Teflon hose life

[Sabremech]

Astelmaszek, 

I understand your personal thoughts on 135, but don't agree with maintaining my Mooney to those rules. Am I any less safe because I maintain my airplane to Part 91? I don't believe so as I maintain the airplane I fly myself and my family in. I don't offer Part 135 advice on this board because it does not apply to 99 % of us who come here to share information.  

For the amount of flying we do, maintaing our airplanes to Part 135 would cost us an extreme amount of money and for what quantified increase in safety? Very little. What percentage of Mooney accidents are caused from maintaining our airplanes to Part 91 vs 135? 

I don't fault you for your choice in the way you maintain your airplane, it's your money and your choice. I'll continue to offer the advice that's relevant to the rules we are required to maintain our airplanes to. Anything above and beyond that an owner wants to do is their choice. 

As far as the examples I quoted, Falcons and F86, they were merely presented to show that Teflon hoses are on condition. No mandatory replacement criteria. It's not even required on a Falcon that is operated under Part 135.

 

[Becca]

Quote: astelmaszek

You got one engine, is your life really that cheap than a $2000 set of new hoses every 7 years is too much? Or a propeller reseal and repaint for another $2K every 6 years? You can't just stop and pull over. Or a third set of eyes during any maintenance.

[tony]

Becca, squirrel answered you guys in the second post.

I would ask the IA to reference the FAR, AD etc that you are in violation of and have your IA sign off the annual with discrepancies. At this point I wouldn’t have him correct anything. Remember a service bulletin is a recommendation not a requirement. Then take the aircraft to your regular mechanic (the one you trust) and have your mechanic return the aircraft to service by correcting the discrepancies.

You could end up with an entry in your log book that says “inspected hoses and no corrective action required at this time, return to service”.

If you feel this IA is unreasonable, you have a whole year to find a new one for next year.

You and Byron are pretty savvy, you know how to read and interpret data. I think you know what reasonable and what’s not. You guys need to remain in charge of the situation not the IA.

 

 

[Sabremech]

Byron is not in violation of any FAR or AD. If his manual says "on condition" then that is it. Inspect the hoses as you would per Mooney service manual and AC 43-13 and press on.

Here's a little hose inspection advice from the www.

 

"PTFE hose assemblies
“On Condition” is a well known argument for the lifetime of PFTE hoses. As a remark, some manufacturer also demand the replacement of PFTE hoses for special applications.

What we can tell you for sure are criterions for damaged hose assemblies.

Criterions for the hose inspection

• 
  
• Inspect hoses frequently
  
• Replace worn or damaged hoses
  
• Proper clamping is critical
  

Hose assemblies have to be replaced if following is applicable

• 
  
• Chafed Hose
  
  • 
    
  • Abrasion
    
  • Improper clamping
    
  
  
  
• Kinked Hose
  
  • 
    
  • Smooth-bore PTFE hose is prone to kinking
    
  • Restricts fluid flow
    
  • Damaged beyond repair
    
  
  
  
• Broken Wires
  
  • 
    
  • Inspect external wire braid
    
  • Any broken wires is cause for removal/scrap
    
  
  
  
• Twisted Hose
  
  • 
    
  • Hose is not designed to be twisted
    
  • Induces stress
    
  • Promotes premature wear
    
  
  
  
• Heat Damaged (Brittle) Hose
  
  • 
    
  • Elastomeric, PTFE and Metal Hose have heat limitations
    
  • Cracks during flexing
    
  
  
  
• Leaking Hose
  
  • 
    
  • Wetness around fitting
    
  • Aged hose
    
  • Improper fitting attachment
    
  
  
  
• Rusted Hose
  
  • 
    
  • Corroded wire braids
    
  • Any corrosion makes hose assembly suspect"
    
  
  
  

I'll make a calll to my PMI tomorrow and see if I can get a reference in an AC or the FAR's to help put this topic to rest.

 David A&P/IA

 

[RETIRED-SOME]

Wow,,,what a lot of conversation on gyro instrument hoses.

[jetdriven]

This is about fuel and oil hoses forward of the firewall. 

 

[Sabremech]

I e-mailed my FAA PMI today this very question and here is the exchange:

  Me":

 So if the aircraft manual states "on condition" and is approved by the FAA, then there isn't a hard change date and it wouldn't need to be changed until it failed hose inspection criteria?

  FAA PMI:

Correct.

As I stated - the Cessna document is what they decided they want for a life
limit.  I think Lear has a 5-year limit on some hoses.  If the Maintenance
Manual says on-condition - then the hoses should be good until they no
longer meet the aircraft's inspection program requirements.  Typically
those requirements are the same as 14 CFR 43 Appendix D(d)(7) & (e)(5) - -
Lines, hoes and clamps - for leaks, improper condition and looseness - - -
and - - - Hydraulic lines - for leakage.

Improper condition could be the result of chaffing or kinks.

 I hope this answers the question Byron? I haven't forgotten about our oil viscosity discussion, just haven't had the time to put thoughts to e-mail.

[jetdriven]

Thanks, David.  I showed this to my IA and he sees how "on conditon" applies to Teflon hoses.  You jsut saved me 900$ and ten hours labor.