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More things done wrong

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Here are a few more "Doing it wrong" photos.

 

The wrong type of clamp on a firesleeve. Use the proper clamp (i.e.a Band-It clamp) and not worm drive hose clamps. There are a few others, but this is the most common. Band clamps in general are okay.

 

Here is a biggy. The wrong clamps on the fuel line inside the instrument panel. The leak was so bad that the fuel all drained out over a period of a month or two. 20 gals. gone. The leak was so bad you could see it leaking. What was the mechanic thinking.

 

Screw clamps on the fuel line at the fuel pump are illegal. It will take the same amount of time and effort to use the right clamp. Watch your mechanics and don't let them do this.

 

The fuel pressure remote mount was so short it was wire tied on and not mounted as prescribed by FD.

 

We trust our mechanics to know and do the right thing, but as you can see that isn't always the case. It is your responsibility to make sure they do the right thing and maybe even inspect their work. Don't pay someone to do it wrong and then have to pay twice for the same job to do it right.

 

It is very easy to do the right thing.

 

JUST PUT IT BACK LIKE YOU FOUND IT AND YOU CAN'T GO WRONG. DON'T TAKE LIBERTIES WITH AN SLSA..THE OWNER BECOMES JUST A LIABLE TO THE FAA OR THE INSURANCE COMPANY AS THE MECHANIC.

Wrong type firesleeve clamp.pdf

Unfinished Exposed sharp band clamp end.pdf

Wrong clamp and leak in instrument panel.pdf

Wrong clamps on fuel pump lines.pdf

Wrong firesleeve clamp.pdf

Wrong fuel line clamp with a bad leak.pdf

Illegal fuel pressure remote mount.pdf

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Somebody has to ask the dumb questions. I understand that band it clamps are the specified item for fire sleeves and thus need to be used. but what is there real superiority over a scew clamp,as long as the screw clamp is not tightened to sqush the hose????

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Clamps must withstand temps to the standards below and automotive and plain hardware wormdrive clamps do not. The stainless steel Band-It clamp does. That said there are other band clamps that could be used, but too many people are trying to use the wrong clamps. The Band-It style clamps are supposed to be tamper proof, won't slip or fail. Many people over tighten wormdrive clamps and strip the mechanism. The raised ridge wormdrive is a better clamp than the open notched type wormdrive like you may get in the hardware store. One problem here is for the mechanic. If one mechanic puts the wrong clamp on and then the next mechanic inspects the plane and after that the plane has a fire or failure the last mechanic to inspect the plane is responsible, not the one who did it in the first place. It behooves the last mechanic to make the correction. These are the two items that fire sleeving try to adhere to. That said some SLSA MFG's have done it differently and don't meet the standard. I have seen heat shrink applied over the ends of firesleeve. Worthless and doesn't meet the intent of firesleeve. Band-It clamps for firesleeve are pretty much an industry standard.

 

Firesleeve and our other silicone rubber coated fiberglass (fibreglass) materials withstands 500°F / 260°C continuous exposure; Molten Splash at 2200°F / 1205°C for periods up to 15 minutes and short excursions to 3000°F / 1650°C.

 

hose assemblies should meet the fire resistance requirements of FAA TSO - C53a (fuel and Oil system hose assemblies),

t

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Copied: This is one reason Rotax picked it's 5 year rubber replacement not to mention over 4 million flight hours of experience.

"The service life of a hose assembly depends on the application and the environment in which it is used. Most hose assembly failures result from kinking, chafing, impact, flexing and temperature cycling. They also age and become brittle due to molecular changes with time and reactions with both the internal and external fluids with which they come into contact. One of the catastrophic modes of failure is when the hose comes out of its end fittings. This is primarily because of the permanent set that the hose material undergoes which reduces the retention forces on the end fittings and is the underlying reason for specifying a calendar time life for the hoses. Federal Aviation Administration (FAA) AC No.20-7N, General Aviation Inspection Aids Summary, recommends, “all flexible flammable fluid carrying hoses in the engine compartment be replaced at engine overhaul or every five years which ever occurs first”. Even when a calendar time life is specified for the hoses, it is necessary to have regular inspections for damage due to external forces to ensure continued airworthiness. Specification of a service life for hoses is not a substitute for regular inspection and maintenance of hoses."

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The firesleeve ends should all be protected by either a liquid End Dip or a fire rated end wrap tape. The End Dip is sold in a quart can and is about $185. You should dip it down in about 1"-1.5" and let it sit out and dry. The end wrap tape can go on immediately.

