Stopping a light twin on sheet ice
Sub Judice Angel Lovegod
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Stopping a light twin on sheet ice
I am about to set off for the deep Arctic in my Aztec and will be visiting some places where, although there are runways, they will be covered in sheet ice at this time of year, so I need to perfect my technique for stopping with nil surface friction.
Obviously (at least I hope it is obvious) I shall land with full flap, fully held off, as slowly as possible, I will then keep the nose as high as possible for as long as possible to get the maximum aerodynamic braking.
My question is, once all three wheels are on the ground should I leave the flaps down for maximum aerodynamic braking, or should I raise the flaps to reduce lift and therefore get more weight on the wheels?
(The flap lever is far enough from the gear lever to make confusion unlikely)
Obviously (at least I hope it is obvious) I shall land with full flap, fully held off, as slowly as possible, I will then keep the nose as high as possible for as long as possible to get the maximum aerodynamic braking.
My question is, once all three wheels are on the ground should I leave the flaps down for maximum aerodynamic braking, or should I raise the flaps to reduce lift and therefore get more weight on the wheels?
(The flap lever is far enough from the gear lever to make confusion unlikely)
I don't have any data to hand, but I'm pretty certain that I've seen some published handling and performance data from Transport Canada concerning landings on ice - after all, they should understand the stuff better than most. It might be worth inquiring in that direction.
Good luck,
G
Good luck,
G
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The exact procedure will be aircraft specific - if there is nothing in your aircraft flight manual about landing on ice, then follow the procedure for landing on contaminated runways or the procedure in the event of hydroplaning on landing.
If still nothing in your flight manual, then presuming that your LDA is non-limitative I suggest you dump the flaps to try give your main landing gear as much grip as possible. I am not talking about grip for braking (I presume you won't even be thinking of touching the brakes!) but for lateral grip. Also, you could try keeping the CG as forward as possible (within the normal CG limits) so as to maximise your directional stability on the landing roll.
If still nothing in your flight manual, then presuming that your LDA is non-limitative I suggest you dump the flaps to try give your main landing gear as much grip as possible. I am not talking about grip for braking (I presume you won't even be thinking of touching the brakes!) but for lateral grip. Also, you could try keeping the CG as forward as possible (within the normal CG limits) so as to maximise your directional stability on the landing roll.
Sub Judice Angel Lovegod
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The LDA will be an issue, which is why I am thinking this through. I will have about 900m minimum, which is oodles under normal circumstances but which may or may not be an issue if it is literally a skating rink.
The CofG is an interesting dimension. Generally we will want an aft CofG for the cruise for efficiency purposes (there are going to be some very long legs with very extended diversions), so I was thinking of going to the back of the envelope for T/O and landing, then moving stuff backwards in flight in order to be as aft as possible to reduce tailplane drag. Also, the Aztec can be quite determined to drop its nose wheel on landing, with a forward CofG, even with the stick right back. However, I had not considered the effect of the aft CofG on stability on the ground, particularly as there will be no choice of landing direction, so weathercocking becomes an issue. I guess I could hold off as long as possible, then, when I lose authority, push forwards and raise flap to get weight on the nosewheel. It's all a bit complex.
The CofG is an interesting dimension. Generally we will want an aft CofG for the cruise for efficiency purposes (there are going to be some very long legs with very extended diversions), so I was thinking of going to the back of the envelope for T/O and landing, then moving stuff backwards in flight in order to be as aft as possible to reduce tailplane drag. Also, the Aztec can be quite determined to drop its nose wheel on landing, with a forward CofG, even with the stick right back. However, I had not considered the effect of the aft CofG on stability on the ground, particularly as there will be no choice of landing direction, so weathercocking becomes an issue. I guess I could hold off as long as possible, then, when I lose authority, push forwards and raise flap to get weight on the nosewheel. It's all a bit complex.
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[SIZE="4"]"I was thinking of going to the back of the envelope for T/O and landing, then moving stuff backwards in flight[/SIZE]"
Please beware that operating an aircraft outside of the cleared C of G envelope at ANY stage of flight will affect longitudinal stability and could result in loss of control!
Please beware that operating an aircraft outside of the cleared C of G envelope at ANY stage of flight will affect longitudinal stability and could result in loss of control!
