Yesterday I had the chance to test SafeSky on a flight for the first time. I use it in combination with SkyDemon.
It helps to show other aircraft in your vicinity. That makes it useful.
But for Mode-S transponders the track of the shown aircraft is very inaccurate.
Also the position indicated of other aircraft compared to the own aircraft of those mode-S aircraft is too inaccurate, meaning that the direction to look for the other aircraft can not be sufficiently determined.
Every aircraft where the position is measured with MLAT can be in accurate since their location is based on timing and receivers run by people that run the receivers as a hobby.
It really depends on a lot on how many of these relievers are at a location to give more accurate answers.
In Europe, at least where I fly I also see that not to many people use safesky so no additional accurate reporting is done…
Your conclusion is correct, safesky is more like traffic awareness (like they advertise) and should not be used as traffic avoidance
RVT is correct in what he says. MLAT tracking isn’t always accurate due to a number of reasons, the main one being the lack of MLAT receivers in your area.
However the altitude of the MLAT detected aircraft, relative to your “own-ship” altitude, should be accurate.
All the explanations below are correct: Since Mode-S transponders are not connected to a GPS, Mode-S can only be multilaterated and inherently imprecise by design. (By the way, this is not specific to SafeSky, ATM systems have similar visibility limitations). But altitude will be correct as it’s transmitted by the transponder.
For situational awareness, the usability of Mode-S traffic data can be effectively managed through the user interface as we do in the SafeSky App:
Looking at the screenshot below, in the SafeSky display, an uncertainty circle is shown based on position accuracy (which depends on the number of ground stations in sight) and the aircraft’s velocity. This circle indicates the plausible location of the aircraft. In contrast, the helicopter shown in the screenshot is transmitting via ADS-B, which provides better positioning and is therefore displayed without an uncertainty circle.
When SafeSky is used with SkyDemon over GDL90, this position accuracy information is passed along but is not visually represented in SkyDemon. This could be something worth suggesting to the SkyDemon team?
To get the most of both worlds, I personally use an iPad in Split View mode. In SkyDemon, I gain a broad traffic awareness (such as detecting a cluster of gliders 10 minutes ahead, which isn’t an immediate danger but could prompt me to adjust my route slightly). Meanwhile, the SafeSky radar view provides proximity alerts, helping me stay focused on visually scanning outside when aircraft are in close range.
I want to emphasise that flying VFR remains the fundamental rule for our flights. As many pilots have reiterated, SafeSky is a situational awareness companion and should be used as a complementary traffic awareness system, not as a tactical deconfliction tool.
Fly Safe everyone,
Tristan
I used Safe Sky for a while in the UK. I now use a Pilot Aware Fx.
I found that the traffic from Safe Sky is consistently a bit late. Whereas from PAFx it’s where it is on the screen. That means that with SS you regularly spend time looking for something because it’s on the screen but isn’t quite where you’re looking. At 150kts that’s a very bad position to put yourself in - shit happens quickly! My closest call with another aircraft was primarily because I wasn’t looking for it in the right place using SS. I’m yet to experience that with PAFx because it isn’t primarily a mobile network derived device. Personally, I think that makes SS dangerous if you’re a 100kts + cruiser and more of a hinderance than a help. Fly the aircraft, get yourself a good ATC service and look out the window! I say this because people should be very aware of the limitations that surround the SS App.
Of course traffic avoidance is always visual. But the awareness should not provide information and present it as accurate and correct when it is not. That is a UI design principle.
On a phone screen that is not really an option. and I am not going to buy an iPad for it.
Also in SafeSky the track arrow is not accurate/correct. That should also be shown as a line with tolerances in that case.
As long as SkyDemon does not show the accuracy information, I wonder whether it can show another symbol in SkyDemon for an accurate target (ADS-B or SafeSky user) or an inaccurate MLAT target.
Here I fully agree, you are looking for a target in the wrong direction/distance.
That means the UI should cater for the inaccuracies, also when only using SkyDemon as a display of the information.
At least inaccuracy should be indicated in some way:
If a location accuracy can not be drawn in the display software, another symbol might be a solution.
For an inaccurate track vector that vector better gets removed.