 

The end wrap tape is an excellent alternative to using end dip and especially nothing at all and it isn't that expensive. It comes in a 36' roll and either 1" or 1.5" wide.

Firesleeve with Clamp and End Wrap Tape 173x.jpg

Firesleeve with Clamp 173x.jpg

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Copied: This is one reason Rotax picked it's 5 year rubber replacement not to mention over 4 million flight hours of experience.

"The service life of a hose assembly depends on the application and the environment in which it is used. Most hose assembly failures result from kinking, chafing, impact, flexing and temperature cycling. They also age and become brittle due to molecular changes with time and reactions with both the internal and external fluids with which they come into contact. One of the catastrophic modes of failure is when the hose comes out of its end fittings. This is primarily because of the permanent set that the hose material undergoes which reduces the retention forces on the end fittings and is the underlying reason for specifying a calendar time life for the hoses. Federal Aviation Administration (FAA) AC No.20-7N, General Aviation Inspection Aids Summary, recommends, “all flexible flammable fluid carrying hoses in the engine compartment be replaced at engine overhaul or every five years which ever occurs first”. Even when a calendar time life is specified for the hoses, it is necessary to have regular inspections for damage due to external forces to ensure continued airworthiness. Specification of a service life for hoses is not a substitute for regular inspection and maintenance of hoses."

 

Roger,

 

 

Can you give me the citation for this verbiage above? The only place I could find it on a rather cursory search was in CASA (Australian) regulations. That regulation cites FAA AC 20-7N but a search of the FAA site does not list it as either a current or cancelled AC.

 

I do agree with the last sentence, and want to learn better how to do a good job of such inspections and maintenance.

 

FAA TSO - C53a, February 1, 1961, is a good two page document which is not very specific. What is the requirement that it be applied to SLSA? If it is not mandated, then various manufacturers could legally apply various techniques to their fabrication and be in compliance with AMTA. If that is the case, then one could argue that they are not following best practices, but it would seem to me that mechanics would have to advise the owner that the situation was legal but then tell them why the mechanic felt it was unsatisfactory and how to remedy it. Then, it's the owners responsibility to make a decision.

 

The question arises as to what happens if the manufacturer and/or mechanic find some practice mandatory but the FAA says it is not requried and the owner does not want to correct it the way the manufacturer or mechanic prefer. We see this a lot in General Aviation where mechanics try to persuade owners to do something that is not strictly required. The main example that comes to mind is the Cirrus practice of SBs. Cirrus says they are mandatory and the FAA says they are not. Cirrus tries to pressure the owner by claiming they will not warranty the airplane if the procedure is not done. The mechanic says he will not sign off the aircraft unless the procedure is done because of liability. The owner has the law on his side but feels considerable pressure to give in to the manufacturer and mechanic, especially if the owner is not technically savvy or forceful. This is the reason that the certificated GA community has people like Mike Busch who make a living by calling up mechanics on behalf of owners and proving to the mechanic what the FAA requires and what it doesn't require.

 

One avenue for the SLSA owner is to recertify their plane as ELSA. It seems to avoid considerable potential for conflict.

 

What we seem to see is that some AMTA procedures are not consistent with FAA Part 43 and a few traditional mechanics try to force SLSA into Part 43. We see some manufacturers wanting to insist on things the FAA says are not required, such as Rotax engine courses. The owner gets confused by the apparent conflicts and doesn't know whom to believe.

 

Well, hopefully public forums like this one will hash these questions out and resolve them to everyone's satisfaction and to the benefit of the LSA community. I do know that in my own case, I'm more and more appreciative of solid references to regulations.

 

 

 

 

 

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  • Federal Aviation Administration (FAA), Technical Standards Order (TSO) TSO C42 Propeller Feathering Hose Assemblies.
  • FAA TSO-C75 Hydraulic Hose Assemblies
  • FAA TSO-C53a, Fuel and Engine Oil System Hose Assemblies.
  • FAA TSO -C140, Fuel, Engine Oil and Hydraulic Fluid Hose Assemblies.
  • FAA Advisory Circular (AC) 43.13-1B CHG 1. Acceptable Methods, Techniques and Practices – Aircraft Inspection and Repair.
  • FAA AC 20-7N General Aviation Inspection Aids Summary.
  • SAE Aerospace Recommended Practice (ARP) ARP 1658 REV B, Hose Assemblies, Installed, Visual Inspection Guide.
  • SAE AIR 1569 REV A, Handling and Installation Practice for Aerospace Hose Assemblies.
  • United Kingdom (UK) Civil Aviation Authority (CAA) Leaflet 5-5 “Civil Aircraft Airworthiness Information and Procedures, Hoses and Hose Assemblies”.
  • Aeroquip Bulletin AA91 “7 Quick Ways to spot hose line problems before they cause trouble” 1998

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And these apply to AMTA airplanes?

