FAA response to Rotax 5 yr 'Mandatory' hose replacement..

[Anticept]

Doug, I appreciate your dilemma as a service guy.  But as an owner, it is my responsibility to make sure the aircraft I own and the log books associated with it are not just meeting the letter of the law, but reflect an eager willingness to do all that seems possible to ensure the safety of myself and anyone else I may take flying with me on a given day.

 

 

Doug is making the point, that it's up to you to figure out how many pennies you want to put down. He's also making the point that some maintenance is done unnecessarily, and if it IS necessary for safety, then service bulletins are not enough, they should be in the form of Safety Directives.

 

We all have a different line drawn in the sand for safety vs cost. One could argue that cost should not be an option when it comes to safety, but then I would ask "what is safe, then?" Everything we do carries risk. That's why there is an entire industry dedicated to risk management, the chief of which is known as insurance.

[Doug Hereford]

100hamburger,

I agree, the manufacturer should not issue a Safety Directive for every nut and bolt. That is not the intent of the system. By law however, they (aircraft mfg) must monitor for, and correct unsafe conditions on their product........to include engines, avionics and all other pieces that make up the AIRCRAFT. In the SLSA world, this is required to be done using the Safety Directive system. Everyone should expect them to do that! In a sense, it is also a part of what one pays for when they purchase an SLSA aircraft. FD gladly took your money didn't they?

 

Whether you want to believe it or not, the FARs are in place for safety. Moreover, where this discussion is concerned, if FAR 91.327 where actually interpreted as I understand Sword Guy's position to be, then you might as well change your name to 10000000000hamburger. The manufacturer would have the force and effect of law to impose any requirements they see fit as long as they refer to them as "Maintenance and Inspection procedures".

 

None of my opinions are meant to suggest that we should "ignore" manufacturers recommendations. Just that we do not have to, and should not blindly accept everything they say as the end-all, be-all solution. I personally believe that they are the experts on "manufacturing" their products. They may or may not be the experts on maintaining them. Either way, it is yours and my butts on the line, not theirs. I like the phrase "Trust, but verify".

Fortunately for all of us, the FAR's don't trust anyone, including manufacturers.

 

Doug Hereford

[FlyingMonkey]

The hose change requirement is not in place for safety.  It is in place for liability.  In this case, there is a small chance that at *some* age a deteriorating hose could cause debris to get into various engine areas (like the carbs) causing problems in flight.  Therefore Rotax picked some arbitrary and likely overly-conservative service interval to avoid the liability problem and to be able to claim that due diligence was done.

 

Essentially, Rotax has shifted liability for hose issues from themselves to the owner/operators and mechanics.  The hoses are probably good for ten years, so Rotax picks an interval of five years... an interval so short that hose problems are almost impossible in that span.  If the hose fails it will almost certainly do so beyond the five year interval, and Rotax can simply say that any failure is due to either a) ignoring their recommended interval, Improper technique in hose change, or c) defective or out-of-spec hoses used in the hose change.  In all three cases, liability rests outside of Rotax.

 

I don't fault Rotax for this, it's a wise policy to limit liability exposure.  But it's also a wise policy for owners to avoid maintenance induced failures by not doing work more often than required by technical considerations.  Changing oil every ten hours would add more risk of failure than it would alleviate.  It's unclear if this hose change interval falls in that category. 

[Roger Lee]

Liability, testing, experience and stupid people paves the way for a number drawn in the sand. You have to put it some where and many times to protect the public from itself. Personally I don't have a problem if someone wants to kill themself, but it usually involves others that don't get to make that choice or rely on us not to get them hurt and of course when something happens it's everyone else's fault.

 

It isn't arbitrairy number. Gates and the other hose MFG's found that starting at 4 years of age hose incidents climbed dramatically and every year after that it continued to climb with a rapid rate. These numbers and test is public knowledge on their websites. Does hose last longer no doubt, but if they said change hose at 8 years and people had hose failures in aircraft that caused death or serious injury then just 1-2 litigations could be financially devastating. Look in your car Maint. Manual and see when it recommends hose and belt changes. Usually 3-5 years. If we in aviation had as many belt and hose failures as autos in the US we would have a lot more pilots landing in fields.

