Civilian planes don't normally land with snow or ice on the runway, because directional control becomes very risky at low speeds. At landing speed you initially have control via the rudder, but once you're down tot taxi speed you can only steer the small rubber nose wheel which doesn't do much if it has no grip.
Airports are continuously cleared / de-iced in adverse weather conditions. And if things become too bad, flights are cancelled.
Can these planes still land in somewhat icy and snowy weather? The article mentioned drag chutes and arrestor hooks, but I’d imagine a foot of snow being a problem…
edit: sorry, I just realised you were talking of a one off, for this plane. Naturally it'd be fine frozen, but you'd have to wait a bit, until the ground froze a bit. eg, not just the surface. Here that usually takes a month or more, because the ground takes quite some time to cool.
--
The road gets warm in the winter, even at -40C, if there is a lot of traffic. Snow is smushed, it is warmed by the tires, due to friction, and even sublimation happens.
If there is enough traffic, frozen ground can become thawed. Especally at a mere -10C. The dirt road in front of my house confirms this in winter, with potholes and wet spots, and not from salt.
Landing events have even more friction. And many aircraft are far heavier than cars.
Rare teaffic would be fine I guess, but a mildly busy airfield might be different.
Takeoff and landing distances are based on surface conditions, and those conditions have to be known for pilots to make accurate decisions for the type of aircraft they are flying. Presumably unexpected water on the runway (which might later freeze, too) would cause the state to deviate from what was expected.
For a particular plane, there are some runways that are long enough for takeoff when dry, but not (say) safe for takeoff with water/ice because you cannot abort safely.
This is less of a thing for planes flying back and forth between large commercial hubs (since those same aircraft fly every day, in whatever conditions, they are generally sized accordingly). For a military heavy-lift transport, though, this becomes more of a thing.
My dad worked at Galena AFB in Alaska during the Cold War. They had big problems with the runway icing up, and it was pretty much a 24 hour operation keeping the runway free of ice.
One person proposed coating the runway with linseed oil to keep the ice from forming. Desperate, the AF tried it.
It did keep the ice off. However, the first jet that rolled onto the runway and came to a stop, slowly but surely slid off the runway. Then they had an even more expensive operation to remove the oil.
Some traction is needed until the airplane is moving fast enough so the control surfaces work. Otherwise, off the side of the runway you go.
Errr... yes it does. A runway is empty space. There are no other planes on it, it's a straight, well-maintained stretch of pavement, kept clear of ice and snow, with clear markings. Those are conditions so easy that non-self-driving cars can manage to navigate them for non-trivial periods of time without hitting anything! The Mythbusters have had a couple of cars go entirely out of control a couple times under those circumstances and the damage was a fence, once, IIRC.
Ever driven a car through a field? What looks smooth is often anything but, and airliners are simply not designed to take off from unprepared surfaces.
Flattening frozen ground seems significantly more difficult than just laying down panels.
Arguably, taking off along a route where one could potentially be stuck in icing for an extended period, in an aircraft not capable of that, is the definition of poor pre-departure decision making. Commercial airliners have relief to dispatch with malfunctioning anti-ice gear. The procedures almost always dictate that flight in known or forecast icing conditions is prohibited. Basically, if it’s not summer and there’s a cloud in the sky you’re not going. Icing is not something to mess around with in an aircraft not properly equipped for it.
I would speculate that it lands on skids. Skids are pretty lightweight and will do fine for landing, but you need a lot of power to take off with them unless you're on ice or snow.
(You know your landing gear is up when it takes full power to taxi.)
I don't think anything too bad could happen when landing light aircraft on slippery but long runway. I was doing some winter flying and was landing pa28 on slippery runway (compressed snow) and I didn't noticed any difference until i started pressing brakes which had virtually no effect on deceleration. On touchdown you have a lot of aerodynamic authority on your controls so runway friction doesn't really matter unless you have super strong crosswind that could blow you out the runway i guess.
TThough unmentioned in the article, their thoroughness (& the value involved) implies they'll have a fix in place before attempting take-off – perhaps some form of quick/temporary pavement, perhaps assisted by seasonal freezing.
(Might a glassy-ice surface, created with pumped water, under durable winter freeze conditions be ideal? Does a jet need – or even necessarily want – any ground traction to take off?)
"...The presence of snow and ice on runway surfaces reduces the available tire-pavement friction needed for retardation and directional control and causes potential economic and safety threats for the aviation industry during
the winter seasons...
...To activate appropriate safety procedures, pilots need accurate and timely information on the actual runway surface conditions. In this study, XGBoost is used to create a combined runway assessment system, which includes a classification model to predict slippery conditions and a regression model to predict the level of slipperiness. The models are trained on weather data and data from runway reports. The runway surface conditions are represented by the tire-pavement friction coefficient, which is estimated from flight sensor data from landing aircrafts...
...To evaluate the performance of the models, they are compared to several state-of-the-art runway assessment methods. The XGBoost models identify slippery runway conditions with a ROC AUC of 0.95, predict the friction coefficient with a MAE of 0.0254, and outperforms all the previous methods..."
Jets plug these numbers into the flight computer to determine landing speed (Vref), needed runway length, and sometimes configuration (flaps etc.). So without weather I'd expect commercial flights to simply stay on the ground.
Non sequitur from non-pilot: I was once in Duluth, MN in the bitter cold and watched a Cessna with skis (for landing on the frozen lakes of the Boundary Waters) land at the airport. It was the utterly bewildering to see how slowly it was going in the air. And how little distance it took to stop. Short Landing Kit I assume. I've seen ducks and geese come into land on lakes at higher speeds!
Yeah, pilots should know what they're getting into and be aware if it exceeds their experience. I didn't mean it to be an endorsement of unsafe behavior.
If the capabilities of the airframe and the pilots skill are sufficient for the conditions, like if your plane is certified for flight into known icing conditions and you have experience doing so, then it's not a huge risk to fly into these situations.
But if your plane has pneumatic deicing boots that require engine power and your engine quits, you may be in over your head in a hurry if ice starts building up while you're trying to perform an emergency landing.
In that situation it would be nice to be able to just pop the chute.
> Aircraft flight characteristics are extremely sensitive to the slightest amount of surface irregularity, in particular that caused by frost, ice, or snow.
> In most cases ground-based deicing is accomplished by spraying the aircraft with an aircraft deicing fluid just prior to departure. […] Typically deicing fluids are applied using a specialized vehicle similar to a "cherry picker"
Airports are continuously cleared / de-iced in adverse weather conditions. And if things become too bad, flights are cancelled.
reply