March 2015

In this month’s edition:

  • Across the Pond – Alcohol Testing – Paul Reilly
  • ADS-B – Should I do anything and if so what? – Steve Hutt
  • Project update: Tony Batchelar’s Aronica – Richard Griffiths

Across the Pond – Alcohol Testing

Some of you in may be aware that I have got myself a trusty steed while I am here in the US. I wanted to choose an aircraft that I can easily bring back to the UK both on a technical basis and to make it through the LAA approval system My choice was obviously from the experimental category so based on my recent flying experience I have got myself a Vans RV12, as the Vans family is a robust choice and it has the quick release wings.

With the aircraft being powered by a Rotax 912ULS I have the luxury (it prefers it) of being able to run the aircraft on Mogas, or as it’s called here is Auto-Fuel. To give you a comparison the current price of 100LL at a nearby airfield, Arlington is $5.47 / US gallon (That’s about £0.91 per litre). I am fortunate that a few local airfields that sell Mogas, although the one I am based at does not sell it . The price of Mogas at the Arlington above is $4.97 / USG (£0.83 per litre). While that feels a great price, certainly compared to the UK , currently around £1.80 per litre ($11.44 / US Gallon) for AVGAS 100LL. I am always looking to reduce my flying costs further regardless of how good the prices are.

As in the UK Ethanol free fuel is hard to find as most pumps sell petrol with up to 10% of Ethanol which as most know is bad for many of the components and it has a higher chance of holding water, both of which is bad for aviation. A bit of surfing and I stumble across a website called . Pure Gas is a website maintained with all the ethanol free gas stations across the US. Couple this with that shows airfields with auto-fuel its great resource combination. Using Pure Gas I located a fuel station near to the airfield (5 Miles) and on a visit a week ago its $2.89 / USG (£0.47 per litre). This is a great bargain, certainly compared to the price across the Atlantic.

For clarity, the price of gasoline / petrol has dropped dramatically since September (almost ½ price in the USA) as an example premium fuel was around $4.60 in the Summer.

With such bargains I would always want to check I am getting good quality fuel and to check its water and ethanol free. Personally, I know I have never really got on with the standard fuel ethanol tester / tool so looked to alternate solutions… Bring on the internet again…Food ColourI stumbled across an article in GA News that detailed food colouring can be used to test for alcohol in gas. In pure gas (Ethanol free fuel) the food colouring will just go to the bottom of the sample and not separate, while the alcohol will dissolve the food colouring into itself fully and the sample changing its colour as an indicator. While being sceptical I thought it was worth a try. In order to keep the price of the experiment down I picked up a pack of food colouring at Dollar Tree (The US equivalent of Pound Land). The benefit of this is I could try each colour for results to see any difference.Fuel testSo I picked up fuel from my fuel from two source one fuel station. The first was one from a source known to have ethanol (left) and another from the fuel station listed to have no ethanol on the pump and on Pure Gas website (right). I tried each bottle and found the green to have the most visible result by putting two drops and swirling it around to mix it. The results were pretty conclusive that the test seemed to work very effectively with the ethanol fuel turning green. This is definitely something I will be keeping in the car to test a sample fuel prior to putting it in the aircraft.

Paul Reilly

ADS-B – Should I do anything and if so what?

A question posed on RVSqn by Gareth Hardwick and a response by Steve Hutt.

I have been trying to learn/understand what this all means.

I have a share in an RV6 with steam gauges, and a mode C transponder and we have been debating which way to go on an up-grade, after sorting the radio to 8.33.

If the CAA are running trials now with non-certified GPS’s and ADS-B out broadcast through a mode S transponder, but with a view to dropping mode S in 2020 should we replace our transponder with a mode S or is there likely to be a cheaper alternative to send a ADS-B out and hence will we have wasted our money on mode S?

We use Skydemon on an ipad and a GNS 2000 GPS for GPS nav and I saw mentioned by somebody that it was likely Skydemon would support the ADS-B in, it was however unclear to me which bit of kit would receive the signals and send them to the ipad?