 

When I was a paramedic you didn't try to see how far or what you could get away with. You stepped up to the plate and did one better if in doubt. Lazy medics can and do cause additional injuries and death. You might argue that I had someone on the floor at that moment and their life in my hands, but your life is in your hands while flying. Since someone isn't on the floor dying while your flying and things are going good we never seem to see ourselves or a family member lying on the floor dying at that moment in time.

Here's the problem with people.

 

We never see an emergency coming and some don't care about an emergency until it happens because everything the moment before is going good. When an emergency happens it is everyone else's fault.

Public safety is about pro-active prevention and not reaction trying to fix people's mistakes. Hence we have rules, regs. and laws to protect us and others from us.

There is no glory in saving yourself or someone else from being stupid if it could have been prevented.

 

30 years of public service saving people from themselves has made me a cynic to say the least. It makes you wonder sometimes how people get through life.

[FlyingMonkey]

I don't disagree with anything Roger has said.  The goal here is neither to try to do minimum maintenance nor to "get away" with anything or save money.  But every maintenance decision is a balance of risk v. reward.  It might increase safety, but just the act of touching a functioning system introduces risk.  Look what happened to CT...did the recommended maintenance, and as a result had an engine loss of power that would have been avoided if he'd left it alone.

 

Once again, I'm planning to do the rubber replacement as recommended when it comes up again and am NOT suggesting skipping or deferring it.  But every owner should look at all maintenance with a jaundiced eye and think long and hard about the risks involved, and not blindly doing every single maintenance item slavishly and without reflection.

[Ed Cesnalis]

I've recently had another new rubber line fail.  It failed mid span where there is no hard sharp object that could have caused the puncture.  I assume it is one more failure created at the time of replacement and took a while to turn into a difficult to locate coolant leak.  The potential for damage is there, overheating occurred rapidly.

[Jim Meade]

This entire thread is an interesting example of how what people see depends on where they stand. And isn't it interesting that many strongly presented opinions are only the presenters words without a shred of substantiating documentation or even a reference.

 

Much of aircraft maintenance is this way - it's the way the old school A&Ps operated for a century. I had hoped that LSA would introduce new, fresh air into aviation maintenance but I fail to see much.

 

Let me make an observation. As one browses other forums such as Vans Air Force, Kitfox, the several Rans forums and more, one sees different cultures about aviation maintenance. The builder fellows seem to me to be more open to various solutions, less acceptant of "because I say so", and more likely to offer various alternatives to challenges.

 

It would be nice if one could see the data behind the decisions on hose lifetime choices. I'd like to see what Rotax used as a basis for their decisions. I'd like to see what Gates says about hose life. In many engineering fields, one can find hard data on materials specifications. Why should we have to guess about what the numbers say on a hose? Why is the information not presented? So some company can claim proprietary rights to information that may have health and welfare affects on my passengers and me?

[Ed Cesnalis]

Here's an EAA doc on Reliability-Centered Maintenance (RCM)

 

http://eaa393.org/Presentations/Short_RCM-CondMon-MxMangement.pdf

 

Q: How can doing LESS maintenance result in

MORE safety and reliability?

A: By reducing MIFs (Maintenance-induced failures)

[Anticept]

This entire thread is an interesting example of how what people see depends on where they stand. And isn't it interesting that many strongly presented opinions are only the presenters words without a shred of substantiating documentation or even a reference.

 

Much of aircraft maintenance is this way - it's the way the old school A&Ps operated for a century. I had hoped that LSA would introduce new, fresh air into aviation maintenance but I fail to see much.

 

Let me make an observation. As one browses other forums such as Vans Air Force, Kitfox, the several Rans forums and more, one sees different cultures about aviation maintenance. The builder fellows seem to me to be more open to various solutions, less acceptant of "because I say so", and more likely to offer various alternatives to challenges.

 

It would be nice if one could see the data behind the decisions on hose lifetime choices. I'd like to see what Rotax used as a basis for their decisions. I'd like to see what Gates says about hose life. In many engineering fields, one can find hard data on materials specifications. Why should we have to guess about what the numbers say on a hose? Why is the information not presented? So some company can claim proprietary rights to information that may have health and welfare affects on my passengers and me?

