Peter wrote:
Visibility in aviation is always determined (by humans) by looking for objects at a known distance.One also has to do it along the appropriate axis, because the mist varies from place to place, and because the position of light sources affects how far the observer can see. For example in the video in question there is a light source shining into the camera, while the pilot is looking at about 90 degrees to it.
Exactly. Low sun and haze/mist means maybe in one direction 1 km of vis but 10+km the other way…
And in my experience, cameras can make things look better than they or or worse than they are in equal measure…
I wouldnt judge the guy taking off as I wasnt there in his cockpit at the time.
More alarming to me is the guy that sent the footage to a media outlet… not someone Id want on my airfield.
Regards, SD..
Visibility in aviation is always determined (by humans) by looking for objects at a known distance.
One also has to do it along the appropriate axis, because the mist varies from place to place, and because the position of light sources affects how far the observer can see. For example in the video in question there is a light source shining into the camera, while the pilot is looking at about 90 degrees to it.
Dimme wrote:
I envy pilots able to judge anything less than 8000 m visibility. That’s some serious dynamic range for the mark I eyeball right there.
Objects at a known distance…?
Malibuflyer wrote:
There are so many pilots I envy because they are able to judge flight visibility of a flight they haven’t done themselves from a picture/video that was taken significant off the runway in a direction perpendicular to the actual flight direction in weather conditions with patchy ground haze/fog. I would never be able to do such a thing!
I envy pilots able to judge anything less than 8000 m visibility. That’s some serious dynamic range for the mark I eyeball right there.
Malibuflyer wrote:
Even more interesting, I got the impression that especially these pilots are extremely good at estimating such visibilities from pictures, who at their own VFR flights often pretend it is impossible to know if you are more or less than 1000ft vertically separated from clouds.
I think for takeoff on runway, it is easy to judge visibility, North Weald is 2km long and if I can see the end I have enough visibility, one day it was 10km visibility at 500ft but I barely managed to find the runway as I turned crosswind 
For the case of landing after engine failure, that would have been interesting in low IMC, but the marginal risk of weather on EFATO is highly exaggerated by pilots, personally it’s longer a worry 1/ the choice would be as limited as any takeoff in good VMC and 2/ the risk of engine failure is very small
Obviously, to pull up a textbook forced landing back on sub-1km runway you need min 2000ft agl altitude, which needs 3km visibility to make the circuit and 3000ft agl ceiling to keep legal VMC in class D, that would make any SEP IFR ticket worthless and by the way how this risk is mitigated for IFR on 5deg SID/STAR or 3deg IAP when most of the SEP can barely glide 1:10?
At 500ft agl EFATO at VX, you will only make the 200m ahead
Others may have sophisticated or informed opinions on this but I personally no longer care about the defensive SEP engine failures planning (I also fly night, low IMC, gliders), IMO as long as I put enough fuel and manage engine & speed properly, the risk is well mitigated by sub-50kts touchdown speed and wing level rather than what is ahead/bellow (had few off-field landings in Gliders/TMG, one forced landing in SEP in a field, one EFATO in Cub landing on whatever left, so far the only notable mis-shape was glider in 3 feet tall corn field )
Jacko wrote:
Just lift the tail?
Not my aircraft, I was told not to taxi that way…
In low visibility the owner can’t see me
I agree totally with Malibuflyer re the judgement of visibility but what I am not sure about in this thread is a) Are we talking about taking off VFR in low or zero visibility? b) taking off in IMC under VFR? c) take off in IMC under IFR.?
I will stick to my point that even for IR pilots with a lack of currency the transition from external visual clues to internal visual clues in white out conditions is one of the most dangerous parts of flight into IMC. Just read the NTSB reports, particularly those regarding LOC in Alaska and IIRC California and Oregon.
Insight of the discussions at the airport on this case over the weekend:
There are so many pilots I envy because they are able to judge flight visibility of a flight they haven’t done themselves from a picture/video that was taken significant off the runway in a direction perpendicular to the actual flight direction in weather conditions with patchy ground haze/fog. I would never be able to do such a thing!
Even more interesting, I got the impression that especially these pilots are extremely good at estimating such visibilities from pictures, who at their own VFR flights often pretend it is impossible to know if you are more or less than 1000ft vertically separated from clouds.
Ability to estimate vertical and horizontal distances somehow seems to be negatively correlated …
Peter wrote:
but the article alleges criminality, which is a different thing
Where do they do that ? They say it was dangerous and that this kind of takeoff can end fatally and so on. It is written in a sensationalist manner and a mixup of everything, which is exactly what you’d expect from ‘Blick’. You’re right in that they will have to prove it, but you know very well the potential result when this goes to an ordinary court. The real outrageous thing is not the start, but the fact that every Tom Dick and Harry can film you and start a shitstorm that way.
Must’ve been a slow news day in Switzerland.
he relied on luck to be able to come back.
It was the media article which said one needs to be able to land back, which was a new one to me.
Practically, most people won’t depart if they can’t come back, if they are doing a local flight, because it is just a big hassle then. But if going somewhere else, and staying there for a bit, there is no such practical requirement.
One can criticise, discuss, etc, and that’s fine, but the article alleges criminality, which is a different thing. The OP hasn’t been back, too…
After he’s been ratted out he’s gonna have to explain it to the bazl.
If they follow the law, they need to prove (to whatever is the required standard in the country in question) that he is guilty of breaching a law. In any civilised country, he doesn’t have to explain anything.
