower.")

So, it points to where the threat currently is, which makes sense, because it gives a direction for you to look in. If it pointed to where the threat will be, there will be nothing there.

I am interested why you both turned left. I was taught that aircraft approaching head-on both were required to alter course to the right. Perhaps it's different where you fly.
Yes in retrospect it's obvious that it points to the target not the collision point, what slightly complicated the situation was the opposing glider was circling to the left and I was going straight, hence the initial question of where does the warning point.
The fact the opposing glider was already in a left hand turn is why he went more left and I left the opposite way.
Unlike TCAS, Flarm doesn't tell you how to avoid the collision, that is left to the pilot to decide, if you haven't sighted the opposing aircraft its hard to know what to do, that was my dilemma. In future I'll get out of there if I have any doubt.

The FlarmLED offers minimal information. With other displays you can adjust the range to allow yourself to see what other aircraft are up to as well as relative altitude, azimuth, range, vario, FlarmNet ID...

You can use that information to keep clear (or leech) and generally avoid alarms.

Flight computers connected to a Flarm can also show Flarm targets and give audible and visual notifications well ahead of time.

I was the other pilot in this near miss. Just to give more context it was a pre-start in a competition day, there were a significant number of sailplanes in this thermal, a number of which were at or about my altitude, not to far under cloud-base in rather murky shady visibility.
In this situation where Anton was approaching a thermal with many sailplanes Flarm is of limited use. Yes it will warn of predicted collision danger which should be heeded, but that is an adjunct to "Mark 1 eyeball". Anton and I saw each-other at the same time and he did everything right from that point and the situation was sorted.
I think it is one of those situations which will statistically arise from time to time and it is training and airmanship which will save the day, not the reliance on Flarm.

Further to the continued need for old fashioned "mark one eyeball" is recognition that Flarm does not work in all geometrical situations.
I was an unwitting participant in a comp near miss where 2 gliders (both with correctly configured, non stealth set Flarms) failed to detect an imminent collision with the two gliders approaching each other 45 degrees off of head on and one slightly higher than the other. It was over in a matter of seconds, and fortunately we saw each other at the last moment, he pulled and I pushed, and he passed close over me. Neither of our Flarms gave any warning. In our talk about it afterwards we theorized that the carbon underbelly of the higher glider blocked the transmissions between the two Flarm antennas (both of which were mounted on our glare shields). Both Flarms continued to work properly throughout the competition.
ROY

Roy,

Even with carbon blocking there should have been an alarm. The carbon reduces range but should not completely block. If this was the reason this is a strong case for installing B antenna in the belly. It would have been worthwhile to send both igc files from each powerflarm to flarm team to analyze, as it includes log data for all other flarms it receives. It could be a flarm display configuration issue. Unfortunately there is no standard nor best practice as of how to configure your display effectively. Every one configures differently, and some just keep factory defaults which are often wrong. I have both my old butterfly display and my LX9000 and the butterfly display provides more warnings than my LX9000. It should be fixed in the next LX Firmware release.

Ramy

On Thursday, June 3, 2021 at 9:54:58 AM UTC-7, Roy B. wrote:
Further to the continued need for old fashioned "mark one eyeball" is recognition that Flarm does not work in all geometrical situations.
I was an unwitting participant in a comp near miss where 2 gliders (both with correctly configured, non stealth set Flarms) failed to detect an imminent collision with the two gliders approaching each other 45 degrees off of head on and one slightly higher than the other. It was over in a matter of seconds, and fortunately we saw each other at the last moment, he pulled and I pushed, and he passed close over me. Neither of our Flarms gave any warning. In our talk about it afterwards we theorized that the carbon underbelly of the higher glider blocked the transmissions between the two Flarm antennas (both of which were mounted on our glare shields). Both Flarms continued to work properly throughout the competition.
ROY

Ramy:
I don't profess expertise in this area, but note that in addition to the carbon underbelly there is a lot of hardware under the glare shield mounted Flarm antenna that can block downward/forward transmission: canopy hinge mechanisms, rudder pedals & adjuster, instruments, flasks, computers, and even the metal Flarm Core box itself.

