Plane Crash in Blizzard-Like Conditions Kills 9 in South Dakota.

[Evan]

You're gonna love this, but Icing seems to be one of those very black and white things...If you need it, get it, or don't go...

I think D.I.Y. de-icing adds plenty of grey area.

Finally- someone also pointed out that the plane apparently doesn't really seat 12....so a big load of passengers and guns and game and luggage...W & B gets suspicious (along with W & B AND icing together and so on and so forth).

It's not out of the question. MTOW is 10,450lbs. They had about 650 miles to fly, so guesstimating 1600lbs of fuel would leave them about 2650lbs for pax and cargo. Two pax were children and at least one was elderly, so figuring an average of 150lbs x 12 pax still leaves you around 800lbs for luggage, gear and whatever beasts you're dragging back home. There are no elephants in South Dakota, although there may be a stray moose... And all of this assumes the wings are still wing-shaped.

[3WE]

Referencing 14 CFR 91.175(f)(2), standard takeoff minimums are 1SM or 5000RVR (if available) for aircraft with 2 or fewer engines unless specifically authorized or published otherwise.

3BS...Busted talking out of his ass.

And suddenly, this takeoff is looking as it might be illegal- reported visibilities around 0.5 mi.

[Gabriel]

Referencing 14 CFR 91.175(f)(2), standard takeoff minimums are 1SM or 5000RVR (if available) for aircraft with 2 or fewer engines unless specifically authorized or published otherwise.

But does this rule apply for a private flight in a GA plane?

(f) Civil airport takeoff minimums. This paragraph applies to persons operating an aircraft under part 121, 125, 129, or 135 of this chapter.

[Evan]

Referencing 14 CFR 91.175(f)(2), standard takeoff minimums are 1SM or 5000RVR (if available) for aircraft with 2 or fewer engines unless specifically authorized or published otherwise.

What does having a third engine do for you here?

The old rule in driving school was 'don't overdrive your headlights', in other words, your visibility must exceed your stopping distance. Shouldn't that be the rule in aviation as well? Takeoff minumums calculated before takeoff specific to the aircraft and TOW, based on stopping distance needed from V1? Onboard computers are good at that.

[BoeingBobby]

Part 91 flight. I am still looking for reference to de-iced/ anti- ice.

[Gabriel]

What does having a third engine do for you here?

It improves your climb gradient and hence obstacle clearance (obstacles that you can't see) in case of an engine failure.

The old rule in driving school was 'don't overdrive your headlights', in other words, your visibility must exceed your stopping distance. Shouldn't that be the rule in aviation as well?

No. In aviation you know beforehand how much tarmac you have ahead and you know (or count with) there will be no other vehicles, traffic lights, pedestrians or curves ahead.

[3WE]

No. In aviation you know beforehand how much tarmac you have ahead and you know (or count with) there will be no other vehicles, traffic lights, pedestrians or curves ahead.

Indeed.

However on the other end of the scale, I think most takeoffs are highly dependent on seeing a centerline (or runway edge) markings/lightings....so you need some visibility....and I would guess that 0.5 miles is enough to keep on the runway.

By the way to HELL with Part 121, Part 91, etc. if you can't see the runway, it's not good.

(Yes, I'm sure that TOPMS and GPS/RTK auto-takeoff is within the realm of automation).

[ATLcrew]

But does this rule apply for a private flight in a GA plane?

It appears it does NOT apply, which means he could legally take off all the way down to 0/0.

[Gabriel]

It appears it does NOT apply, which means he could legally take off all the way down to 0/0.

Yeah, well, it is known that some things are stupid even if they are legal. Hence the 3we's reasoning.

I wonder if a take-off in 0/0 would violate the "no reckless or careless flight allowed" provision, which does apply for all types of operations.

[Evan]

It improves your climb gradient and hence obstacle clearance (obstacles that you can't see) in case of an engine failure.

Right. In case you need to climb to avoid an uncharted obstacle that you can't see. Except, that there's nothing you can see that would cause you to do that.

I'm pretty sure single-engine ops allows for known obstacle clearance. If not, I'm taking the train.

No. In aviation you know beforehand how much tarmac you have ahead and you know (or count with) there will be no other vehicles, traffic lights, pedestrians or curves ahead.

Isn't the entire point of visibility to be able to detect things that are not known to be there? Otherwise, why do we need it? And isn't the other point of visibility to be able to do something about it, which, at high-speeds on a runway, means being able to stop before hitting them? It doesn't seem too beneficial for a pilot to be able to say, "oh, there's the snowplow that isn't supposed to be there, the one we will now plow into." But that is exactly what it comes down to if your minimum visibility is shorter than your stopping distance.

[3WE]

Isn't the entire point of visibility to be able to detect things that are not known to be there? Otherwise, why do we need it?

Interesting argument...

Using that thinking, I believe that all Cat II and III (especially) approaches should be banned and Cat I minimums be revisited to be sure airplanes can stop for undetected school busses full of nuns..