 

A lot of this has to do with the fact that the builder has more freedom to choose what they use, while an A&P can be ruined by one mistake. I would be much more flexible with my maintenance options if I didn't have to worry about a single lawsuit ruining everything I've built, or the FAA going regs crazy. On the flip side, I understand why the liability is there, it generally keeps people on the straight and narrow. Anyways, builders also know their aircraft intimately, whereas mechanics can see considerable variations between two aircraft that are one serial number apart.

 

Many years ago, A&Ps actually were much more free to maintain aircraft and make decisions on what to put in. Before type certificates, there was aircraft specifications. Aircraft specs simply said what equipment could be installed, and to what standards they have to comply to for substitutions. We still have a decently liberal maintenance system, but we have to go through the STC process now. No such thing exists with LSA. The FAA doesn't want the liability (there's always a congressman ready to jump on whatever the big political issue is for brownie points, and aviation is a big one), and I doubt that getting a waiver for a safety directive would be easy at all. That's one big thing I do not like about LSA: the manufacturer is basically THE authority. For the same reason I don't think proceeds for speeding tickets should go to the police department, I don't think the authority that would issue safety requirements should be the same entity that profits from it. Conflict of interest. Flight Design is generally pretty good about things in my experience though. Yeah, if you want an alteration, it's going to cost you; but so will a Designated Engineering Representative or the A&P to write up the data.

[Doug Hereford]

Jim Meade,

I accept your request to provide actual evidence to support arbitrary hose changes. The following is a list of hose failures as a result of age that I am aware of.........................

 

 

 

My list of reasons to support hose changes based on legal requirements and good inspection techniques are noted in my numerous previous replys.

 

 

Doug Hereford

[Anticept]

Does Flight Design or Rotax make money on maintenance or safety directives?

 

Rotax has mandated a change in the voltage regulator placed on planes built after about 2010.  Guess who is paying for the new voltage regulator and the labor to place it on the aircraft?  Rotax...

 

Buying an older and out of warranty aircraft comes with it's own set of expense and risk. 

 

Rotax is one of the better companies. I don't mind manufacturers issuing service bulletins regarding recommended changes. What I don't want is for them to be able to issue enforceable requirements without some sort of oversight or way to void it. There needs to be reasonable burden of proof on both parties to either issue a safety directive, or for me to try to have one exempted.

 

The fuel float issue for example: if that became a safety directive, I would be upset. Rotax does pay for performing the float check, so I'm not too bothered by it. But, they don't always do this for SBs that they issue. Honestly though, their carbs are not the only ones that had these issues; for a long time regular aircraft had the problem too. If the floats sank, the plane pisses fuel everywhere as it sits. I don't know if there's ever been a plane that went down due to a sunken float though that didn't have problems on the ground. These things don't sink in half an hour.

[Anticept]

Jim Meade,

I accept your request to provide actual evidence to support arbitrary hose changes. The following is a list of hose failures as a result of age that I am aware of.........................

 

 

 

My list of reasons to support hose changes based on legal requirements and good inspection techniques are noted in my numerous previous replys.

 

 

Doug Hereford

 

Not rotax, but AD 95-26-13 is worth a read: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/AOCADSearch/26E143C003D4FE0D862569AC005E3501?OpenDocument

 

I pulled out a couple snippets:

 

"SUMMARY: This amendment supersedes Airworthiness Directive (AD) 76-25-06, which currently requires replacing oil cooler hoses on The New Piper Aircraft, Inc. (Piper) Model PA28-140 airplanes, and inspecting for a minimum clearance between the oil cooler hose assemblies and the front exhaust stacks and adjusting if proper clearance is not obtained. This action maintains the clearance inspection and oil cooler hose replacements, requires this inspection and these replacements to be repetitive, and extends the applicability to include PA32 series and other PA28 series airplanes. It also provides the option of installing approved TSO-C53a, Type D oil cooler hose assemblies as terminating action for the repetitive inspection requirement (Anticept's note: it still requires replacement at 1000 hours or 8 years, whichever is first). Numerous incidents/accidents caused by oil cooler hose rupture or failure on the affected airplanes prompted this action. The actions specified by this AD are intended to prevent these oil cooler hoses from failing or rupturing, which could result in engine stoppage and subsequent loss of control of the airplane."

