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#1
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PowerFlarm and transponders while towing?
While aero-towing a Mode-C transponder equipped glider, and using
PowerFlarm and transponder in the tow plane, most of the time the glider will show up on the PF as a threat aircraft. Since the PF prioritizes threats, this precludes another more distant "intruder" aircraft as being displayed as a threat. I'm not entirely sure how PF really deals with this, but it did prompt the idea of turning the glider's transponder to standby during the tow. And how best to accomplish this while minimizing the risk of the glider pilot forgetting to switch the transponder back to ALT after release? It’s accepted practice to turn off all but one transponder when formation flying with power aircraft. This to prevent each transponder from replying to ATC or TCAS at the same time and each stepping on the other so the receive end gets interference. This probably has not been much of a problem with a tow plane and glider because traditionally few tow planes have had transponders. At Minden, NV, near a busy terminal area and near approach paths into Reno, all of the tow planes have transponders, and most of the gliders do as well. Yet we have not adopted a policy of leaving the glider transponder in standby mode until tow release so as to prevent the multiple transponder proximity conflict. Perhaps a change in our normal tug to glider “radio check” prior to launch: Tug says “transponder on standby” to glider prior to launch, glider responds, “on standby”. At tow release, glider uses the term, “transponder on” instead of the “off tow” or “thanks for the tow” used currently. If glider does not use that phraseology, tow plane responds, “check transponder on”. Comments and suggestions . . . bumper zz Minden, NV |
#2
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PowerFlarm and transponders while towing?
On Feb 21, 9:14*am, Tim Newport-Peace ] wrote:
Not sure about PowerFlarm, but on EU Flarm the is an option to suppress visual and audible warnings, but still Tx data. Are you operating in 'Nearest' or 'Collision' mode? Perhaps the answer is RTFM No, PowerFlarm doesn't have a "collision" mode that is manually switched. It does use logic to suppress non-collision likely gliders that are sharing a thermal, but this is an automatic function. Also, we are not yet dealing with PowerFlarm vs. PowerFlarm, and I've only done ground tests with two portable units on a collision course in golf carts :c) as in the US we are just starting to equip and there are very few airborne PF's, except at contests. My use of PF so far, is using only the PCAS functions (where the PF displays only range and altitude of a Mode-C equipped threat aircraft). BTW, I did RTFM . . . several times, honest. bumper |
#3
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PowerFlarm and transponders while towing?
If the PowerFlarm had an option to surpress 1202 transponder codes in
the US that might help. You eliminate the false alarms from gliders with the hope that those same gliders adopt powerflarm. Knowing the adoption rate of PowerFlarm at your gliderport of those gliders with transponders would allow an informed/calculated decision which would eliminate false alarms and therefore preserve the value of the PCAS warnings. On Feb 21, 11:38*am, bumper wrote: On Feb 21, 9:14*am, Tim Newport-Peace ] wrote: Not sure about PowerFlarm, but on EU Flarm the is an option to suppress visual and audible warnings, but still Tx data. Are you operating in 'Nearest' or 'Collision' mode? Perhaps the answer is RTFM No, PowerFlarm doesn't have a "collision" mode that is manually switched. It does use logic to suppress non-collision likely gliders that are sharing a thermal, but this is an automatic function. Also, we are not yet dealing with PowerFlarm vs. PowerFlarm, and I've only done ground tests with two portable units on a collision course in golf carts :c) as in the US we are just starting to equip and there are very few airborne PF's, except at contests. My use of PF so far, is using only the PCAS functions (where the PF displays only range and altitude of a Mode-C equipped threat aircraft). BTW, I did RTFM . . . several times, honest. bumper |
#4
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PowerFlarm and transponders while towing?
I suggest a second sticker on the vario.
My first sticker says “gear”. I stick it on the vario when launching. If it still there when I come off tow and start thermalling etc., it impedes my view of the vario and reminds me to raise the undercarriage. When I have done the latter, I move the sticker to the airbrake/spoiler handle. If it is still there when I approach for landing, I have forgotten to lower the gear. When I do lower the gear, I move the sticker back to the vario as I don’t need it for approach and landing. For the USA transponder/PowerFlarm, I would have a second sticker on the vario saying transponder/PowerFlarm. If still there when looking for lift, it would mean I forgot to switch them on after pulling off tow. Cheap, fairly foolproof, and the only time it let me down (or rather I goofed) was when I forgot to put the sticker on the vario in the first place, and ended up landing without lowering the gear. Chris N. |
#5
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PowerFlarm and transponders while towing?
But, but, but... A glider on tow is not on a collision course with the tug.
So why is PowerFlar alerting on the glider trailing behind? Why wouldn't it alwo alert on a glider behind you in a thermal? I'm still not convinced... "Chris Nicholas" wrote in message ... I suggest a second sticker on the vario. My first sticker says “gear”. I stick it on the vario when launching. If it still there when I come off tow and start thermalling etc., it impedes my view of the vario and reminds me to raise the undercarriage. When I have done the latter, I move the sticker to the airbrake/spoiler handle. If it is still there when I approach for landing, I have forgotten to lower the gear. When I do lower the gear, I move the sticker back to the vario as I don’t need it for approach and landing. For the USA transponder/PowerFlarm, I would have a second sticker on the vario saying transponder/PowerFlarm. If still there when looking for lift, it would mean I forgot to switch them on after pulling off tow. Cheap, fairly foolproof, and the only time it let me down (or rather I goofed) was when I forgot to put the sticker on the vario in the first place, and ended up landing without lowering the gear. Chris N. |
#6
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PowerFlarm and transponders while towing?
