lml@lancaironline.net Mailing List Archive

I'd suggest looking at http://www.sacskyranch.com/h_life.htm . Sky Ranch also sells the "Mechanic's Toolbox" program which has a wealth of information on aircraft components, including additional photos of failed hoses.

Are the hoses stiff? Do you feel them crackle or creak as you bend them? If the exterior coating is breaking off that may be the case. You didn't say what type of hose was used, but if they exhibit those symptoms I was taught to replace them. If you're in doubt the best thing would be to have an A&P look at them.

Another consideration is the inner liner. It may be deteriorating also. The hoses on my Navion were old but didn't show exterior deterioration such as you describe. When I replaced them the hydraulic fluid was black with small particles despite the fact that the system has a substantial filter. Once new hoses were in place the fluid has stayed clear. My conclusion is the inside of the hoses was sloughing off. -Bill Wade

----- Original Message -----

From: George and Shirley Shattuck

To: lml@lancaironline.net

Sent: Wednesday, October 20, 2010 3:36 PM

Subject: [LML] Hydraulic hoses

Very timely, for me, are recent postings regarding hydraulic hoses.

After 16 years, the outer rubber coating on my hoses is starting to crack and, on many of my hoses, is actually breaking off, revealing the white woven material. I have been watching this occur with some concern.

The question is: Is this an immediate safety concern? Is there increased chances of a hose failure, and if so, how big a concern is it. In other words, should the airplane be immediately grounded until I fabricate new hoses?

These questions are for an experienced hydraulics person, and not for emotional speculation by those seeking perfection.

George Shattuck

LNC2, 1350 flight hours