Again, I not knocking Flarm - it's a useful tool. But I don't depend on it to avoid you guys . . .
ROY

I mount two long antennas on opposite sides of my canopy. Use a block with Velcro to keep the antenna tips clear of the canopy. Having transmit on both antennas as with Fusion is even better.

Unfortunately Flarm advertised dual transmit with the Core 1.1, but omitted to obtain approvals for North America.

For a new glider I'd spec Flarm and transponder antennas in the fin, perhaps with an access panel, and the secondary Flarm Antenna on a canopy side to cover the blind spot overhead the tailplane.

On Friday, 4 June 2021 at 00:43:09 UTC+12, Brett wrote:
I was the other pilot in this near miss. Just to give more context it
was a pre-start in a competition day, there were a significant number of
sailplanes in this thermal, a number of which were at or about my
altitude, not to far under cloud-base in rather murky shady visibility.
In this situation where Anton was approaching a thermal with many
sailplanes Flarm is of limited use. Yes it will warn of predicted
collision danger which should be heeded, but that is an adjunct to "Mark
1 eyeball". Anton and I saw each-other at the same time and he did
everything right from that point and the situation was sorted.
I think it is one of those situations which will statistically arise
from time to time and it is training and airmanship which will save the
day, not the reliance on Flarm.




--
Brett
Cheers Brett,
Writing an article for the news letter on it so just getting a few ducks in a row, will send it to you for review before it goes out.
Anton

Just my two cents here but we...the aviation community...should not be test pilots for an aviation safety device.
I feel the manufacturer (FLARM) should have done research on things like antenna placements, especially antenna placements on particular aircraft, to determine what the best solution is.
The quality of the operation of every FLARM unit is essentially a test rig without any quality control or standardization.
The current pool of test pilots has a technological compentency range of top flight electrical engineer to barely able to operate a toaster.

Perhaps organizations, like FAI or SSA or AOPA should step up to the plate and start a controlled process for determining installation guidance for individual planes?
My personal experiences have been frustrating.
Just one example...there are several carbon gliders that I can fly below and behind that never see me on their FLARMS.

I could not feed Flarm information to both the Butterfly Vario and the LX 9070. Flarm kept losing the configure. Richard disconnected my Butterfly from the Flarm and problem solved. I am wondering how I could you have both Butterfly and LX operational with Flarm at the same time? Thanks in advance.

On Thursday, June 3, 2021 at 10:10:25 AM UTC-7, Ramy wrote:
Roy,

Even with carbon blocking there should have been an alarm. The carbon reduces range but should not completely block. If this was the reason this is a strong case for installing B antenna in the belly. It would have been worthwhile to send both igc files from each powerflarm to flarm team to analyze, as it includes log data for all other flarms it receives. It could be a flarm display configuration issue. Unfortunately there is no standard nor best practice as of how to configure your display effectively. Every one configures differently, and some just keep factory defaults which are often wrong. I have both my old butterfly display and my LX9000 and the butterfly display provides more warnings than my LX9000. It should be fixed in the next LX Firmware release.

Ramy
On Thursday, June 3, 2021 at 9:54:58 AM UTC-7, Roy B. wrote:
Further to the continued need for old fashioned "mark one eyeball" is recognition that Flarm does not work in all geometrical situations.
I was an unwitting participant in a comp near miss where 2 gliders (both with correctly configured, non stealth set Flarms) failed to detect an imminent collision with the two gliders approaching each other 45 degrees off of head on and one slightly higher than the other. It was over in a matter of seconds, and fortunately we saw each other at the last moment, he pulled and I pushed, and he passed close over me. Neither of our Flarms gave any warning. In our talk about it afterwards we theorized that the carbon underbelly of the higher glider blocked the transmissions between the two Flarm antennas (both of which were mounted on our glare shields). Both Flarms continued to work properly throughout the competition.
ROY