Is FLARM helpful?

At 12:26 24 November 2015, Ramy wrote:
... (With handful of Flarm saves in over 1000 hours with Flarm)

Interestingly, my experience is just the opposite: in 1593 hours in
the French Alps since 2007 (only 208 hours of which were without
Flarm), I have had no relevant alert from Flarm but hundreds of
false alarms. However I have experienced several dangerous or
very dangerous events (and many more daft ones) which can only
reasonably be ascribed to Flarm - or rather the false expectations
that some pilots seem to have of it.
The most stupid of these was two gliders simultaneously overtaking
me at speed from directly behind on a ridge, one each side, at
exactly my height, and with a horizontal separation of about a
wingspan. Fortunately, I had insisted that my pupil did *not* take
evasive action from the Flarm-announced threat, pointing out that
we might just turn into the path of the (imagined) single overtaker.
(I presume that the 2 overtakers thought "they know we're coming,
so they won't do anything stupid"!)
In the 2000+ hours in the Alps before Flarm I saw no such
dangerous behaviour; nor in the 208 hours 'gap' without Flarm in
2008.
Of course, nothing can be proved. But enthusiasts for Flarm should
be aware it has its down-sides.

On Tuesday, November 24, 2015 at 9:45:06 AM UTC-8, James Metcalfe wrote:
At 12:26 24 November 2015, Ramy wrote:
... (With handful of Flarm saves in over 1000 hours with Flarm)

Interestingly, my experience is just the opposite: in 1593 hours in
the French Alps since 2007 (only 208 hours of which were without
Flarm), I have had no relevant alert from Flarm but hundreds of
false alarms. However I have experienced several dangerous or
very dangerous events (and many more daft ones) which can only
reasonably be ascribed to Flarm - or rather the false expectations
that some pilots seem to have of it.
The most stupid of these was two gliders simultaneously overtaking
me at speed from directly behind on a ridge, one each side, at
exactly my height, and with a horizontal separation of about a
wingspan. Fortunately, I had insisted that my pupil did *not* take
evasive action from the Flarm-announced threat, pointing out that
we might just turn into the path of the (imagined) single overtaker.
(I presume that the 2 overtakers thought "they know we're coming,
so they won't do anything stupid"!)
In the 2000+ hours in the Alps before Flarm I saw no such
dangerous behaviour; nor in the 208 hours 'gap' without Flarm in
2008.
Of course, nothing can be proved. But enthusiasts for Flarm should
be aware it has its down-sides.

Really James, I suspect something is very wrong with your Flarm.

I have approximately 1000 hours with PowerFlarm and have not experienced any issues with false alarms. 6 camps and contests with as many as 65 gliders.

Richard
www.craggyaero.com

At 18:03 24 November 2015, Richard wrote:
... Really James, I suspect something is very wrong with your
Flarm. ...

Interesting thought. That would mean a fault in the Flarm
algorithms, or (highly improbable) a bad but operable installation of
the Flarm firmware. And, BTW, more than one Flarm unit was used
over those years.
J.

On Tuesday, November 24, 2015 at 11:16:35 AM UTC-8, James Metcalfe wrote:
At 18:03 24 November 2015, Richard wrote:
... Really James, I suspect something is very wrong with your
Flarm. ...

Interesting thought. That would mean a fault in the Flarm
algorithms, or (highly improbable) a bad but operable installation of
the Flarm firmware. And, BTW, more than one Flarm unit was used
over those years.
J.

Since you've owned several I guess it's safe to say there's more benefit than downside.

I'd be hard pressed to say I've ever had a false alarm - I guess it depends on how you define such a thing. If you mean an alarm when there were no other gliders in the air I would definitely look at whether you need to replace the hardware or firmware. If you mean you got an alarm for a glider in the area that you didn't think was an immediate threat you might consider 'competition mode' which sets the collision parameters tighter before issuing an alarm. We all have our comfort zone, but I'd be dubious about reports of alarms where that projected flight paths of the gliders involved weren't crossing within the radius of error that the algorithm assumes. As you may recall, Flarm projects curving flight paths, so you don't need to be on a straight-line converging path to generate an alarm. In a busy thermal you'll get lots of alarms, but the flying is so dynamic that the threats can come and go with regularity. It's not so much a false alarm in that case, but a transient conflict and probably not super-helpful, but technology has its limits in the analog world.

If the OP is considering whether to equip with Flarm I'd say if you intend to fly with other gliders, get one and if the other gliders don't all have them already, organize a group purchase.

I've had lots of useful alarms. I'd wager at least one prevented me from taking the silk elevator home.

9B

One thing to point out is that James is likely referring to the European Flarm while most of us referring to Powerflarm which I understand is superior especially in the user interface side (butterfly display etc) and as such I believe better visually distinguishing between alerts and collision alarm..

Ramy

Am Dienstag, 24. November 2015 23:59:45 UTC+1 schrieb Ramy:
One thing to point out is that James is likely referring to the European Flarm while most of us referring to Powerflarm which I understand is superior especially in the user interface side (butterfly display etc) and as such I believe better visually distinguishing between alerts and collision alarm.

Ramy

I have about 1600 hours flying with the European Flarm in the French and Swiss Alps, and I have had more than one occasion where the Flarm warning solved a very hairy situation. I also have had many false alarms, but I can live with that - I'd always take a false positive over a false negative.
On the technical side, I take good care that my antenna coverage is acceptable in any direction (which requires more than one antenna on a carbon fuselage).

Bert
Ventus cM TW

It is amazing what we pay for gas, insurance, tow fees and hanger fees, and also life insurance. What is a parachute, the real life insurance not life insurance that pays your heirs. So what Flarm, another form of real life insurance, that will keep you from using your parachute incase you have too. Not to mention if you have had a collision with a sailplane or larger ship you will most likely be in bad shape. Yes I know chutes may need to be used with a collision. So to me, Flarm is just another form of real life saving insurance, that is pretty inexpensive for what it had and can do.

On the technical side, I take good care that my antenna coverage is acceptable in any direction (which requires more than one antenna on a carbon fuselage).

Bert
Ventus cM TW

Bert,
Could you tell us where you place your multiple antennas on your carbon fuselage, and the type of antennas you are using.
Thanks,
Mark

At 22:59 24 November 2015, Ramy wrote:
One thing to point out is that James is likely referring to the
European
Flarm while most of us referring to Powerflarm which I
understand is
superior especially in the user interface side (butterfly display
etc) and as such
I believe better visually distinguishing between alerts and collision
alarm
Ramy

Indeed, I have not come across a Powerflarm unit, and don't know
what the differences are. But I don't feel that there is any
ambiguity in 'European' Flarm indications.
J.

Flarm just announced a new external antenna recommended for carbon and metal planes (Flarm and Powerflarm frequencies).