DG 300 landing gear

[PK]

Well I finally done it. After checking that my gear handle was in the
proper position twice prior to landing, shortly after touchdown my
gear collapsed!
The only thing we could think is that the gear handle appeared to be
in the detent when it really was not. Further looking at it one can
actually miss the detent slightly, just before the actual notch and
still have the handle touching the side of the cockpit everything
looking just right. Somehow I guess one needs to lean over, look and
make sure it is in actually engaged, somewhat of a pain.
My question, is there any safety device available out there to prevent
this problem? PeterK

[Marc]

On Feb 5, 9:52*am, PK > wrote:
> Well I finally done it. After checking that my gear handle was in the
> proper position twice prior to landing, shortly after touchdown my
> gear collapsed!
> The only thing we could think is that the gear handle appeared to be
> in the detent when it really was not. Further looking at it one can
> actually miss the detent slightly, just before the actual notch and
> still have the handle touching the side of the cockpit everything
> looking just right. Somehow I guess one needs to lean over, look and
> make sure it is in actually engaged, somewhat of a pain.
> My question, is there any safety device available out there to prevent
> this problem? PeterK

It's been a while since I owned a DG, but I do remember that the notch
in the plate in metal plate is not the actual detent. The detent is
visible if you look through the slot in the plate, and IIRC it
consists of a few rubbber shock absorbing donuts with a metal washer
toward the front. The gear handle is supposed slide in front of the
metal washer when you swing it over to the side wall. Unfortunately,
if one applies side pressure while pushing the handle forward, the
handle can slide into to the notch in the plate while the handle is
still aft of the washer, which leaves you with just some rubber and
the small notch locking it into place. Hit a bump sufficient to
bounce the gear out of the over center position, and it collapses. On
my DG-303, the washer hand an added metal half cylinder guard which
covered the rubber donuts. When all works correctly, the guard
prevents the handle from being pushed to the side wall until it is
forward of the washer. Being an expert at finding flaws in systems,
however, I once managed to apply sufficient side pressure to catch the
aft end of the guard part and bend it such that I couldn't push the
handle farther forward. Using my palm to hold the handle forward as
far as it would go, and making a very smooth landing, avoided
disaster.

Bottom line, make sure you don't apply any outward side force to the
handle until it is solidly in the full forward position. I believe
there is a positive gear locking modification for the 300 detailed in
a non-mandatory SB. It may also be possible to retrofit a functional
equivalent of the 303 metal guard to older 300s...

Marc

[eric keetels[_2_]]

Hi Peter,

Make sure the handle is not 180 deg rotated like this: http://
www.mijnalbum.nl/index.php?m=fto&a=73&id=204195357&key=P6XIKMPX

Eric

On 5 feb, 18:52, PK > wrote:
> Well I finally done it. After checking that my gear handle was in the
> proper position twice prior to landing, shortly after touchdown my
> gear collapsed!
> The only thing we could think is that the gear handle appeared to be
> in the detent when it really was not. Further looking at it one can
> actually miss the detent slightly, just before the actual notch and
> still have the handle touching the side of the cockpit everything
> looking just right. Somehow I guess one needs to lean over, look and
> make sure it is in actually engaged, somewhat of a pain.
> My question, is there any safety device available out there to prevent
> this problem? PeterK

[eric keetels[_2_]]

Hi Peter,

Also make sure the handle is not rotated 180 degrees like this:
http://www.mijnalbum.nl/GroteFoto-P6XIKMPX.jpg

Eric


On 5 feb, 18:52, PK > wrote:
> Well I finally done it. After checking that my gear handle was in the
> proper position twice prior to landing, shortly after touchdown my
> gear collapsed!
> The only thing we could think is that the gear handle appeared to be
> in the detent when it really was not. Further looking at it one can
> actually miss the detent slightly, just before the actual notch and
> still have the handle touching the side of the cockpit everything
> looking just right. Somehow I guess one needs to lean over, look and
> make sure it is in actually engaged, somewhat of a pain.
> My question, is there any safety device available out there to prevent
> this problem? PeterK

[eric keetels[_2_]]

Hi Peter,

Also make sure the handle is not rotated 180 deg, like this:
http://www.mijnalbum.nl/GroteFoto-P6XIKMPX.jpg

Eric

On 5 feb, 18:52, PK > wrote:
> Well I finally done it. After checking that my gear handle was in the
> proper position twice prior to landing, shortly after touchdown my
> gear collapsed!
> The only thing we could think is that the gear handle appeared to be
> in the detent when it really was not. Further looking at it one can
> actually miss the detent slightly, just before the actual notch and
> still have the handle touching the side of the cockpit everything
> looking just right. Somehow I guess one needs to lean over, look and
> make sure it is in actually engaged, somewhat of a pain.
> My question, is there any safety device available out there to prevent
> this problem? PeterK

[Larry Suter]

On Feb 5, 4:30*pm, eric keetels > wrote:
> Hi Peter,
>
> Also make sure the handle is not rotated 180 degrees like this:http://www..mijnalbum.nl/GroteFoto-P6XIKMPX.jpg
>
> Eric
>
> On 5 feb, 18:52, PK > wrote:
>
>
>
>
>
When I got my DG-300, another owner suggested getting a cheap, rubber
door-stop from Home Depot and wedge it between the handle and the
inboard side of the slot as a safety.

So far, so good.