On Feb 21, 4:19*pm, "Dan Marotta" wrote:
But, but, but... *A glider on tow is not on a collision course with the tug. So why is PowerFlar alerting on the glider trailing behind? *Why wouldn't it alwo alert on a glider behind you in a thermal? I'm still not convinced... "Chris Nicholas" wrote in message ... I suggest a second sticker on the vario. My first sticker says “gear”. I stick it on the vario when launching. If it still there when I come off tow and start thermalling etc., it impedes my view of the vario and reminds me to raise the undercarriage. When I have done the latter, I move the sticker to the airbrake/spoiler handle. If it is still there when I approach for landing, I have forgotten to lower the gear. When I do lower the gear, I move the sticker back to the vario as I don’t need it for approach and landing. For the USA transponder/PowerFlarm, I would have a second sticker on the vario saying transponder/PowerFlarm. If still there when looking for lift, it would mean I forgot to switch them on after pulling off tow. Cheap, fairly foolproof, and the only time it let me down (or rather I goofed) was when I forgot to put the sticker on the vario in the first place, and ended up landing without lowering the gear. Chris N. To clarify, Bumper is only talking about the mode C alert, NOT flarm alert. Mode C only alerts you of the nearest transponder equipped aircraft (the glider in this case), not of a collision alert. Would have been great if it was capable of displaying more than one threat, than there wouldn't be an issue. Ramy |
#7
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PowerFlarm and transponders while towing?
As Ramy says. Also, if both have PowerFlarm and Transponder, the
glider PF will only show the tug transponder as the nearest and will not alert to a possible approaching transponder. As the combination is one entity in air law (I assume it is in the USA as it is in the UK) it is logical to leave all unambiguous alerts to the tug pilot. Once separated, the glider needs its own alerts, and the tug will soon be away. (Because I have separate PCAS and Flarm in my glider, and no transponder, I don’t have the problem.) Not that you can’t still have collisions – I know of at least one UK fatal collision between a tug and the glider it had not long since towed up. Be careful out there. Chris N. |
#8
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PowerFlarm and transponders while towing?
A possible solution would be to have the PF ignore a constant close-
in, almost same altitude threat (i.e.the glider) after a reasonable period of time, say a couple of minutes. After staging, this would have the tow plane PF start to ignore the glider's Mode-C either on the take off roll or early in the climb. Additionally a software fix might be tied in to the aircraft type and function only if the "tow plane" option is menu selected. I've contacted PowerFlarmUS re. this and some other suggestions and they are responsive. I wasn't meaning to do an end run, but rather wanted input from others to confirm if what I'm experiencing is indeed a problem needing addressing. The seperate issue of tug and glider transponders interfering with one another while on tow has no fix, I'm aware of, other than leaving one transponder in standby for the duration of the tow. bumper |
#9
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PowerFlarm and transponders while towing?
At SoaringNV's staff meeting yesterday, we discussed the PowerFlarm
and transponder issue. It was quickly decided that having the glider transponder on STBY until release would not be workable due to the fact we often have non-pilots sitting behind the main instrument panel. So, yesterday we tried having the tow plane squawk standby until tow release, then switch to ALT. This works fine in terms of not having the transponders interfere with each other . . . but does nothing to resolve the PF beng in constant alarm due to the collision it thinks might occur at any time between tug and glider. But, this thread brought elicited a private response reminding me what I already knew, and that is that the FARs require a transponder be on at all times if its installed, except as directed by ATC etc. ATC will almost always direct that all but the "lead" aircraft squawk standby when formation flying, something that we do often while towing. To try and resolve this I called Reno Approach who quickly shuffled me off to NorCal Approach. Talked with a front line manager there who advised us to do exactly what I suggested. i.e. Leave the tug transponder squawking STBY until tow release and then don't forget to switch to ALT. Now he did say that even if we left both on ALT, they would probably still be able to see us*. But then added that the data displayed would be confused and would potentially cause conflict alarms as well. *A secondary concern is that TCAS equipped aircraft will get good data from our transponder/s. bumper zz Minden |
#10
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PowerFlarm and transponders while towing?
Not to sound like a smartass, but have you considered leaving the PowerFlarm
off until release? Is the collision potential so great over your usual tow route/altitude that you don't feel safe without it? "bumper" wrote in message ... At SoaringNV's staff meeting yesterday, we discussed the PowerFlarm and transponder issue. It was quickly decided that having the glider transponder on STBY until release would not be workable due to the fact we often have non-pilots sitting behind the main instrument panel. So, yesterday we tried having the tow plane squawk standby until tow release, then switch to ALT. This works fine in terms of not having the transponders interfere with each other . . . but does nothing to resolve the PF beng in constant alarm due to the collision it thinks might occur at any time between tug and glider. But, this thread brought elicited a private response reminding me what I already knew, and that is that the FARs require a transponder be on at all times if its installed, except as directed by ATC etc. ATC will almost always direct that all but the "lead" aircraft squawk standby when formation flying, something that we do often while towing. To try and resolve this I called Reno Approach who quickly shuffled me off to NorCal Approach. Talked with a front line manager there who advised us to do exactly what I suggested. i.e. Leave the tug transponder squawking STBY until tow release and then don't forget to switch to ALT. Now he did say that even if we left both on ALT, they would probably still be able to see us*. But then added that the data displayed would be confused and would potentially cause conflict alarms as well. *A secondary concern is that TCAS equipped aircraft will get good data from our transponder/s. bumper zz Minden |
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