 

I'll check them out for condition inspection guidelines. That will be helpful. The two above that I've read are not specific and not of much direct help. But, I'll look at the others. Thanks for the list. I'm learning.

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I couldn't find a reference to AC 20-7N either but it appears that Rotax is not the only one that recommends changing the hoses every five years. Lycoming does as well. I found an NTSB report of a fatal 172M crash where the cause of engine failure was a hose that hadn't been replaced either during overhauls or every 5 years as stated in Section 3 of Lycoming's maintenance manual. From the NTSB:

A contributing factor in the accident was the failure of company maintenance personnel to replace the flexible oil cooler hoses during engine installation following overhaul, as recommended by the engine manufacturer.

Search the NTSB site for N9336H which references the manual.

Kind of wonder who the family of the dead CFI sued for negligence. :(

 

I guess we can argue whether one should follow a recommendation but I tend to think the manufacturer knows more about their product than me. :)

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  • Federal Aviation Administration (FAA), Technical Standards Order (TSO) TSO C42 Propeller Feathering Hose Assemblies.
  • FAA TSO-C75 Hydraulic Hose Assemblies
  • FAA TSO-C53a, Fuel and Engine Oil System Hose Assemblies.
  • FAA TSO -C140, Fuel, Engine Oil and Hydraulic Fluid Hose Assemblies.
  • FAA Advisory Circular (AC) 43.13-1B CHG 1. Acceptable Methods, Techniques and Practices – Aircraft Inspection and Repair.
  • FAA AC 20-7N General Aviation Inspection Aids Summary.
  • SAE Aerospace Recommended Practice (ARP) ARP 1658 REV B, Hose Assemblies, Installed, Visual Inspection Guide.
  • SAE AIR 1569 REV A, Handling and Installation Practice for Aerospace Hose Assemblies.
  • United Kingdom (UK) Civil Aviation Authority (CAA) Leaflet 5-5 “Civil Aircraft Airworthiness Information and Procedures, Hoses and Hose Assemblies”.
  • Aeroquip Bulletin AA91 “7 Quick Ways to spot hose line problems before they cause trouble” 1998

TSO C42 does not exist. It is cited in a CASA document but is not on the FAA TSO list.

 

TSO C75 9/4/63 (a) Applicability. Mini-mum performance standards are hereby established for hy-draulic hose assemblies which are to be used on U.S. civil transport category aircraft. This TSO doesn't apply to SLSA, it seems to me.

 

 

TSO C53a - 2/1/63 FUEL AND ENGINE OIL SYSTEM HOSE ASSEMBLIES. It says for Type C hose that sleeves or covers may be used and if they are, "Sleeves or covers shall be secured to the hose assembly so that fire-resistant properties will be maintained." I don't know if it applies ot SLSA or not.

 

FAA AC 43-13-1B This is current document and, talking about hydraulic hoses, says, "Sleeve or pro-tective covers shall be secured to the hose as-sembly so that fire-resistant properties will be maintained." I'd like to see some more detail about what that entails. It also says, "This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions. " So, whatever the manufacturer says has precedence.

 

FAA AC 20-7N General Aviation Inspection Aids Summary. Not found in current list of FAA ACs

 

SAE Aerospace Recommended Practice (ARP) ARP 1658 REV B, Hose Assemblies, Installed, Visual Inspection Guide. 1997/08/01. Commercial document costs $66. I don't have any information that it is required, but without seeing I can't say whether it's a useful document or not for inspection. The short description makes it sounds like it would be.

 

SAE AIR 1569 REV A, Handling and Installation Practice for Aerospace Hose Assemblies. Not found, except as a reference in another document - see below.

 

  • United Kingdom (UK) Civil Aviation Authority (CAA) Leaflet 5-5 “Civil Aircraft Airworthiness Information and Procedures, Hoses and Hose Assemblies”.
  • Aeroquip Bulletin AA91 “7 Quick Ways to spot hose line problems before they cause trouble” 1998

I kind of skipped over the latter two as being obviously foreign and not likely an issue with Flight Design.

