On Wednesday, March 7, 2018 at 10:32:59 AM UTC-5, wrote:
On Tuesday, March 6, 2018 at 11:46:11 AM UTC-7, Dan Daly wrote:
On Tuesday, March 6, 2018 at 10:55:02 AM UTC-5, Roy B. wrote:
On the subject of Pawnee landing gear - be very careful of the Hutch conversion 2 piece slab type gear that is fixed with 3 vertical bolts. If the centermost bolt fails (as it can from vibration over the years) the gear collapses, the prop strikes the ground, and you have a totaled plane from a situation that really can't be detected/inspected before the failure. We lost a towplane that way in a very light landing on grass when the bolt snapped.
The bungee system has some redundancy and the Cessna one piece gear slab is good - but the 2 piece Hutch gear is a problem.
ROY

The PA-25 SB 25/32/04 dated 01/03/2008 describes a Main Landing Gear Shock Absorption System modification adding a cable to restrict lateral movement of the landing gear leg should a piece of the Hydrasorb shock absorber crack and fail (which they do). We had a Pawnee mod'd (bungee gear system) and had the failure of one support on landing. The down wingtip didn't touch, and neither did the prop. Laviasa had a kit (KIT LA-K-005) with support fittings, a security cable, and longer bolts. Money well spent. I have a soft copy of the SB (2 pages text, 3 pages drawings) if anyone wants one. Also pics of the cable having done its job, a closeup of the installation, and a pic of an unluckier Pawnee without the mod kit.

For light reading, I attach a link to a Canadian Civil Aviation Safety Alert showing the fatigue cracking of the part. https://www.tc.gc.ca/eng/civilaviati...11-02-1344.htm

Dan

Dan, thanks for sharing this information. I'd be very interested in the LAVIASA Service Bulletin kit information. LAVIASA has been very difficult to get ahold of. How can I get in touch?

And for those operating Piper PA-18 Supercubs, F. Atlee Dodge has an STC'd mail landing gear safety cable kit, which is very widely used by "off field" operators, e.g., in Alaska, viz: http://www.fadodge.com/safety-cables-for-mlg-std/

I've been of the opinion that the MLG bolts should be changed out, and attach points closely inspected based on number of landing cycles, rather than just hours, especially for tow operations.

Thanks. Curt

Laviasa is out of business. I'll send the SB etc. The drawings should allow you to re-create it; perhaps Johnson aircraft might be able to help. http://www.johnstonaircraft.com/

Dan