Lift Strut Punch Test

[Bobdog]

I'm just about ready to paint my struts, but would like to do the "Punch Test" on them first. Does any one have a copy of the Piper service bulletin that tells how to do this? I believe it calls for a Maule fabric tester, but how hard do you push? Thanks, Bob

[high time cub]

Re: Lift Strut Punch Test

Hi Bob, Try this....

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/9F806811E7FDF742862569AC005E0493?OpenDocument

Jim

[Garry Crookham]

Re: Lift Strut Punch Test

Bob,

I think this is what you're looking for:

SUMMARY: (Cont.)



SKETCH "A"

SKETCH "A" INSTRUCTIONS

1. Securely tape a sheet of thin 1/4 inch graph paper to the lower 11 inches of the top and bottom surfaces on all wing lift struts.

2. Using a Maule "Fabric Tester" and holding tool normal to strut contour, apply pressure at a scale reading of 80 in each of the grid blocks.

3. Remove the paper and inspect the lift strut tubes. A perceptible dent will appear if internal corrosion is present. If any dents are found, be certain the dents are in the metal by carefully removing the paint.


a. Lift strut tubes indicating the presence of any perceptible dent in the metal must be replaced with new lift strut assembly before further flight.

b. If no dents appear in the metal, the lift strut may be considered airworthy.

NOTE: Further internal corrosion may be impeded per the following procedure:




a. Remove lift strut from aircraft.

b. Inject one quart of Valoil, Lionoil Multi-Purpose L-1, Linseed Oil, Paralketone or any alternate preservative conforming to Federal Specification TT-S-176D, into the bolt hole at the top of the strut.

c. Plug the bolt holes and slosh oil until interior of strut is thoroughly coated.

d. Drain oil from strut (through bolt holes) and install MS51861-44 sheet metal screw, as shown, for future identification.

e. Reinstall strut to aircraft and rig.
4. Record lift strut inspection in aircraft logbook.


Garry Crookham
N5112M
Tulsa

[Bobdog]

Re: Lift Strut Punch Test

OUTSTANDING!! Gary. This is exactly what I was looking for. I looked up the ADs but they all went with ultasonic testing. I've got a pretty good tool box, but I don't have a ultrasonic tester.

Thanks again, Bob

[wlas]

Re: Lift Strut Punch Test

The punch test is a joke, I never use that method on cubs. We have them X-rayed, the X-ray guy comes out and does it right on the plane or I can take them to him. with X-ray he tell me if theres any pitting inside. now days most guys have life time struts on cubs, but a few still have the old type and its every two years for X-ray. The T-craft struts, at least the old ones are heavier wall thickness than cubs. I had my T-craft struts X-rayed before I had them powder coated.