All very interesting but what about the GA aircraft that dont have £zillions certified kit installed and only fly VFR? What is the experience and recommendations for those types?
The last thing I need is MAC with a prominent Forum Owner.
I have only seen posts where it has gone into confusing detail with no definitive answer.
It’s frustrating, as are many of the responses.
I have seen a map of ground stations but will have to look for it tomorrow. As for altitude coverage surely once we’re high enough for that to be a concern would we need it?
The point is that most UK GA flies pretty low; I’d say 90% below 2000ft. That is where you need traffic most. Above about 3000ft, it doesn’t matter. So a low level coverage map is probably quite relevant.
Admittedly this is a UK-based view, driven by our PPL training and airspace structures, and others can offer other perspectives.
Fenland flyer, please take another look at post no.35
Pls excuse the typo’s. I was walking and typing on a phone.
Your basic choice is PAW, Skyecho, or Flarm.
I have PAW and am happy with it so far, in an update, which I haven’t yet done, it will also receive metars and Taf’s from ground stations.
However it does not provide ADSB out. I have provided that by upgrading my transponder.
Skyecho outputs ADSB but ‘sees’ less traffic types.
Currently Skyecho is not approved outside the UK. (Except Australia) PAW is.
I don’t know much about Flarm outside the faxt that it is prolific in Gliding across much of Europe.
Airborne_Again wrote:
So SIL is used with a completely different meaning than in all other safety-critical systems engineering!? Sigh.What is usually called SIL (System — or possibly software — integrity level) appears to be similar to what is here called SDA…
SDA—System Design Assurance
SIL—Source Integrity Level
Here is a description of the terms as applied to the current DO-260B version of ADS-B Out. It is from the final rule for the US mandate:
6. Source Integrity Level (SIL) and System Design Assurance (SDA) In DO–260A (TSO–C166a) and DO–282A (TSO–C154b), SIL was defined as surveillance integrity level and represented two separate components:
(1) The maximum probability of exceeding the NIC containment radius and (2) a maximum probability of a failure causing false or misleading data to be transmitted. DO–260B (TSO–C166b) and DO–282B (TSO–C154c) separate these two components into two distinct parameters. SIL is now referred to as source integrity level and defines the maximum probability of exceeding the NIC containment radius; SDA now defines the maximum probability of a failure causing false or misleading data to be transmitted. The FAA proposed a SIL value of 2 or 3. A SIL of 2, as stated in TSO–C166a and TSO–C154b, represented: (1) A maximum probability of exceeding the
NIC containment radius of 1×10-5 per hour or per sample; and
(2) a maximum probability of a failure causing false or misleading data to be transmitted of 1×10-5 per hour.
A SIL of 3 represented: (1) A maximum probability of exceeding the NIC containment radius of 1×10-7 per hour or per sample and (2) a maximum probability of a failure causing false or misleading data to be transmitted of 1×10-7 per hour.
The FAA proposed these two values for SIL because its separation standards modeling determined that the probability of exceeding the NIC containment radius must be less than 1×10-7 per hour or per sample and the probability of a failure causing false or misleading data must be less than 1×10-5 per hour. The FAA’s TSOs and the corresponding RTCA documents did not allow for this combination.
Therefore, in developing and issuing the NPRM, the FAA assumed that most operators, in upgrading their equipment for ADS–B, would equip with a global positioning system (GPS) 35 that would provide a NIC containment radius of 1×10-7 per hour (a SIL of 3). However, to require the associated maximum probability of failure causing false or misleading data to be transmitted at 1×10-7 per hour was not only unreasonable but also unnecessary. Therefore, the FAA proposed that a SIL
of 2 was also acceptable.
With the separate SIL and SDA values available under DO–260B and DO–282B, the rule requires a maximum probability of exceeding the NIC containment radius of 1×10-7 per hour or per sample (which equates to a SIL of 3), and a maximum probability of 1×10-5 per hour of a failure causing false or misleading data to be transmitted (which equates to an SDA of 2).
