Do military planes see GS aircraft that are using SafeSky?

My main interest in SafeSky is to be seen by other aircraft, not seeing them on screen (although that can obviously be useful and fun). I fly a hot-air balloon, meaning I am almost static in the sky (airspeed zero, groundspeed and course equal to windspeed/course). Thus, apart from descending or climbing, unable to do evasive manoeuvers even if I see other aircraft (and in an open basket I spend 90 percent of my time looking around me). Others must see me to allow me right of way and avoid me. Most GA planes have litte trouble there unless they are coming around a hill that I am behind and thus invisible for the naked eye; in the open a hot-air balloon is large and brightly coloured so easily spotted. The main problem is military flights in G airspace where they may fly low and relatively fast. They can be anywhere, and if a military training area is nearby, even inactive, that tends to increase the chance of them being in my area. I’ve had military aircraft passing at speed at less than a km and same altitude in situations where all parties involved had the right to be there. Obviously I cannot avoid a fighter plane coming at me at more than 500 km/h, and recently here in France we got ‘transfer corridors’ in many areas that remain G uncontrolled but allow MIL flights below 500 ft AGL (typically flying at 250-300 ft AGL), in theory to stay below GA aircraft that must remain above 500 ft AGL. But non powered aircraft like gliders and balloons are allowed below 500 ft, so there can be conflict.
Transponders and other complex transmitting gear are very difficult to install in a balloon, even impossible in smaller baskets.
Hence I want to try SafeSky to transmit that I am there, through its servers, and want to know if MIL flights and MIL ATC can see aircraft that have SafeSky activated (or more to the point, in my case, where the pilot has his android phone in his pocket with SafeSky running).
Anyone have any info on that ?

I know that it costs money, but have you considered a small, portable, Mode S transponder? I have a Trig TT21 with small battery pack (in my vintage aircraft) and get around 6 hours of use before battery needs charging.
If you have one of those in your balloon then you will be very visible to ATC radar, and probably most mil aircraft. Also get a GPS connected to the TT21 to provide ADS-B OUT and you will then be visible to almost everything.

Hello @Schwep,

There are rumours that MIL ATC are looking at crowed-source websites to see what they cannot see any other ways :slight_smile: But that will never be officially confirmed.

That said, if it’s not for MIL traffic, there area a lot of fast ultra-light aircrafts such as VL3 or MCR and other fast motorplanes that will also not be avoidable. It’s becoming common to fly > 200km/h. So in general, being seen by simple and affordable means do matter.

I can only recommend to add to your check list to start SafeSky for all your flights. It’s free, and you will be seen by a community of 60 000 pilots in Europe. And “maybe” by MIL ATC too…

And this is not mutually exclusive to using an electronic device too as recommended by @tnowak

Fly Safe,


Hi, I looked at the Trig, they do sell them in combo boxes with battery etc. to make them portable, in a cordura or leather case. That is OK if you fly a big 16-person commercial balloon with a large separate pilot compartment and you are often near or even in controlled airspace (busy tourist areas also tend to be in areas with airfields). In that case, you have no choice - a mode S transponder is mandatory for commercial passenger transport if ATC asks you to carry it (and in some countries it’s mandatory in most of the airspace, even in G space, such as in the Netherlands and Belgium; but not in France as yet). Problem is, I have a basket of 110 x 100 cm that carries three people, three fuel tanks, first aid kit, fire blanket, long handling rope, fire extinguisher etc, pilot harness, and my pilot gear bag. EASA has made more and more stuff mandatory and it all takes up space. Even the Trig is a pretty marge case with a big Lithium battery in it, angular, and there is no room left for it unless I take only one passenger instead of two. Plus, even in that case, the Trig would not be where I am in the basket so essentially out of my reach. I have my instruments (small, hang glider style) and handheld radio strapped to the support poles of the burner frame, so above the basket . No place left. Plus, if my info is correct, as the balloon does not reflect radar, it also needs a physical reflector hanging outside/under the basket (which then must be pulled up into the basket for landing, not practical). A SkyEcho might be a solution as it’s small and if in a suitable soft case, could be strapped to a burner frame pole above my radio, say. But that is not what EASA wants at this time… I guess that may change.
The other point is, I normally fly in G airspace far from airfields, uncontrolled up to FL 85. There is no obligation to carry a transponder here, so I don’t want the hassle and the cost of one but I’d like to be visible to people who look a lot at screens and not outside. In good VFR weather I am very visible to the naked eye.
Do note that in a ballon there is no question of linking a transponder, SkyEcho, SafeSky etc. to another built-in device as we don’t have instrument panels like in fixed wing aircraft. Again, in big balloons some pilots mount portable Garmins designed for aircraft, with moving ICAO maps etc. - and then are distracted by the screen all the time. Since the introduction of tablets with moving maps we have seen more collisions with power lines as people were looking less outside. I don’t want electronics to distract me when I fly at 200 feet AGL (which is legal for us btw). If most other users can see me on screen when I have activated SafeSky on my phone, that certainly helps in cases like the fast ultralights.