 

Well, Roger did me a favor by putting up this list. It did me a lot of good to do the research on this list. First, I found out that it can be challenging to find all the documents, even when one has looked for similar ones before. It makes one appreciate the mechanic who does a diligent job of research. He earns his money. Secondly, it reminded me that a basic premise in determining if a document if required is to read the applicability statements. Sometimes we skip over that when we head right for a section of interest, but of course we all should review the purpose and applicability paragraphs once in a while. Some of these don't apply to SLSA from what I can gather. Thirdly, a list like this helped me keep in mind the difference between what is required and what is useful and even beneficial to know. Some of the knowledge was general, some more specific, but it didn't hurt me any to review what was said even when I didn't have to follow it.

 

Roger's list also challenged me to do a little more research, since the list is identical in every respect to the Bibliography of the Civil Aviation Safety Authority (CASA) of the Australian government document AWB 02-6 Issue 1, 22 July 2003 Flexible Hose Assemblies - Maintenance Practices. Given that it's nine years old, cites obsolete documents, has no authority over our U.S. practices, it's still a useful point of departure for studying this topic. Here is the URL. It's a decent, short discussion of hose inspections.

 

http://www.casa.gov.au/scripts/nc.dll?WCMS:STANDARD:1001:pc=PC_90645

 

I guess my next task, in between fixing my glider, working on a tractor, getting my planter ready and doing a little flying, will be to do some more research into how to perform a condition inspection on hoses. Roger's list at least gave me a start.

 

 

 

 

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Jim, whether we like it or not those of us with SLSA aircraft have to follow the manufactures maintenace and inspection procedures because it is required by regulation. Look at 91.327 b 1

(1) The aircraft is maintained by a certificated repairman with a light-sport aircraft maintenance rating, an appropriately rated mechanic, or an appropriately rated repair station in accordance with the applicable provisions of part 43 of this chapter and maintenance and inspection procedures developed by the aircraft manufacturer or a person acceptable to the FAA;

Unless you can find some one the FAA says can tell you otherwise I think the hoses have to be changed.

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Tom,

 

I appreciate your point. Thanks for reminding me of 91.327.

 

Although I am not a fan of time based maintenance, feeling condition based is better, I am not contesting the apparent present need to change SLSA Rotax engine hoses at 5 years.

 

My continuing interest is in learning as much as I can about how to do a condition inspection on hoses, and on what regulations govern how hoses are maintained. I'll keep plugging away at that.

 

 

 

 

 

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Tom,

 

I appreciate your point. Thanks for reminding me of 91.327.

 

Although I am not a fan of time based maintenance, feeling condition based is better, I am not contesting the apparent present need to change SLSA Rotax engine hoses at 5 years.

 

My continuing interest is in learning as much as I can about how to do a condition inspection on hoses, and on what regulations govern how hoses are maintained. I'll keep plugging away at that.

 

Jim, for an SLSA 91.327 governs how the hoses are to be maintained by requiring that you follow manufactures procedures. To do a really good inspection I think you need to remove the hose and fire sleeve. When you go to this much trouble you might as well go ahead and replace the hose. Manufactures of GA airplanes make suggestions about when to replace hoses. This replacement has to be done on part 135 airplanes, but not on part 91 airplanes. When to many people ignore what the manufacture says and there are accidents then you wind up with an AD on hoses like Piper and Cessna have. I sure someone inspected those hoses and thought they were OK before the accidents that prompted the AD's.

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Tom,

 

I have a hunch you mean an inspection at the 5 year mark, because I don't think we are expected to remove hoses during an annual. There have been quite a few discussions about hoses and the 5 year replacement time. Some of the hoses seem bad enough that they were probably not good well before 5 years. So, how do we tell? Pinch? Look? Squeeze? Etc. But, probably not remove unless we have some indication that causes us concern. This is the part of the hose condition inspection that I'm trying to get smarter about.

 

Your observation that if one removes the hose one might as well replace it has a lot of merit. Some owners are not going to be happy replacing a hose just because it came off when it looks in hind sight to be OK.

 

As you intimate, we're going to get owners who want to defer unnecessary maintenance. Some will want to defer all maintenance they can get away wtih.

 

If the day comes when the 5 year hose replacement is not mandated, it is likely that mechanics will feel the need to know how to judge hose condition because some owners won't agree with what they will call a prophylactic replacement. How, then, does a mechanic justify his desire to replace the hoses?

 

Well, I'm getting a little off topic, but I appreciate your reply and I'll continue to try to learn more about how to judge hose conditions.

