Whether continued vmc flight into IMC covers 100% of scud running accidents would need careful study of the NTSB/AOPA Safety data base, but it must be a high . Then this cause is usually associated with around 25 of GA fatalities.
High time experienced pilots succumb in places like Alaska where they probably know the routes better than most.
Multi crew SOP is highly sensitive to MSA. The crew brief and announce when it is achieved, brief if a cleared altitude/FL is ‘safe’ in descent. Whether an altitude is ‘safe’ on radar vectors (using the MVA chart where relevant).
I like Graham’s definition which enshrines this MSA awareness as a risk parameter.
The beauty of the Maule and Super Cub undercarriage is that precautionary landings are a natural risk management tool.
I think much depends on where you are doing it.
For me, since a year or so after I got the PPL, my immediate Plan B for this situation would have been to climb up, into IMC as necessary.
The problem is that if you do that in the UK, you are quite likely to get the special CAA treatment and are risking losing your license pretty fast if you repeat it.
Why?
Because the reason you were scud running in the first place is prob99 because flying higher up is not possible, due to the CAS base.
All cases of me flying low down in crap wx in the UK were due to the base of CAS and the impossibility of getting a clearance into it (Class A).
Doing it in mountains is something else… In 2004 I did a flight in Switzerland, from Wangen Lachen to Sion, and back (carrying a passenger collecting a plane from Sion on the way there) and my Plan B was to climb. In the mountains there is no practical CAS enforcement until you are well above the terrain (irrespective of what the map says) because they can’t see you.
However all these escape routes do involve flying in IMC. You aren’t legally “VFR” then 
but more importantly you need to be capable of doing it safely, in terms of pilot skills, aircraft capability, and knowing the aircraft systems well enough to fly it in IMC.
RobertL18C wrote:
I like Graham’s definition which enshrines this MSA awareness as a risk parameter.
The beauty of the Maule and Super Cub undercarriage is that precautionary landings are a natural risk management tool.
To get an MSA you need a route which you don’t have yet as your previous route did not allow flying above MSA…
I think people will still crash even if they have APs hooked to 500ft agl radar altimeters, unless they can press some +10kft/min climb, 35kts, 200ft radius turn buttons 
If you can’t maintain MSA turn back or carry out a precautionary landing.
Obviously Rule 5 sightseeing can be carried out in good VMC below MSA.
Graham wrote:
When you need to descend to remain VMC, but based on the terrain you’re not comfortable with making that descent. That’s my definition.
A good definition, but I would also bring in the visibility as well as the terrain.
I have never heard of “scud running” until I got to EuroGA. It is still not clear to me exactly what is meant. Flying at minimum ceiling (500 ft) is no problem. Flying at minimum vis (1.5 km) is close to impossible, over any length of time at least. Before EASA regulations, and still valid for Annex 1 aircraft, we have/had planning minimums and operational minimums.
Planning minimums are:
Operational minimums are whatever the airspace/regulations say. Basically only 1.5 km visibility in G. But also practically 500 feet ceiling due to regulations for minimum alt. Flying at planning minimums is business as usual, except maybe for visibility. 5 km visibility is not a lot if you are unknown, but with GPS – no problems. However, 1.5 km visibility?
@Alioth
Fair enough. I should add 500 feet over the water is fine when in sight of land and when following the coastline to an airport on the coast….
Out of sight of land, you do have to be ready to fly on instruments.
Airborne_Again wrote:
A good definition, but I would also bring in the visibility as well as the terrain.
A fair point I think. What if I re-write it to:
“When you need to descend to remain VMC, but based on the aircraft, terrain and weather conditions you’re not comfortable with that descent”.
Building on context being everything, my own attitude to it has morphed a little since flying the Vagabond. Back when nearly all my flying was in the TB10 I always favoured gaining altitude and would definitely climb into IMC rather than get into any terrain-hugging fun. Even when my PPL instructor was telling me “maintain VMC at all costs” the know-all part of my brain was correcting her words to “actually, maintain MSA at all costs – you can fly on instruments but you cannot fly through rising ground”.
With no gyros, a much slower cruise, and the ability to land and stop in <200m of anything vaguely resembling grass the situation is a little different. A major factor is that the precautionary landing becomes a real tool that can be used with an expectation of flying the aircraft out another day, rather than just a last resort to preserve life when things have really turned into a load of no fun.
Last flight before the lockdown (in the Vagabond) I hugged the terrain back to base for about 1hr 15mins to stay out of a strong headwind. The 500ft rule (judged by eye) was in play for most of it – I flew as low as was legal. It was severe CAVOK and it was a very good learning experience: I could plan my route at a tactical level by looking a long way ahead and skirting around the highest hills, but what I really took away from it is that I wouldn’t like to have done it in poor visibility, nor with a low cloud ceiling that would have prevented me bailing out of the exercise by giving it full power and best rate of climb airspeed.
Graham wrote:
but what I really took away from it is that I wouldn’t like to have done it in poor visibility, nor with a low cloud ceiling that would have prevented me bailing out of the exercise by giving it full power and best rate of climb airspeed
As always try before you buy
What are the thoughts on flying low over the sea if the view starts to get a bit fish-bowly? I have heard a lot about the risks of misjudging altitude over calm water but little about the same risks when flying over the sea, which is less likely to be still as a millpond than your average lake.
One would imagine that the lower you fly, the less likely you are to lose the horizon but the more likely you might be to collide with the water.