Larry


>
>
> > Well I finally done it. After checking that my gear handle was in the
> > proper position twice prior to landing, shortly after touchdown my
> > gear collapsed!
> > The only thing we could think is that the gear handle appeared to be
> > in the detent when it really was not. Further looking at it one can
> > actually miss the detent slightly, just before the actual notch and
> > still have the handle touching the side of the cockpit everything
> > looking just right. Somehow I guess one needs to lean over, look and
> > make sure it is in actually engaged, somewhat of a pain.
> > My question, is there any safety device available out there to prevent
> > this problem? PeterK

[Marc]

On Feb 5, 5:41*pm, Larry Suter > wrote:
> When I got my DG-300, another owner suggested getting a cheap, rubber
> door-stop from Home Depot and wedge it between the handle and the
> inboard side of the slot as a safety.

I know of one pilot who destroyed his glider after he realized on the
turn the final that his gear was up, and had his head down fiddling
with a similar "safety", rather than up looking out for obstacles. It
isn't necessary. Over 25 years I've had close to 500 flights in
various DG-101, 300, 303, and 600, all of which have reputations for
gear collapses, and never had a single collapse. The key is in
understanding how the gear mechanism works, and pushing the handle is
fully forward against the stop, before pushing it over against the
side wall.

And, if I'm not mixing this up with some other gliders I owned, there
is a gas cylinder in the mechanism that is intended to help hold the
gear in the over lock position, after some number of years this
cylinder loses pressure. A simple pull test on the locking strut once
a year is enough to determine that it is still working correctly...

Marc

[PK]

On Feb 5, 7:30*pm, Marc > wrote:
> On Feb 5, 5:41*pm, Larry Suter > wrote:
>
> > When I got my DG-300, another owner suggested getting a cheap, rubber
> > door-stop from Home Depot and wedge it between the handle and the
> > inboard side of the slot as a safety.
>
> I know of one pilot who destroyed his glider after he realized on the
> turn the final that his gear was up, and had his head down fiddling
> with a similar "safety", rather than up looking out for obstacles. *It
> isn't necessary. *Over 25 years I've had close to 500 flights in
> various DG-101, 300, 303, and 600, all of which have reputations for
> gear collapses, and never had a single collapse. *The key is in
> understanding how the gear mechanism works, and pushing the handle is
> fully forward against the stop, before pushing it over against the
> side wall.
>
> And, if I'm not mixing this up with some other gliders I owned, there
> is a gas cylinder in the mechanism that is intended to help hold the
> gear in the over lock position, after some number of years this
> cylinder loses pressure. *A simple pull test on the locking strut once
> a year is enough to determine that it is still working correctly...
>
> Marc

Thank you all for the good advise. PeterK

[Darryl Ramm]

Marc has it well covered. Some extra comments form a previous DG-303 owner....

Your glider should have had the U/C handle mod per TN 359/22. Its a coil spring installed at the handle that helps hold the handle against the side wall. Its very simple to install. When I was shopping for a DG-300/303 years go it was surprising how many 300/303 had not had this mod done, including on gliders that had gear collapses and had been repaired and owners were still unaware of the mod (how can somebody sign off an annual/condition inspection without reviewing all the possible A/D and at least noting this?).

The gear handle "positive" detent lock is a poor design of a small rubber block with a metal shim/cover over it with a locking dimple on it. The rubber block seems to harden/shrink as it ages and becomes less effective. So that rubber block is also something to check at each annual and maybe replace..

There has been past discussion on r.a.s. about checking the U/C locking gas strut, but I could not quickly find the ones I was thinking of that had much detail. Your A&P should have been checking this at each annual. Beyond pilots just forgetting to put the gear down I suspect problems with this gas strut are the number one cause of failures in these now aging gliders, and more important than the points above (but yes do those as well).

Darryl

[brianDG303[_2_]]

On Feb 5, 8:08*pm, Darryl Ramm > wrote:
> Marc has it well covered. Some extra comments form a previous DG-303 owner...
>
> Your glider should have had the U/C handle mod per TN 359/22. Its a coil spring installed at the handle that helps hold the handle against the side wall. Its very simple to install. When I was shopping for a DG-300/303 years go it was surprising how many 300/303 had not had this mod done, including on gliders that had gear collapses and had been repaired and owners were still unaware of the mod (how can somebody sign off an annual/condition inspection without reviewing all the possible A/D and at least noting this?).
>
> The gear handle "positive" detent lock is a poor design of a small rubber block with a metal shim/cover over it with a locking dimple on it. The rubber block seems to harden/shrink as it ages and becomes less effective. So that rubber block is also something to check at each annual and maybe replace.
>
> There has been past discussion on r.a.s. about checking the U/C locking gas strut, but I could not quickly find the ones I was thinking of that had much detail. *Your A&P should have been checking this at each annual. Beyond pilots just forgetting to put the gear down I suspect problems with this gas strut *are the number one cause of failures in these now aging gliders, and more important than the points above (but yes do those as well).
>
> Darryl

I have the mod in my 303, and also swapped in a new U/C gas strut, but
still managed to almost have a gear-up when I got distracted during a
landing, got sloppy about putting the gear down and just sort of
shoved it into the slot without making sure it was fully home.
Generally after the gear is down by habit I put my hand on the gear
handle and make sure it is in contact with the fuselage. What saved
me was the gear warning buzzer, because even with the spring pushing
the handle closed it had not fully engaged.