Oh, that's a fun one...
Let's start by imagining that all electronics and all moving parts on the airplane fail. It's still structurally intact, but there's no way to control the plane.
If this happens, the #1 problem is the spiral dive. The bank angle will steadily increase further and further. As the bank angle increases, the wings are less and less effective at holding the airplane up, so eventually... they stop holding it up.
In order to prevent the bank angle from increasing, the pilots must have some means of lateral control. This means that they must be able to control at least one engine, or at least one aileron, or the rudder.
This other answer states that if an Airbus's electrical system fails, "the system reverts to mechanical backup, where pitch control is achieved through the horizontal stabilizer and lateral control is accomplished using the rudder pedals."
So if you want as many things as possible to go wrong, while still being a survivable failure, I suggest:
- All four engines fail.
- The landing gear fails; it cannot be extended. (If the landing gear could be extended and retracted, the pilots could use it as a flight control.)
- The entire electrical system fails, meaning that conventional control is no longer possible.
- The trimmable horizontal stabilizer also fails, meaning that the only flight control available is the rudder.
If the pilots are sufficiently skilled, they will be able to maintain directional control, and avoid both Dutch roll oscillations and phugoid oscillations when they do. If the pilots are able to do that, then their job description becomes very simple: control the direction of the airplane in such a way that when it touches the ground, it's on a runway.
There's one problem remaining with using the rudder only, and that's that there's no way to control the airplane's descent rate. It'll simply descend at whatever rate it "wants to", aerodynamically. This descent rate may be similar to the descent rate of the so-called Gimli Glider (Air Canada Flight 143, which was a Boeing 767). I don't know what that descent rate was, but a couple of web pages describe it as being about 2,000 feet per minute, which is about 20 miles per hour. Keep in mind, that's 20 miles per hour straight down.
(If the pilots are really skilled, they'll induce a phugoid oscillation which is timed in such a way that the touchdown is gentler. But that sounds pretty unlikely.)
If you want to give your pilots even more of a thrill ride, you can have the rudder fail upon touchdown, or even a few seconds (10 or 20 seconds?) before touchdown. The effect will be pretty much the same as a car: the plane will continue in the same direction for a few seconds, but it'll inevitably start to veer to one side. It will likely run off the runway and into the grass.
All in all, the outcome will probably be exactly what you're looking for: lots and lots of components fail, the plane ends up a "mangled wreck", but everyone survives.
- Even if the landing gear were working perfectly fine, the pilots might decide not to use it. If they extended the gear in flight, but the gear failed to retract, then it would cause drag, resulting in an increased descent rate, which could be disastrous. If they extended the gear just before touchdown, but the brakes failed, then they might overrun the end of the runway; if they ran into an obstacle, that could be even worse than making a gear-up landing.
- As a little bonus, you could have the cockpit voice recorder and the flight data recorder both fail at the very beginning of the flight. This is likely to leave investigators more confused about what could have caused the accident.
- I'm a Dresden fan too; let me know if you finish your story!