Hot Air Balloon & Radar
 

Just a little survey amongst you ATC people. When hot air balloons are in your airspace can you actually see them on radar, or not at all? (This assumes they are not transponder equipped....) I am interested in the capability of radars to detect small aircraft, and because of the material balloons are built out of, I assume they are one of the most difficult to detect, although microlights and gliders and also probably quite hard.

Never seen Hot Air Balloons in the area, but our Watchman radar has no problem picking up microlights, and even detects parachutes from a paradropping sight a good 15 miles away! :)

Most radars will process out anything travelling at under 30Kts or so as they think its a static object (i.e. terrain) - so won't see balloons. Ours certainly does!

Had one come up as a primary return the other day...but only noticed it after it was reported by a GB A320 on base leg as being same height and 2miles away :uhoh:

Our steam driven AR15 (RIP :sad:) use to see balloons even though it had MTI (moving target indicator - the thing that gets rid of permanent echoes). Gliders and microlights weren't a problem too. I once gave traffic information to a B25 (yep, a B25) that was landing at Bovingdon for filming when the pilot announced he had the traffic in sight, it was 'a large model airplane'. :)

I'm sure I have seen balloons on our ATM, and the police heli shows up when it is doing not many knots.

Our primary radar certainly picks them up.

As well as flocks of geese. Which, especially at this time of year, is very helpful.

The radar will be reflected by the propane tanks which are steel or titanium if the pilot is extremely rich. The pilots watch will also give a good return signal :}

As has been said above, the return will be filtered out as clutter due to the balloon tooling along at 15kts.

A lot of balloonies avoid talking to ATC if at all possible due to lack of practice and the fact that firing the burners makes it impossible to hear the controller. Not firing the burners is rarely a good idea ! They do (generally) know their position with respect to zone boundaries to a high degree of accuracy. Navigating with a GPS, an OS scale map marked with airspace restrictions and with an unobstructed view of the ground is a piece of cake.

Thanks for the replies. I know a balloon instructor well and would be interested in any ATC feedback where balloonies are not talking to ATC and should be. He can then insert it nicely or painfully into their ears, depending on the attitude test! :ok:

Ask your mate to take you on a flight.

I used to bimble over the top of the Benson zone a few years back when they had fewer choppers and I could never get a response. They were either asleep or outside playing golf. :)

On the old 'raw' Watchman displays, especially when the target was close to the radar head (15 miles or less) we'd see plenty; I've passed traffic info on a flock of birds (travelling crosswind, that was the clue!), a bunch of toy helium balloons, microlights. The trouble with a balloon is that it moves with any weather returns so it's harder to interpret.
With the new processed data displays, you lose lots of that ability to interpret returns as they're all dots and crosses now!
One of the balloons that flies in our zone has a transponder and he's REALLY easy to spot now.......:)

Tis a bit hit and miss for us with our 511, sometimes we see them but mostly we don't. PITA when the Bristol or Bath balloon fiestas are on.

You guys will have to educate us non tech types on the radar systems you have, I mean if you can equate some systems to an Austin Metro and some to Ferrari 355 F1, then I can see what you are talking about.....

picking up balloons (geese, parachutists etc etc)... can be done, some radars are better than other, and it also depends on performance on that day, affected by atmospherics, weather and equipment is set up.

If you recall old "steam-drive" wireless...(?) there were days when the reception was loud and clear, but at othertimes it would drift in and out or there'd be some static. In my experience radar works in much the same way.

Will add, crucially, these targets often generate very small weak returns, so another factor is the controller and skill to be able to pick this pin-prick out from other radar clutter (maybe experience, alertness or workload affected). If you are lucky enough to have clutter free radar, then you're probably not seeing these small targets. You can't win?

(Off course if you're required to carry Mode S when mandated the whole situation will change)

Had a report of a balloon in the London TMA the other morning. Was clearly seen on Watchman, about three miles west of BPK, slowly moving south. The scary thing was, it was reported by a Luton departure outbound towards BPK and estimated at 4000 feet! (TMA base 2500 feet!).
With regards to parachutes, had a C130 dropping SF from FL240 on several occasions. The jumpers were clearly visible on the Debden radar. The C130 would spiral down with them and, on occasion, would lose visual contact. As they were still painting clearly, it was possible to pass traffic information to the pilot.

A17

The heli might not be going very fast, but the doppler off the blades is something else!

I would suggest the RCS of propane tanks and burners probably have a higher Radar Cross Section than some GA Light Aircraft which are increasingly made out of composite materials.

Controllers may not necessarily notice a balloon because of its low velocity, therefore the history dots wont be easy to interpret and may just consider it as routine radar clutter.

What with compulsory SSR transponder carriage apparently being implemented in 2008 I understand balloons will also have to carry a transponder. Where they get the power from is anyones guess!

Propane powered . . . . . ? :)

Many commercial balloons already carry a transponder so it doesn't seem to be a problem. Not sure what the battery life is though.

Battery life should not be a problem. In NZ we have areas of transponder mandatory airspace and gliders seem to have no problems keeping their transponders going whilst in such airspace.

Hot Air Balloons
 

Watchman radar picks them up close ish in, say 15 miles . I had one last year and asked him to set QFE and report his height..........eh minus 50ft! My airport on a 500ft hill!
Radar can pick up all sorts, last week I was flying and ATC called traffic right to left 2 nm no height. It was I think the 1415 Cardiff to Paddington GWR train! Up in northern Scotland in the Moray Firth have had oil rigs called to me. Though of course in ATC we have to call any contact.


NM