Look forward to some of you experts helping us mere mortals to potentially not waste our money jumping on the back of a wave instead of waiting for the next one

Gareth Hardwick G-BZWZ

Hi Gareth,

OK. You said “I have a share in an RV6 with steam gauges, and a mode C transponder and we have been debating which way to go on an up-grade, after sorting the radio to 8.33.” & “We use Skydemon on an ipad and a GNS 2000 GPS for GPS nav”.

Regarding ADS-B, first and foremost, you do not HAVE to do anything.

The current EASA ADS-B regulations which mandate ADS-B only apply to a/c above 5700Kg or faster than 250Kts TAS and also only apply to ADS-B Out and require certified equipment.

Now, if you are minded to get involved in ADS-B and choose voluntarily to do something about it then read on…..

So… let’s first talk about ADS-B Out – using ADS-B as a means to make your aircraft ‘visible’ to ATC/other aircraft that are equipped with ADS-B receivers (ADS-B In).

The recent discussions regarding uncertified GPS and ADS-B Out are interesting, but only relevant to those that already have a Mode S ES transponder and a suitable portable aviation GPS that can output NMEA data down a wire (your Bluetooth GNS2000 GPS does not do this). If anyone has these or is happy to buy/install them then go ahead and register for the NATS trial, get your Minor Mod and go fly. If you are buying a Mode S transponder then the 2010 Eurocontrol document I referenced previously stated that Mode S would be around until about 2025 atleast. Trig TT22’s are advertised for £1800 or max of £180/yr over that expected life. NB. The equivalent unit if bought as part of a Dynon Glass Panel upgrade costs £1440 or £144/yr. Garmin seem not to want their transponders involved in this uncertified GPS/ADS-B idea but Trig, Funke and Garrecht Mode S transponders will be fine. Maybe some others too as long as they have the Extended Squitter feature.

Note that if the NATS uncertified GPS ADS-B trial were in the end to be deemed a failure then the current EASA rules insisting on certified GPS position data would continue, which would be an enormous impediment. There is not and never has been anything (excepts cost!) to stop anyone connecting a certified GPS to their Mode S ES transponder, getting the paperwork sorted and broadcasting ADS-B Out.

An alternative to Mode S ES for doing ADS-B Out is the idea of an all-in-one box that just does ADS-B but does both ADS-B Out and In. There is a newish TSO in the US called TSO-C199. This is a specification for an ADS-B In and Out box with an off-the-shelf GPS chipset that is aimed at a/c that do not have a transponder. The NATS-sponsored Low Power ADS-B Transceiver (LPAT – also with an off-the-shelf GPS) is a similar box, though NATS are saying it cannot be used in an a/c that has a transponder. It is not clear to me exactly why there should be a conflict between an LPAT and a transponder in the same a/c. Maybe it is just a testing issue and hopefully they will address this shortcoming in the future. LPAT is being manufactured by Funke and apparently is not dissimilar to their TM250 with the addition of ADS-B Out but is a portable unit, not panel-mount. Like the TM250, LPAT will detect Mode A/C/S and ADS-B targets. But LPAT has only just commenced flight trials so will not be a viable option for a while and even longer for those with a transponder. AOPA are recruiting testers right now. The fact that LPAT uses a commercial uncertified GPS chipset and is supported by the CAA should offer hope for the uncertified GPS/Mode S ES ADS-B Out trial.

Now for ADS-B In and associated Collision Warning Systems (CWS)

If you are interested in a CWS there are various dimensions to a decision to go ahead. As has been seen, there are some who think any extra kit in the panel will distract from lookout. And there is the further argument that a traffic warning on one bearing may divert attention from a potential additional conflict on another bearing. Against arguments is the benefit of being warned of traffic conflicts that just plain could never be seen, such as immediately aft below. Mark One eyeball is not 100% reliable but neither is CWS as it will never detect a/c without transponder or ADS-B Out.

If you still want to buy a CWS you want one that provides an audible alert, preferably through the intercom. If you are looking for a graphical display of traffic then there are options of dedicated traffic displays or traffic symbol overlay on moving maps and even incorporation into 3D terrain/highway-in-the-sky-type displays! These all have their own pro’s and con’s, both in usage and panel space requirements.