 

"One commenter feels that the FAA is inferring that Piper airplane operators are less competent than other operators by only writing the AD against certain Piper PA28 and PA32 series airplanes. The commenter states that every reciprocating engine-powered aircraft has oil lines and hoses and that the AD should be written against all such aircraft. The FAA does not concur. As stated in the NPRM, "other airplane models have shown a history of oil cooler hose problems; however, most of these have been attributed to leaking oil cooler hoses instead of ruptured hoses or broken hoses as are detailed in the incident/accident reports of the affected PA28 and PA32 series airplanes. The close proximity of the oil cooler hose assemblies to the exhaust stacks in some of the affected airplanes contributes to the hazardous nature of these oil cooler hose failures." The AD is unchanged as a result of this comment."

 

 

 

I'm just bringing this up to point out that there are incidences in other aircraft models pertaining to hose age and proximity to the exhaust system with sudden failures. I do believe that Rotax is being super cautious, but it's interesting to see how other aircraft are affected by aging hoses. Additionally, I think there's an AD to replace all hoses every 7 years for a model of aircraft, and I can't remember which one. Maybe it was piper Comanches.

[Doug G.]

"MFG's found that starting at 4 years of age hose incidents climbed dramatically and every year after that it continued to climb with a rapid rate. These numbers and test is public knowledge on their websites."

Can you give a URL for this please, Roger?

[Doug Hereford]

Anticept,

Some of what you are saying is echoed the the rules regarding the Safety Directive system. Safety Directives must be issued to correct "safety of flight" issues that exist (FAR 21.190 ©(5). That keeps manufacturers from using this system for other purposes, ie profit. FAR 91.327 ((4) gives the operator protection from inappropriate use of the Safety Directive system by the manufacturer as well by confirming that Safety Directives must correct an unsafe condition while maintaining conformance to the applicable consensus standard. It also gives the operator an option with regard to how the unsafe condition is ultimately corrected.

 

For the record, I don't personally think that arbitrary 5 yr. hose changes should be mandated in a Safety Directive. I have only mentioned that possibility in the past to illustrate the proper procedure for correcting unsafe conditions in the SLSA world. Proponents of the 5 yr. hose change typically use abstract examples of safety to support their claims, and are very willing to publicly cast all non-proponents as wreckless cowboys who have no business in the sky.

 

Doug Hereford

[Anticept]

Anticept,

Some of what you are saying is echoed the the rules regarding the Safety Directive system. Safety Directives must be issued to correct "safety of flight" issues that exist (FAR 21.190 ©(5). That keeps manufacturers from using this system for other purposes, ie profit. FAR 91.327 ( (4) gives the operator protection from inappropriate use of the Safety Directive system by the manufacturer as well by confirming that Safety Directives must correct an unsafe condition while maintaining conformance to the applicable consensus standard. It also gives the operator an option with regard to how the unsafe condition is ultimately corrected.

 

For the record, I don't personally think that arbitrary 5 yr. hose changes should be mandated in a Safety Directive. I have only mentioned that possibility in the past to illustrate the proper procedure for correcting unsafe conditions in the SLSA world. Proponents of the 5 yr. hose change typically use abstract examples of safety to support their claims, and are very willing to publicly cast all non-proponents as wreckless cowboys who have no business in the sky.

 

Doug Hereford

 

Hi Doug!

 

I am aware of those regulations, but I still am very suspicious of such systems. We could write letters on a page all day, what matters is the enforcement . Still, right now it seems to work, so I am not overly concerned, but I still retain vigilance.

