Other Rotax Rubber Hose Replacements

[airhound]

Was wondering if there are other than Rotax engines made for aircraft, if so, do they have the 5 year hose replacement requirement?

[Anticept]

AD 95-26-33

The above AD requires 8 years as one of its conditions.

Recommendations from manufacturer to manufacturer vary, but I find 6-8 years common once in service. Shelf life before service can be another few years. I was kind of surprised when I first heard about 5 year replacements with Rotax because that is really short, but when you compare a proper aviation hose next to the hoses we use on our aircraft, you might understand why there is a difference.

Generally speaking, hoses in hot zones decay quickly. We also have hoses exposed to ethanol, which is a VERY STONG solvent. Even with resistant hoses, it wins out eventually against most, if not all, rubbers.

Hoses that have more solid end connectors, like AN fittings, and coatings to protect fron heat tend to last a very, very long time. Really though, the best option for very long term life would be PTFE (teflon) hoses, if they were not so incredibly expensive.

[Roger Lee]

AD's are usually for certified aircraft and SD's are for LSA. Plus a company like Rotax can not set the requirements over and above or under what the FAA regulates in the US.

[Anticept]

I don't mean to imply the AD is for our aircraft, it applies to certain piper models, just answering the question of "are there other engines...?"

[Tom Baker]

4 hours ago, Roger Lee said:

AD's are usually for certified aircraft and SD's are for LSA. Plus a company like Rotax can not set the requirements over and above or under what the FAA regulates in the US.

Except for equipment installed on LSA like the Ameri King ELT that many of the early CT's had.

 

[Tom Baker]

To further expand on what Corey said. The Piper AD came out originally in 1995. Some of the Cherokee fleet was over 30 years old at that point. Piper makes a recommendation to replace the oil cooler hoses at 8 years or 1000 hours, but the standard in GA is to inspect on condition. Many of those 30 year old airplanes had never had the hoses replaced, as mechanics had deemed them safe based on appearance. Obviously the condition of some of these hoses were not safe, because there were several aircraft fires from failed hoses. The FAA took the judgement out of the mechanics hands and made replacement mandatory. 

Like Piper, Beechcraft also has hose replacement recommendations based on calendar and time in service. I suspect Cessna has the same. So how old is to old? The hoses don't come with an expiration date, so you have two choices. First is replace them when they fail. This way you get all of the useful life from the hose. The down side is the hose failure could cause catastrophic failure of the engine, and or loss of life. The second choice is to replace them on a schedule before they fail, and give up useful life of the hose. I'm certain that Rotax's schedule for replacement is very conservative, and certainly can be extended. Who knows how far it can be extended before you get to the expiration date? 

Visual inspection of the hose doesn't give you the complete picture either. I experienced a loss of power just after take off in a Piper Tri Pacer due to a failed hose. It looked fine on the outside, but the inside was shriveled up like a sphincter. 

[airhound]

Believe the foregoing, Rubber Hose, Big-Picture, professionally steeped, discussion, has helped me be a better…ahhhh better……….Rubber Hose Owner/Operator .  Thank You!