Changing the proposed probability of exceeding the NIC containment radius from 1×10-5 per hour or per sample to 1×10-7 per hour or per sample should not impact NAS users. This is because currently available ADS–B Out systems using GNSS will provide an integrity metric based on 1×10-7 per hour.
Fenland_Flyer wrote:
All very interesting but what about the GA aircraft that dont have £zillions certified kit installed and only fly VFR? What is the experience and recommendations for those types?
Quite simple: Do what you have learned to do: A proper and fact based risk assessment!
Evaluate your risk of a mid air collision w/o any such device
- strongly dependent on your type of flying from quite significant if you are a competitive glider pilot to almost not existent if you mostly fly IFR in the levels
Evaluate the potential reduction of risk by the various devices
- again strongly depending on your type of flying. As a glider pilot a TCAS (and other Transponder based options) is quite useless while FLARM is a great help. For a jet pilot in the levels it is exactly the opposite
Evaluate what gives you the best safety improvement for the money you can spent.
The examples used (glider vs. jet) are obviously the two extremes – but only you can evaluate the right answers for your individual flight profile
I only have PowerFLARM in my aircraft and have previously worked with certification, and would never use Sky Echo or PAW. FLARM is certified by EASA for installation as a minor change (or standard change) and comes with professional external antennas from RAMI. Most GA pilots I know have FLARM as well and have the same opinion about (not using) portable devices for safety.
Somebody said something about speed. FLARM alerts 20 seconds before a collision. The 10-15 km range is more than enough for two aircraft approaching 250 kt head-on.
I have never met anyone with Flarm.
Can flarm show Mode C?
Can flarm show Mode S?
Can flarm show Pilot aware? (At least 7 of us have it now at our field)
Please detail what it can do.
Quite frankly 20 s for a warning is ridiculous.
Flying in the south or south east of the UK requires more than that. My passengers wouldn’t enjoy the severity of avoiding actions required with only 20s of warning each time.
I think I’ll stick with a combination of TS. Good lookout and a wide area overview.
Yes, PowerFLARM Core shows Mode-C and Mode-S. PAW not, but I don’t know anybody that uses that.
20 s is more than you need. Look at your watch for 20 s and you will see. It’s similar to TCAS. You will of course see the aircraft on the display/map long before that.
have previously worked with certification
That’s a useful disclosure of interest Mooney75 – you work[ed] for Flarm. Most people here and elsewhere thought as much.
FLARM is certified by EASA for installation as a minor change (or standard change)
All that means is that in their judgement it won’t affect the aircraft. It says nothing about operation. For example the excellent Golze ADL has a certified display option.
PowerFLARM Core shows Mode-C and Mode-S
It does not, usefully. See above. This trick is being posted all over the place, and most people buy into it.
mooney75 wrote:
The 10-15 km range is more than enough for two aircraft approaching 250 kt head-on.
Can you share the IGC file of a FLARM installation where the forward facing good data range is actually between 10 and 15 km?
Looking at publicly available IGC files, you could be quite happy if the forward facing actual FLARM range is more than 4km.
mooney75 wrote:
20 s is more than you need. Look at your watch for 20 s and you will see. It’s similar to TCAS. You will of course see the aircraft on the display/map long before that.
20s is already quite short, if you accept the fact that FLARM is not like TCAS-2 an avoidance system (that simply requires to pull when the box says pull) but an aid to visual identification. So in this 20s you need to a) realize there is other traffic b) realize that this other traffic is actually getting close to you (one of the problem of these boxes is that 99% of the traffic they show is completely irrelevant as they would not hit you anyways) c) look out of the window to identify the traffic visually d) plan evasive action e) do it.
20s start to not sound a long time anymore – even if it were 20s. With real ranges of FLARM you find in the wild, it is more 6-7s where you have to do this.
That leads to the simple insight that FLARM is completely useless to avoid head on collisions of two motor airplanes in cruise. Fortunately these type of collisions are extremely rare anyways.
