'51 C170 Cowl Latch Backup

boydkl · Post by **boydkl** » Mon Jan 26, 2004 8:38 pm

I just found Jeff's post 07/10/02 RE: cowl latch failure & damage, and zero.one.victor's reply which indicates that there have been several means devised to secure the cowl against catastrophic opening.
I just replaced the latch spring on the left front side of my cowl because it would pop open during run up. The other 3 replacements are on order.
I now have a safety wire on the front of each side, just in case.
How have other owners resolved this problem ?
Are there any good (inexpensive) approved solutions ?

Thanks

N73087 · Post by **N73087** » Mon Jan 26, 2004 9:50 pm

I installed the Dip Davis cowl latch replacement STC. About $200 per aircraft instead of $250 per latch. I am very happy with the way they are working.
There are pictures on the C140 forum.
http://www.cessna120-140.org/forum/viewtopic.php?t=361

Mon Jan 26, 2004 11:02 pm

The following 3 examples of cowl latch safetys would cost less that $20

My cowl latches have a AN500A drilled fillister head screw inserted in holes drilled on each side of the latch handle. The holes in the screws are lined up and a AN416-2 cowling saftey pin is inserted through both of them in front of the latch handle. The handle can not pop open because the pin stops it. You may have to drill out the hole on the screws so the saftey pin goes through them. I can't imagine the entire installation taking more than a half hour.

My friend has a variant of this which would take more time to fashion. He has 2 aluminum tabs riveted to each side of the cowl latch recess. Each tab sticks out on each side of the handle in the closed position. A hole is drilled in each tab and a AN416 is placed in the holes in front of the latch handle holding it in place.

I have also seen a hole drilled through the center of the handle and the cowl latch recess behind the handle. A bolt is then inserted through the cowl recess and held in place with a nut. the bolt is left long so it would protrude through the latch handle when it is latched. A hole is then drilled in the bolt and a AN416-1 is place in it holding the latch handle closed.

You can go nuts with Winged cam locks or Dzus fastners which accomplish the same thing.

This may sound silly but as long as you don't make a major alteration to the latch mechanisim or totally replace it with belt buckes a modification such as I described in the first three paragrahs would be a minor alteration. It after all would be in addition to the original latch and only require a log book entry. At least that's how I see it.

I could provide simple drawings of the examples I provided if you need them.

Dave Clark · Post by **Dave Clark** » Mon Jan 26, 2004 11:50 pm

I rebuilt all my latches with new parts from Spruce and they work as designed. Just maintain the latches and they'll work fine. The rest is just a patch thing.

doug8082a · Post by **doug8082a** » Tue Jan 27, 2004 1:42 am

Dave Clark wrote:I rebuilt all my latches with new parts from Spruce and they work as designed. Just maintain the latches and they'll work fine. The rest is just a patch thing.

Ditto. I installed new Latch Lever Clips (p/n 0452111 - the little clips that hold the lever closed) and it made a big difference.

Also make sure that your upper and lower cowlings are properly aligned. If not properly aligned it places stress on the latches and may cause them to pop open. This may seem obvious, but sometimes they don't need to be very far out of alignment for this to have an affect on things.

When reinstalling my cowling I get both cowlings and all the screws installed but leave the screws quite loose. I then latch the cowling and let everything "seat itself" for lack of a better description. Once I've pushed and prodded and got things aligned, then I tighten it all down.

zero.one.victor · Post by **zero.one.victor** » Tue Jan 27, 2004 1:47 am

doug8082a wrote: When reinstalling my cowling I get both cowlings and all the screws installed but leave the screws quite loose. I then latch the cowling and let everything "seat itself" for lack of a better description. Once I've pushed and prodded and got things aligned, then I tighten it all down.

I had a hell of a time the first couple times I removed the cowls from my ragwing,til I figured this out. Works like a charm.

Eric

boydkl · Post by **boydkl** » Tue Jan 27, 2004 4:08 pm

THANKS !! Now I have several options !
I checked the 140 website and am going to go out this weekend and look at a local plane that has the FAA approved Davis permanent solution.
My 3 new clips (not springs) came in today from Spruce and I am going to talk with my A&P about the drilled screws and pin as back up if I replace the clips and keep my original latches.
Thanks for taking the time to respond !

Dave Clark · Post by **Dave Clark** » Tue Jan 27, 2004 5:41 pm

It's not just the springs and clips. You need to examine closely the other parts for wear. You can drill out the pins for overhaul (parts replacement) and use the dies in a brake pad rivet tool to reassemble. When I did this i was amazed to see that ALL the parts to build a complete unit will cost half of the price of an assembled unit. It would take about five minutes to assemble a set.

zero.one.victor · Post by **zero.one.victor** » Wed Jan 28, 2004 1:05 am

boydkl wrote:THANKS !! ................and I am going to talk with my A&P about the drilled screws and pin as back up if I replace the clips and keep my original latches.
Thanks for taking the time to respond !

A friend has the cowl latches on her 120 safetied in a similar fashion,only instead of fillister head screws,she has cotter keys installed on both sides of her latches. Drilled holes,with the cotter keys installed in them with the eyes on the outside of the cowl. Then when the latch is closed,a hitch-pin clip goes thru the cotter-key eyes & across the cowl latch. (hope that description makes sense)
My ragwing has U-shaped aluminum brackets that sstraddle the latch,with hitch-pin clips thru holes in the bracket across the cowl latch. Same arrangement,only different.
A friend had the forward LH cowl latch fail on his ragwing right before his trip to Oshkosh last summer. He didn't let it ruin the trip,but it sure didn't do his cowl any good!

Eric

simatos · Post by **simatos** » Thu Jan 19, 2006 6:09 pm

Does any one have information on the CAMLOC install on the cowl latch levers?? I see the cessna 140 folks have done this but the link above doesn't want to open. Specifically the part number for the CAMLOC would be a great help. Thanks Gary

KMac · Post by **KMac** » Mon Jan 23, 2006 4:38 am

There is information in the C170 Association manual that shows the cam loc installation - I think. My manual is at the hanger so I can't check it. I made that mod to my plane. The concern with mine was that the actual pressure cowel/baffeling had been removed and the exterior cowel then becomes a pressure cowel and supposedly the latches were not designed for that.

Hope that helps.

Kevin

Kim Purcell · Post by **Kim Purcell** » Tue Jan 24, 2006 8:46 am

I also have the camlocks on each of my latches and really like them, they are very low profile. I had the excitement of having the left half of my cowl come open one night about 5 minutes after takeoff, I was sure the whole thing would come off and take something else out with it. It was a long flight back to the runway and after replacing all latches I thought a little extra help was a good idea.

simatos · Post by **simatos** » Wed Jan 25, 2006 5:58 am

The thing with the camlocs is figuring out the grip length but now that you mention it I think recall reading that description/installaton in the 170 assn manual which I hope would have some part number info and details on how long the camlos should be. Seems to me a very positive way to lock the dowl down, thanks for the info, Gary

The International Cessna 170 Association

'51 C170 Cowl Latch Backup

'51 C170 Cowl Latch Backup

RE: Cowl Latch Safety Replies

Re: RE: Cowl Latch Safety Replies