Indeed we had planes bearing down in New Yark at 100+ kts while an MD-80 was doing some off-road ATV exercises unbeknownst to the tower or the approaching aircraft.

"Why do we need it" I was THINKING we "need" about 100 ft to be able to see the centerline and runway edges...but thinking is dangerous, of course.

Edit: I missed the exact quote Flyboy mentioned:

It doesn't seem too beneficial for a pilot to be able to say, "oh, there's the snowplow that isn't supposed to be there, the one we will now plow into.

So let me RESTATE, if you are worried about this, we need to ban all Cat III, II AND UPDATE, CAT I instrument approaches and landings due to the risk of snowplow collisions.

https://en.wikipedia.org/wiki/Ozark_...nes_Flight_650

Snowplowman did died , but the aeroplanie lived- when the wing from the classic smoking-in-the-lavatory total air disaster was moved to this aircraft.

[ATLcrew]

It doesn't seem too beneficial for a pilot to be able to say, "oh, there's the snowplow that isn't supposed to be there, the one we will now plow into." But that is exactly what it comes down to if your minimum visibility is shorter than your stopping distance.

Holy Cats!

[Evan]

Interesting argument...

Using that thinking, I believe that all Cat II and III (especially) approaches should be banned and Cat I minimums be revisited to be sure airplanes can stop for undetected school busses full of nuns..

Indeed we had planes bearing down in New Yark at 100+ kts while an MD-80 was doing some off-road ATV exercises unbeknownst to the tower or the approaching aircraft.

"Why do we need it" I was THINKING we "need" about 100 ft to be able to see the centerline and runway edges...but thinking is dangerous, of course.

Not dangerous, but obviously wrong since the FAR's don't mention anything about 100ft. But you make a good point that a "blind" take-off is essentially the same as a "blind" rollout. If someone leaves a snowplow on the runway, well that's life (although I'm a big fan of ground-radar requirements at commercial airports).

Now, to try and answer my own question (as ATL's answer was a bit vague):

Visibility restriction in IFR is only concerned with what goes on below minimums. Unless you're doing an autoland, you have to have visual contact with the runway so you don't land in the In n' Out Burger drive thru.

Once you take-off, assuming you remain on the approved departure route until you get to minimum safe altitude, visibility isn't really an issue (I'm assuming diligent instrument-rated pilots here).

So, as I understand it, the main issue is an immediate return. You must have enough visibility for that. A single experiencing an engine failure HAS to return. A twin that loses an engine has to return to the nearest suitable airport (in point of time, of course) and with one engine remaining you don't want that to be too far off. A triple or quad-engine aircraft could more safely transit to a further-flung (but more 'suitable') alternate. That's the only sense I can make of that requirement.

[3WE]

That's the only sense I can make of that requirement.

I gave up making too much sense of requirements long ago...because it's possible these guys could have taken off with 0/0 visibility...1 mile...1/2 mile.

Terrain, the aircraft, the skill of the pilot...None of that matters, right...

Edit- ATLCrew's knowledge of doesn't hurt anything, of course, and he can certainly get his hand slapped if he messes up.

[Gabriel]

I'm pretty sure single-engine ops allows for known obstacle clearance. If not, I'm taking the train.

It does, but what is the margin in an engine-out situation in a single-engine airplane? Visibility can be helpful there.
Small GA twins are NOT required to have ANY engine-out climb capability. Yow can legally operate a small GA twin in weight / density altitude combinations where the engine-out climb rate at best-climb speed is negative.
Bigger twins have engine-out minimum climb gradient requirements, and so do airplanes with 3 or ore engines, except that the engine-out minimum climb gradient for twins is quite less than for airplanes with 3 or more engines. So again the safety margin is better for airplanes with 3 or more engines.

Isn't the entire point of visibility to be able to detect things that are not known to be there? Otherwise, why do we need it? And isn't the other point of visibility to be able to do something about it, which, at high-speeds on a runway, means being able to stop before hitting them?

No, in aviation that's not the point of visibility, especially not in IMC. There are other provisions to ensure that nothing will be in the active runway except you. When these provisions fail it is called a runway incursion and it is taken as a very serious incident precisely because of the severe potential consequences.

Visibility is supposed to be used to visually fly the plane which in IMC includes being able to track the runway centerline during take-off and landing as well as transition from an instrument approach to a visual landing. Transition from instruments to visual during landing and from visual to instrument in take-off are 2 very critical moments in a flight and different types of disorientation have been responsible for numerous accidents in both cases.

It doesn't seem too beneficial for a pilot to be able to say, "oh, there's the snowplow that isn't supposed to be there, the one we will now plow into." But that is exactly what it comes down to if your minimum visibility is shorter than your stopping distance.

Yep. That's a risk and has caused accidents too. But that's NOT what required visibility minimums are for. Or explain CAT II / CAT III landings.