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Just to be clear, even if I were using an electronic device that allows me to see others, I cannot act on that. Balloons have no propulsion, no rudder and we are almost static (GND speed usually less than 20 knots, and at low height AGL, way less than that). I can only climb and descend with a fairly long reaction time. That is why everybody else is supposed to give me right of way by air law. Motorized gives way to non motorized and steerable gives way to non steerable. I’m a non-moving obstacle, practically. Add the practical problems for carrying a classic transponder in a small balloon and I can only hope that being the size of a Boeing and brightly coloured will be sufficient… lol.

Dear Frank,

Thanks for your reply.

I understand your concerns/limitations.

Could the Trig transponder equipment be strapped to the outside of your basket somewhere?

I use a SkyEcho 2 for ADS-B OUT and FLARM reception and it works very well with my EFB (SkyDemon).

I run SkyDemon on my Samsung S22+ smartphone.

I fly a vintage Piper aircraft with no proper electrical system; just one 6 AH rechargeable battery which powers my Trig TY91 radio and TT21 transponder.

For now, as there are so many different applications one could use to improve EC, regarding military aircraft and fast GA (Pilatus PC x/Cirrus etc) then it is unlikely they would be carrying any non-certified equipment for detection purposes.

I really only use SkyDemon (SD) for navigation purposes and I have the conflict alert audio connected to my radio. So I get audio alerts through my headset.

I never look at the SD screen close to airfields, unless I get a conflict alert. Mark 1 eyeball is then used, but that also has limitations!

A SkyEcho 2 may be your solution, along with phone-based apps like SafeSky.


Tony Nowak


Hi Tony,

Attaching a transponder or anything else valuable and fragile on the outside of a basket is not a good idea. Balloons don’t typically land nice and soft on a flat surface, we land in rural fields, small clearings, often with rough ground and in most cases the basket will end falling on its side. The basket may hit bush and even barbed wire if things get rough. Not to mention mud and cow pats! I don’t think a transponder in a case outside would survive long. I already keep the balloon bag outside on what would normally be the ‘rear’ of the basket during a landing approach so it won’t snag if the basket hits something with branches. For the same reason a suspended reflector would be unpractical. Plus, a mode S transponder will allow ATC to see me but if I understand properly, I would still not show up on the screens of nearby aircraft like UL/L/Mil, so it woud not make me safer. A SkyEcho looks like the most useful option as these things are small and independent and don’t need ATC to tell others I am in the area.
As things stand now, including budget restraints, just taking care not to fly in anything but real VFR conditions (as in way better than the minimum 1500 m in G space) and being very blue and larger than most airliners is still the best way as long as others use their Mk1 eyeballs; with SafeSky running on my phone this season.
Ballooning is a wholy different world than anything with wings and rudder. I often talk to cattle when I fly… lol.
Photo strip of balloon landing

Dear Frank,

It looks like you have a unique situation regarding your balloon.

I suggest you check with uAvionix regarding the SkyEcho 2 to confirm if regular ATC radar units and military aircraft would see your ADS-B Out transmission.

The unit only sends out a fixed squawk code, usually 7000, plus your GPS derived position.

I know nothing about ballooning but are you trying to fix a problem that doesn’t or rarely exists?

If you are trying to avoid fast mil jets from coming close, then surely even they are using Mk1 eyeball? As you say, your balloon will be visible from miles away.

Regarding making your balloon more visible to ground based radar units, is there any way to line your basket with radar reflecting material, such as thin aluminium foil, sheet, or similar?

I would have thought a few m2 of aluminium would make you a lot more visible to primary radar?