[Tom Baker]

Not rotax, but AD 95-26-13 is worth a read: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/AOCADSearch/26E143C003D4FE0D862569AC005E3501?OpenDocument

 

I pulled out a couple snippets:

 

"SUMMARY: This amendment supersedes Airworthiness Directive (AD) 76-25-06, which currently requires replacing oil cooler hoses on The New Piper Aircraft, Inc. (Piper) Model PA28-140 airplanes, and inspecting for a minimum clearance between the oil cooler hose assemblies and the front exhaust stacks and adjusting if proper clearance is not obtained. This action maintains the clearance inspection and oil cooler hose replacements, requires this inspection and these replacements to be repetitive, and extends the applicability to include PA32 series and other PA28 series airplanes. It also provides the option of installing approved TSO-C53a, Type D oil cooler hose assemblies as terminating action for the repetitive inspection requirement (Anticept's note: it still requires replacement at 1000 hours or 8 years, whichever is first). Numerous incidents/accidents caused by oil cooler hose rupture or failure on the affected airplanes prompted this action. The actions specified by this AD are intended to prevent these oil cooler hoses from failing or rupturing, which could result in engine stoppage and subsequent loss of control of the airplane."[/size]

 

"[/size]One commenter feels that the FAA is inferring that Piper airplane operators are less competent than other operators by only writing the AD against certain Piper PA28 and PA32 series airplanes. The commenter states that every reciprocating engine-powered aircraft has oil lines and hoses and that the AD should be written against all such aircraft. The FAA does not concur. As stated in the NPRM, "other airplane models have shown a history of oil cooler hose problems; however, most of these have been attributed to leaking oil cooler hoses instead of ruptured hoses or broken hoses as are detailed in the incident/accident reports of the affected PA28 and PA32 series airplanes. The close proximity of the oil cooler hose assemblies to the exhaust stacks in some of the affected airplanes contributes to the hazardous nature of these oil cooler hose failures." The AD is unchanged as a result of this comment."[/size]

 

 

 

I'm just bringing this up to point out that there are incidences in other aircraft models pertaining to hose age and proximity to the exhaust system with sudden failures. I do believe that Rotax is being super cautious, but it's interesting to see how other aircraft are affected by aging hoses. Additionally, I think there's an AD to replace all hoses every 7 years for a model of aircraft, and I can't remember which one. Maybe it was piper Comanches.

This is a good example of why replacing all hoses at 5 years is an arbitrary number. I have been maintaining Piper aircraft since before this AD 95-26-13 came out. This is another case of the FAA issuing a AD because mechanics were not doing their jobs, and not because the hoses were unsafe. Piper recommends all hoses be changed every 8 years or 1000 hours. The AD only covers oil cooler hoses, while all the other hoses in the engine compartment are made from the same material. The Piper aircraft that had problems that prompted this AD were the ones with front mounted oil coolers. When you have a front mounted oil cooler the lines run very close to the exhaust system. This increased heat causes the hoses to deteriorate quicker than other hoses. This is the same for our Rotax powered aircraft. Some of the hoses are exposed to greater environmental factors than others. The 5 year number is intended to cover the hoses operating in the harshest of conditions, because they need replaced. Other hoses likely do not need replaced because of their location and environment.

 

BTW there is a FAA approved AMOC for the Piper oil cooler hoses that allows for inspection on condition for oil cooler hoses going to rear mounted oil coolers, because of their location away from the exhaust.

[Roger Lee]

We all fall on some side of a fence for this issue. No matter where the line gets drawn or who draws is it will always be controversial depending on what side of the fence you are on. There will never ever be an agreement. it will always be too long or too short a time for someone.

 

Bottom line is someone had to draw a line in the sand and I'm sure it was on the side of caution. 

[Tom Baker]

We all fall on some side of a fence for this issue. No matter where the line gets drawn or who draws is it will always be controversial depending on what side of the fence you are on. There will never ever be an agreement. it will always be too long or too short a time for someone.

 

Bottom line is someone had to draw a line in the sand and I'm sure it was on the side of caution.

Roger, what 5 year date do you use to determine when it is time for hose replacement?

[Doug Hereford]

Tom Baker,

I have had the same observations with regard to the Piper AD. Unsafe conditions were definitely brought on by non-adherence to accepted routing, securing and inspection practices, and not as a result of hose age.

Anticept may want to amend part of his NOTE that is imbedded in the body of his post above.

I have seen similar hose change recommendations from almost all GA manufacturers.

 

As far as rubber age vs deterioration, someone mentioned Gates. My 2002 Silverado has gates hoses. All original, 289,000 miles. I keep it

going by keeping the hood down.