CWS that detect aircraft with Mode A/C & S have been around for many years. Most have no graphical display and do not offer any bearing information, just relative altitude (from the Mode C/S signal) plus estimated distance based on signal strength. FLARM, which has come from the glider community, is another broadcast electronic conspicuity system that work in a similar fashion to ADS-B, and is in use in some powered aircraft too. And then there is ADS-B In.

So there are Mode A/C only CWS; Mode A/C/S CWS; FLARM only CWS, and ADS-B only CWS. And there are combination system CWS that cover two or three of these, in some cases incorporating FLARM transmission too. Clearly, because it is very early days for ADS-B, having a combined system CWS is more than a little helpful.


Garmin have their GDL39 which is a portable GPS & ADS-B In device with no screen that provides wired or Bluetooth GPS & traffic data output in Garmin TIS format to Garmin and other TIS compatible displays or Garmin Pilot iPad app. The GDL39 receives on 1090MHz and also the US-only 978MHz UAT (Universal Access Transceiver) datalink.


The Funke TM250 mentioned previously is a dedicated 2.25” panel-mount traffic display unit with audio warning for Mode A/C/S, FLARM and ADS-B In.


PowerFLARM (offer a collection of devices with varying feature sets, some portable, some fixed install to feed their own dedicated CWS display or other manufacturer’s MFD. The highest spec unit have a built-in GPS and supports detection of Mode A/C/S, FLARM and ADS-B In plus FLARM transmission. Data outputs can be in FLARM NMEA format or Garmin TIS format.


Air-Avionics offer a very similar collection of devices to PowerFLARM, even using lots of common hardware but with their own software. The Air-Avionics top-end units; one 2.25” panel mount with built-in dedicated CWS screen; one fixed install with no screen, have a built-in GPS and support detection of Mode S, FLARM and ADS-B In plus FLARM transmission. Data outputs can be in FLARM NMEA format, Garmin TIS format or even ARINC429.

Air Connect

Both PowerFLARM and Air-Avionics can be connected to the Air-Avionics Air Connect unit that can be used to transmit traffic data via an in-cockpit wifi network for receipt and display on a tablet running a compatible app. Skydemon for instance has a dedicated mode it can be run in which overlays the traffic data on the moving map and even uses the GPS data fed via Air Connect.

Lots and lots of options! I’m sure there are other suppliers, particularly in the USA many of which are built on the US-only 978MHz UAT standard or dual UAT/1090MHz datalink standard.

Just to reiterate, nobody is being forced to spend any money on ADS-B or CWS of any form and, because it is early days for ADS-B at least in the UK spending money is not without some regulatory risk. If the uncertified GPS position data is not in the end permitted then the take-up of ADS-B Out will go VERY slowly if not stall in UK GA so ADS-B in only investments may have little to detect. The combined systems however would continue to give benefit albeit not offering the precision of ADS-B.

Personally I like having a CWS and like the idea of being as electronically conspicuous as I can be to as many as will set themselves up with CWS. I’m also going to paint my plane in dark colours to improve visual conspicuity too 🙂

Steve Hutt

Project Update: Tony Batchelar’s Aronica

Tony’s half restored Aeronca Chief took its first trip a couple of weeks ago when it was towed from the workshop at Ripe it’s been slowly coming back together in, to its new home at Swanbrough Farm Airfield.

Uncovered aircraft in shed.With some ingenious use of planks, settee cushions, rope and gaffer-tape the wings were jury-rigged to the fuselage.  Javid Azadi certainly knows his knots.

Landrover Freelander with aircraft on tow hook.Tony Palmer had engineered a brilliant tow-fitting; a tow-ball socket fixed to a piece of angle iron.  This was bolted on in place of the tail wheel and hefted on to the tow hook on the back of my Freelander.

I drove slowly, in a procession with Javid path-finding in front, and Tony nervously behind ready to collect any bits that came loose. We made several stops to check things were staying put – and remarkably they did.  Even up the extremely rough track at the airfield.  Everything went fine – right up to the point where we manhandled the aircraft into the hangar – and scraped a bit of a wing trailing edge on a roof girder! :-O  There’s a lesson; don’t relax when you think it’s all done – it isn’t!  The damage is tiny and won’t delay getting her in the air come the summer.  (That’s right isn’t it Tony….)

Richard Griffiths

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