Balloons are indeed unique. We don’t fly, we drift. Lol. Crazy stuff, grabbing the sky in a wicker basket under a large bag of nothing but air. I’ll check with uAvionix regarding the SkyEcho and I’ll bring this up in an upcoming audit of my ‘declared commercial transport activity’ by a team of civil aviation inspectors… lol, snif.
Squawk code 7000 VFR is what we would be using anyway. GPS position is fine.
Um, the problem is real. One, my area can be activited as a mil training area for extremely low, extremely fast flights (lower limit GND), in which case it is off limits for anything civilian. Then, obviously I don’t fly. It is also, since last year, a ‘transit zone’ for fighter planes flying under 500 ft AGL, typically between 250 and 500 AGL, every weekday from 0800 local to the end of the afternoon. The space then remains G uncontrolled and permeable for non-motorized civil aircraft that are normally authorized below 500 ft AGL (gliders, parasails, hang gliders, balloons…) The brilliant idea seems to be that low flying fighters can pass under normal motorized GA aircraft and thus theoretically prevent collisions. Ahem. I guess a Mirage or Rafale hitting a hang glider or balloon will just continue on while the soft structure of the civilian craft crashes.
Our area is hilly so if I fly below 500 ft AGL to navigate and approach for landing, I may not be visible even to a military Mk 1 eyeball of a fighter pilot who is coming around a hill or passing low over it doing terrain following on autopilot. That is a real risk. I have already been passed at some 500 meters by a patrol of fighters going 400 knots, at around 500 ft AGL. That was before the new transit zone was introduced, so I could descend (theoretically) to a height that would allow me to remain under them (not that I could do anything useful once they are close enough to see them, at such speeds). If they pass at 75 metres over GND, it gets hairy if my basket is just above the treetops, the crown of the balloon then being at some 50 meters over GND.

Obvious solution would be to fly evenings, not mornings, but weather usually prevents that, too turbulent/thermal/too hot; or only fly weekends but in that case, I would fly way too little. As in one weekend out of three. Seven or 8 flights per season. So, no thanks.

As long as I fly well above the hilltops they can see me as long as they look. It’s in the landing phase that I must go lower for a while. At that point mr Murphy enters the scene.

Note that this is a very lightly populated area that resembles hilly landscapes in Eastern Europe. Understandably the French airforce likes to train here… And cows don’t protest.
Lining the basket with reflective material would have to be outside where it gets damaged quickly during landings. Otherwise the wicker material disturbs the reflection (we have steel and aluminium fuel tanks inside, steel burners, and that doesn’t help). Nearby primary radar is behind hills when I fly low so would not see me anyway.
Many radar systems filter out anything moving slower than X knots (like 40 knots), and my upper limit for go/no go is 15 knots wind speed which then becomes my ground speed. So they filter me out.
I’m a stealth craft trying to be seen. :wink:

A tricky problem to resolve!

From everything you have said I still think a Trig TT21 Mode S transponder would be the best technical solution.

It would respond to TCAS interrogations from fast mil so they should be able to avoid you!

The volume of space required for the electronics box and display is very small. It is not like you would need to monitor it/change settings, other than switch it on before flight.

Have you considered asking the military, or their controlling authority, what they feel is the best approach for enhancing your conspicuity?



