Intentional Gear-Up Landings

In a DG-200 Manual it says:

3. Emergency Procedures

3.4 Landing with the gear retracted

Even on soft field the DG-200 can be landed with then landing gear extended. With the stick pulled back during roll out there is no danger of nosing over. Only in the case of an extremely short landing field should the pilot choose to land wheel up.

After a gear up landing the tow release and cable deflectors should be checked for damage....

1. In what cases would you stop better with the gear up?

*Possibly* in a very short field. A difficult call. My experience is that without the U/C you are just a passenger after touchdown so the groundloop option is removed. If the only field available was that short I might consider other thing first like going between tree trunks or something. I'd also be a little upset at myself for getting into a situation where I was down to those options!

2. Is there any successful history of using this emergency procedure?

I landed intentionally wheel up in a very soft, dark loamy potato field that had been *very* deeply ploughed. I reckoned putting it onto the belly along a furrow would be less dangerous than leaving the wheel out. The field was immense! The landing was spectacularly short, I stopped in about 20 metres. Even without the wheel the single grob stood up high on the forebelly, at perhaps 20 degrees. The retrieve was a mission and we recovered half a bag of potatos from the U/C well. The doors shed almost immediately on touchdown.

3. Is this still endorsed in any modern/current production glider manual?

I'm not sure but it's unlikely, the structure of the U/C will absorb a lot of energy in a *controlled crash* or against a hidden rock.

4. How far do most unintentional gear up landings slide on grass, and pavement?

Mine,in an ASW20bl, on dry grass seemed to go on forever, especially with the crowd standing around watching it! In reality I doubt whether I managed more than 50 or so metres. Right up to the point of touchdown it was a real greaser too. Stopped fully under control, in a straight line. If anything it could not be turned. Wing did not settle to the ground. Onlookers strolled onto runway, grinning, lifted me and glider so that I could extend gear then demanded beer in the pub.

Tarmac and concrete result in longer slides with new white lines laid on the runway surface

All three surfaces are accompanied by the distinct smell of overheated thermoplastics!

tango4

Can't speak from experience *YET* but the CFI is very clear in his view on one time you should land with the wheel up.

When you have a vertical retraction system like on my Cirrus, and you are going to land on a very hard and rough field. (standard field in many parts of South Africa.)

Reasoning presented is that the probability of the U/C mount failing and rotating around the front hinge into the seat pan is high enough to warrant guaranteed damage to the belly.

Any views?

I've not seen a broke undercarrage do than. Usually they fail backwards and upwards and in doing so absorbe alot of energy. If you land wheel up then there are only 2 thin layers of structure and 25mm between you and the ground, rocks etc. I'll go for wheels down every time.

Basil

In that case, you'll have the choice between the stones coming through the belly, and the gear collapsing the way you describe.

I would never, ever intentionally land gear up.

I agree, I can't see any situation where landing gear up should be prefered. The case of a very short field should be better with the gear down, unless you have a very unefficient wheel brake: the wheel against the ground has a higher friction coefficient than the belly. If your wheel brake is powerful enough to bring the nose down, the you have the friction of the wheel plus the nose instead of the belly only.

A friend of mine landed a Ventus-CT, with a rough running engine which couldnt be shut down, with the wheel up.

Unfortunately, he admitted he didnt do this on purpose and that he simply got maxed out by what was happening. Shame really, we all thought this was excellent thinking by someone who was obviously under a lot of pressure!

On a side issue, may just be worth pointing out to some newer people here that it is much better to land wheels up than crash trying to put the wheel down at low level when you have forgotten to do it earlier.

At 10:42 22 October 2002, Robert Ehrlich wrote:

Having personally conducted destructive testing of one landing gear assembly (:-O , my strong opinion is that having the energy absorbed by the gear and related structure (no matter what the failure mode or configuration) is far preferable to relying on the bottom surfaces (glider's or pilot's). Agree with another poster that the primary loads are longitudinal, such that failure results in the gear rotating up and back; I'd find it hard to believe that the Cirrus attach points would be strong enough in shear and tension to allow the whole unit to rotate around them and into the cockpit. But, I'm sure somebody out there at a repair facility has some actual experience with that ship.

Approximately2 - 3 months ago, a pilot in So. California encountered tremendous sink as he was coming back to the gliderport. No time for a pattern, however short. His solution: he came ACROSS the field at zero altitude, and landed deliberately wheel up. By the time he had slowed down sufficiently he ground looped also deliberately to avoid parked gliders. Damage to the glider: minimal. To his pride: maximum. From discussions with witnesses, it turned out his actions were the correct ones, except for one: letting himself get so low.

Cheers, Charles

Would it be best to land gear up in a soft field if you were flying an older out of production sailplane with a known weak gear design? I think of retractable Austria and Phoebus sailplanes for example. It will suffer damage to the belly ,however it may be more easily repaired than trying to locate another gear assembly.

Which I think nicely proves the argument for CSL.

Many years, many years ago, in a boardroom far, far away... I was quizzed in a meeting about what design methodology we were using to design this rather complex computer system. This person was expecting us to quote some or other formal design methodology and throw buzzwords like JAD, RAD and whatever around. My answer was very simple and to the point - we were using CSL.

Three months later at the next <insert long name here> meeting, this person asked me what was CSL. She had researched, read the literature, ask the experts, but could not find any reference to a methodology called CSL.

I looked surprised (or at least I tried to fake it). It is simply an acronym for 'Common Sense and Logic' I told the person.

Whether shit hits the fan, or you designing complex computer systems, just use common sense and with some logic.

Sticking to these Absolute Rules like 'Thou shalt never land gear up' or 'Thou shalt not use multiple exits in a code block', make nice epitaphs.