Say we are going in the same direction, class E airspace, he is 100 kts slower than me, I overtake lower and on the right hand side, have him clearly in sight all along. What is a “safe distance”?
Conversely, I read some airprox reports recently and it just got me wondering, if one of the pilots claims he had the other one in sight and kept a safe distance, can he ever be blamed/prosecuted?
I mean in the above scenario, the overtaking plane is fully in control and might feel safe, but the slower plane might see it completely differently, as it would be a big surprise to him, therefore different risk perception.
IFR separation via radar is 3 or 5 NM where I fly. I don’t usually pick up traffic visually until inside 2 NM. I would keep a wide berth if possible and if in sight, would overtake to the right about a mile apart. If the other aircraft is not aware of your presence, it is unlikely they will see you. We now have the advantage that most aircraft are either transponder or ADS-B Out and transponder equipped, with portable receivers and will see most traffic on the panel equipment or on an iPad long before you see each other visually.
Thanks for raising the subject @HBadger
The airprox reports you might be alluding to might be from the Swiss SUST which lately seems more interested into nice and easy to investigate airprox or begnin occurrences, rather than shedding some light on some of the accidents with serious or lethal outcomes (a good example being the homebuilt Lancair Legacy HB-YMS, AFAIK only a summary enquiry on the horizon despite the loss of 2 people)). A shame really.
As to your original question, I’m sure a few EuroGAers are right now digging into their law books or other online jurisprudential reference to find the finite answer… good luck on that 
My practical answer? Enough distance to: A/ not startle the other traffic, and B/ able to avoid, by a safe margin, said traffic whatever maneuver is initiated by the startled, or not, traffic concerned.
Since the environment is highly dynamic and conditions dependent, factors to be taken into account are multiple. Examples: Visibility, TAS, density altitude (true altitude), airplanes config, closure rate, delta speed, pilot average reaction time, etc, etc.
Considering and applying all given factors, a scientific answer might be found…
Depends if it’s in circuit? gliders?
I think less that 0.5nm is called loose formation flight (one wing span is tight) and higher than 3nm is not visible by naked eye, so it’s somewhere in between?
Conversely, I read some airprox reports recently and it just got me wondering, if one of the pilots claims he had the other one in sight and kept a safe distance, can he ever be blamed/prosecuted?
Do people get blamed or prosecuted for airprox while flying? I mean not in higher controlled airspace where PIC bust his clearance, level or heading and ATC gets sent to jail after loss of separation
>> Do people get blamed or prosecuted for airprox while flying?
Honestly don’t know, probably not.
But there are quite a some SUST reports, one extreme example I recently saw was a PC6 diving down (I believe with reverse thrust in-air) after a jumping operation and nearly missing a cruising Cessna (?).
@dan a shame that HB-YMS is not further investigated. Wasn’t that the one where aerodynamic improvements were made not too long before the crash (vortex generators to decrease stall)? Always wondered if there is a connection to the crash.
Here is another one thats interesting: https://www.sust.admin.ch/inhalte/AV-berichte/A108_HB-FKL.pdf
It explicitly says: no minimum distance is prescribed, and basically concludes that it would be advisable to have flarm if you buzz around at 275kts in airspace E at 2400ft near an airfield, in formation (duh!)
Dan wrote:
As to your original question, I’m sure a few EuroGAers are right now digging into their law books or other online jurisprudential reference to find the finite answer… good luck on that
I’m certain there is not regulation about this. Not only for VFR in VMC either, but in every situation where ATC does not provide separation. It’s a judgement call.
In absence of ATC separation, don’t VMC minima for distance from clouds and semi-circular cruise levels indicates how much one need to stay away from other traffic?
I would say,
*The 500ft depends if heading converging/opposite and VFR/IFR, I am taking the lowest value between unknown traffic, the 1500m is the lateral distance from clouds
**In countries that allow VMC with clear of clouds near the ground with speed under 140kias, so you can have two traffic with 1m & 1ft appart
Ibra wrote:
less that 0.5nm is called loose formation flight (one wing span is tight)
Have done some formation flying with the RV-Pilots.eu guys, and the used reference for RVs is the Formation Guide from FFI
The largest separation is found in the guide and defined as: Route formation is flown 2 to 4 ship widths wide
Obviously the other positions are in closer proximity 
Airborne_Again wrote:
there is not regulation about thi
Had a quick search, and could not find anything either.
@HBadger, agree on all counts re YMS.
In addition to the above, FFI also offers formation type supplements for the Bonanza, the Mooney, and the LongEZ/VariEZ