Hi Tony,

Maybe the Trig is the best technical solution (it is conform EASA/French regulations for flights in TMZs or controlled airspace where ATC demands a transponder to allow you into their space) but it still would not fit in my basket. Many balloon baskets are a lot larger, in fact my entire basket is hardly as large as the typical pilot compartment in a large passenger balloon, so they have a lot more space to attach stuff.
See the pic below. Balloon coming towards the camera just before touchdown, pilot (me in light blue shirt and sunglasses) behind the pax. Obviously I can not attach stuff where the passengers are. All four corners of that 110x100 cm interior can be occupied by a 30+ centimeter thick fuel tank; I normally carry three tanks for a one-hour flight, with one passenger (in the pic, the man on the right) pressed in the empty corner where otherwise, tank no 4 would sit. In the pic two tanks are on the left side (right when looking in the direction of flight). They are connected by a fuel manifold that loops around the first-aid kit which sits tight between the tanks. Under that kit sits the EASA mandatory fire blanket (they specify a size that does not exist with commercial sellers of fire gear but I got the closest one, in a soft case because you want as few hard things as possible to bump against on landing). On the opposite short side sit a fire extinguisher in a case plus a 30-meter rolled-up handling rope in a case, the rope under the entinguisher (both are mandatory). I can’t put the Trig above the extinguisher as it would block access, and the corner passenger stretches his arm across that space to hold onto the top ring of the fuel tank to hold on when the basket tops over and he falls on his back. I don’t want an angular object there like the steel case of a Trig in balloon configuration (230mm x 190mm x 65mm, 3 kilos). Which leaves the rear of the basket where I always stand. That’s where my pilot bag sits, and where my pilot safety harness is fitted (also EASA mandatory). Not enough width left there and again, I prefer not to have an angular object in a hard case there. outside is a nono unless I want a 3000 euro transponder kit to be destroyed every season when the basket falls over in an unexpected way (rough ground, sloped etc.).
The second pic again shows the basket occupied after landing. It’s not roomy.
Stuff like the fire blanket and harness that has become mandatory over the last five years or so does not help either. Otherwise I could have put the Trig above the first aid kit between fuel tanks on my right - but now there is the fire blanket… All these things need some access, or they are useless.
Pic three shows the basket on its side during rigging. There is nowadays even more stuff in there, I have moved the balloon bag that historically sat between fuel tanks inside, to the outside of the basket to make room for the fire blanket for instance. Clearly in the pic, there is also no room above the fuel tanks for a Trig or whatever. I can lay my gloves and a map on top of them, that’s all.
So in the particular situation, no, a solid steel case roughly the size of an A4 sheet stood upright and 65 mm thick can’t find a place. Plus there would need to be a suspended reflector under the basket that I would need to hoist inside before landing.
Ask most balloon pilots and they will tell you the same thing. A few carry a transponder in such a battery case because they are close to busy controlled airspace and transport 16 passengers, which leaves them room enough. Their financials also make it viable.
I’ll see of the Great Mute airforce here has a human I can talk to. I can always try to phone them before every flight to warm that there may be a bright blue balloon drifting around here just in case they want to play. BTW, their own rules state that in G space under 500 feet and at 400+ knots, they just have to use their eyeballs and can’t depend on anything else. No time to look at screens. See and avoid.

Now you know a bit more about balloons, lol.

Hi Frank,

I know nothing about ballooning, as you can tell!!!

Could you install the Trig electronics box and battery beneath a new false floor at the bottom of the basket?

You and your passengers would be standing on it, but should be protected by the false floor.

The only thing you would need to mount near you would be the small display/control unit:

I am sure the transponder antenna could be located in a suitable position that means it couldn’t be damaged on landing.

However, this solution does not solve the cost issue….!



Hi Tony, putting the case for the transponder under the floor would lift the floor almost 10 centimeters (we would still need 20 mm of floor thickness to stand on), so the edge of the basket would become too low, increasing the risk of falling out on landing or even during flight. Plus it would add substantial weight, with wood strips, plywood second floor etc. And ballooning is about being lighter than air so any surplus weight is not done. it would decrease the net load capacity too much. Plus, way too complicated. Like needing a charge port in the basket… which sits in my van far from power outlets…
That’s clearly the difference between fixed wing and us - being used to technical solutions for navigation assistance from outside (ATC, traffic separation, ILS, VOR, landing lights etc etc.) and just drifting with the wind and always having to improvise with zero assistance from the ground (that’s the fun, not knowing exactly where you will go and who you will meet after landing).
Traffic separation is important, but statistically, collisions with other aircraft are extremely rare for balloons (it’s mostly balloons amongst each other during mass events, not collisions with other types of aircraft). Most deaths and injuries are the result of either violent landings (high winds, rough terrain) or collisions with power lines during landing approach or when navigating very low. No electronic aids help there.
When I started flying my balloon a long time ago I just had a moutaineer’s altimeter hanging around my neck, no vario, no radio, nothing. Just gut feeling and eyeballs. Legally you can still do that in uncontrolled airspace with a balloon. These days, in spite of GPS, radio, electronic alti/vario, walkietalkies and smartphone with moving map etc., my most important navigation aid is a 2-euro can of shaving cream that helps me to observe the winds below the basket and so anticipate changes in speed and direction as I descend.
I know pilots who were trained more recently and who have loaded their baskets with air nav Garmin gear, tablets with moving ICAO maps and such. It distracts attention from the outside and leads to bad decisions in choosing landing spots. Power line collisions and hard-landing injuries have increased as a result.
Conspicuity devices are at best a neccessary evil (with the possible exception of a solution that lets my ground crew see where I am, which these days means two smartphones running Google Maps sharing their positions). I don’t want stuff that is larger than a handheld GPS in a soft case to do the job. Put it back in my pilot bag after the flight, charge it at home along with my handheld radio and done. A Sky Echo fits that bill, but is not yet certified outside the UK and the US.
Meanwhile I’ll just activate SafeSky and phone up ATC or mil ATC before a flight to let them know that fighter pilots better be aware there is a blue balloon in the area, possibly at or below 500 ft GND.