jason219 writes:

Three hours into the flight, one of our planes was involved in a mid-air
collision (whether it was with another aircraft or another object, I am
not sure). The plane is still airborne but is only able to fly higher
and to the right. All attempts to make a left turn or decrease altitude
have failed.

I need some expert knowledge on what would happen in this situation.
Judging by the damage, is it possible to land the plane safely? Is an
emergency landing feasible? If so, what would the steps necessary be to
execute it and how long (roughly) would that take?

First, it's never impossible to decrease altitude. All you have to do is
reduce power, and you descend. If for some reason you cannot adjust the
control surfaces at all, and cannot control the engines at all, you'll still
descend once you run out of fuel. So that part isn't very realistic.

As for being able to turn right but not left, that would require an extremely
unusual set of circumstances, since the same control surfaces are used for
turns in both directions. And since a turn begins by rolling the aircraft, an
inability to roll it in the opposite direction would make it impossible to end
the turn in most cases, and ultimately bad things would happen.

But let's assume that both types of damage are possible. In that case, the
airplane can never land, since it cannot descend. Let's suppose that it finds
a way to descend, then. If it still only only turn right, it might be able to
find its way down to an airport. It could work its way down with just right
turns, but the final approach would be extremely difficult, since only
corrections to the right would be possible, and any circumstance that might
require turning left (such as maintaining alignment with the runway) would
require starting over with the approach. This does not bode well for a safe
landing, unless the aircraft has expert pilots and unlimited fuel aboard.

It might be better to select a different type of damage. The loss of all
controls except engines has already happened, for example. See United Airlines
Flight 232 (most of the people aboard survived) and JAL Flight 123 (all but
four of the 524 people aboard the aircraft died).