 

Doug Hereford

[Roger Lee]

Hi Tom,

 

Not 100% sure I understand the question, but if I do then I just use the date the plane was put into service. I would think most of ours had hose on about 1-4 months before we got them as an average.  I guess you would need to always look at the logbook to make a solid determination. There can be extenuating circumstances like an experimental aircraft with an engine that just sat 1-2 years before use. Ozone  and chemical vapors kill hoses too.

 

"As far as rubber age vs deterioration, someone mentioned Gates. My 2002 Silverado has gates hoses. All original, 289,000 miles. I keep it

going by keeping the hood down.

Doug Hereford'

 

 

I have certainly seen hoses on planes that are 10+ years old, but like anything else it may last and you may be the lucky one it doesn't.

That's the whole problem, nobody ever knows.

 

​Some people like gambling more than others.

 

 

Hoses are like this:

 

Diving under water with assistance of some sort has been around since the 1300's. As it progressed closer to what we know of today as SCUBA  or Surface supplied air around  1939-1942 and they needed some sort of diving decompression tables. In 1956 the US Navy introduced those tables. Depending on what side of the fence you fell on back then you abided by them or didn't. The recreational diver had to use these tables. Problem was the tables had a 20% incident rate in them that the military thought was acceptable. Later in the late 1970's or early 1980's the dive industry said a 20% incident rate wasn't acceptable and revised the tables for the civilians and made the tables more conservative. Depending on what side of the fence you fell on you either used the new tables or the old. For the last 30 years the new tables have been taught. Now can you push the envelope and use the old tables and get away with it, Absolutely, but main stream decided to fall on the side of caution.

 

Here we are with hoses. are you old school Navy with a 20% incident rate  or new school conservative?

How many people have had broken hose less than 5 years and more than 5 years and had to land off field, seize an engine or got hurt or killed. Do you want the odds more in your favor or push the envelope?

 

What side of the fence?

 

Everyone gets to make their own choice. Just make sure you don't make the wrong choice for your passenger.

I have no issues with risking my own life, but smart enough to put the odds in my favor. I will not ever again risk another person's and since I carry passengers that means not risking mine or theirs on one of my flights or any other of my off kilter adventures.

 

You might own 5 aircraft and never ever change a hose and get away with it. How many have not been that lucky? 

[Roger Lee]

Probably better to put this to rest. There isn't anything new we can offer to make things different. We all will take away from the post what we want and will do what we want. Beating each other up isn't in our best interest. 

[Tom Baker]

Roger, when I ask about date I was referring to the date of manufacture of the hose, compared to the aircraft, compared to when it is put in service. Do you check the date of manufacture for the hoses you are installing?

[Roger Lee]

Hi Tom,

 

No I don't. I figure and possibly naively that it should be within a few months. I would think aircraft like the CT's hose is within 6 months old. Just a guess though.

I look at every engine MFG date and go from there. Engine MFG date on some can be quite different than some aircraft service dates.

 

 

p.s.

I usually don't worry about hose being an extra few months old. 6 years wouldn't bother me, but I tend to follow the rules and then not having to justify my actions legally if the issue came up. Courts, the FAA, insurance companies and owners don't tend to hold you in bad standing nor do you have to try and prove the rest of the world wrong when you follow the rules. I spent too much time in court over my 30 years in public safety and watching lawyers burn people to the ground for failing in following rules.

[Anticept]

Cure dates are printed on hoses, and manufacturers of said hoses recommend replacement based on the printed date. I've heard a bunch of numbers thrown around regarding cure times on hoses too.

[Tom Baker]

Hi Tom,

 

No I don't. I figure and possibly naively that it should be within a few months. I would think aircraft like the CT's hose is within 6 months old. Just a guess though.

I look at every engine MFG date and go from there. Engine MFG date on some can be quite different than some aircraft service dates.

 

 

p.s.

I usually don't worry about hose being an extra few months old. 6 years wouldn't bother me, but I tend to follow the rules and then not having to justify my actions legally if the issue came up. Courts, the FAA, insurance companies and owners don't tend to hold you in bad standing nor do you have to try and prove the rest of the world wrong when you follow the rules. I spent too much time in court over my 30 years in public safety and watching lawyers burn people to the ground for failing in following rules.

On everything, or just when it suits you?