 

 

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Jim, the hoses do get inspected on condition up to the 5 years. The inspection is for obvious defects by checking flexibility of the hose, discoloration, and wetness of the fire sleeve. Because ultimately these inspections don't give the total picture of the hoses health the requirement for replacement is there. I'm sure the hoses could be tested in some way to verify their condition, but this would require removal and bench testing, and the way our hoses are attached it often damages the hose during removal. Tom

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The firesleeve ends should all be protected by either a liquid End Dip or a fire rated end wrap tape. The End Dip is sold in a quart can and is about $185. You should dip it down in about 1"-1.5" and let it sit out and dry. The end wrap tape can go on immediately.

 

The end wrap tape is an excellent alternative to using end dip and especially nothing at all and it isn't that expensive. It comes in a 36' roll and either 1" or 1.5" wide.

 

As an alternative to end dip, the use of high temp RTV on the ends is legal. However this is very sloppy looking and appears to have been done by the local daycare on finger painting day. :D

 

I use the RTV method, but I go one step further and put about 3 inches of heat shrink on the ends after the RTV is applied. It just looks professional and conceals any uglyness.

post-390-0-24638900-1331639182_thumb.jpg

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The problem with the heat shrink is you can't inspect the clamps and check for leaky fittings. You can put a screwdriver on some of the hoses that have screw clamps to check them for loosening or hose shrinkage. I find the screw clamps loose all the time for a while, especially when new or right after a hose change and things settle. If RTV silicone is smeared all over under it it will compound the problem. You can't see if someone put the wrong clamps on. You have basically hidden an inspection point and if sealed up with RTV then it can be leaking under the RTV back into the hose and you would never know. .

For the owners edification, you can't use heat shrink to seal the ends of the fire sleeve.

They have to have an approved band clamp and the ends have to be sealed from fluid absorption. The approved industry standard is to either use "End Dip", fire rated self vulcanizing tape or red high temp silicone thinned thinned with toluene to seal the fire sleeve ends. I don't like to high temp silicone way just because it can be messy, sticks to everything and makes servicing and inspecting the clamps a PITA. Heat shrink doesn't have the same 2000 degree fire rating as the fire sleeve. Hec you can shrink it with only 250F and hold a match under it and watch it burn away. Matter of fact regular electrical heat shrink is gone in seconds in a fire and fluids can stick wick up under either end during normal use. It isn't an approved ASTM standard or approved by Flight Design. I just re-did a plane out of Florida with no clamps or garden variety wormdrive clamps on the fire sleeve and fuel lines. The wrong clamps were used in the instrument panel on the metal sweep tube. The leak was so bad he drained 20+ gals through the panel. Smearing red high temp silicone all over the fire sleeve ends, clamps and fittings to fully encase it and no clamp is not correct either. You can't service the fitting and clamp without trying to cut and remove all that crap to even check it to make sure it's snug or not leaking under the silicone back into the hose. Between this aircraft and another one a mechanic took liberties with from California they were expensive annuals and fixes.

 

Like I told the owners, you paid someone to actually do it wrong and now you have to pay twice for the same job and because it takes so much time to correct it. They pay for the same job twice and it gets expensive. The best way for an owner that is not sure how it should be, tell the mechanic to put it back the way he found it. Then you know it is okay with the aircraft MFG. FD spent good money and time to get our planes correct under the standards, why let a mechanic change that. Bottom line, the owner is responsible if something happens. If a fire or an issue ensued because of this and the insurance company thinks this either caused the problem or lead to more damage they aren't going to pay because someone altered the factory approved method and didn't follow the industry standard or the factory maint. manual. Then I would think the owner is coming after the mechanic.

It is so easy to use the proper clamps or approved method why use the wrong one, it doesn't save any time and usually cost the same.

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Roger, I like the approved red heat tape that you showed finishing off a fire sleeve in an earlier post in this thread. Where does one purchase this (I know it's not at ACE!). Aircraft spruce or one of the suppliers? Also, do you have a few photos you might post which show the correct clamps in the different applications? Thanks.

 

 

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Hi Dick,

That's what I like a man of action.wink.gif

The correct clamps and tools are in this same thread under things done right. The tape could be used for other protection services.

 

 

http://www.americanfiresleeve.com/high-temperature-heat-flame-fire-pyro-resistant-protection-silicone-rubber-self-fusing-end-wrap-tape-aa59163-mil-i-46852.html

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The problem with the heat shrink is you can't inspect the clamps and check for leaky fittings. You can put a screwdriver on some of the hoses that have screw clamps to check them for loosening or hose shrinkage. I find the screw clamps loose all the time for a while, especially when new or right after a hose change and things settle. If RTV silicone is smeared all over under it it will compound the problem. You can't see if someone put the wrong clamps on. You have basically hidden an inspection point and if sealed up with RTV then it can be leaking under the RTV back into the hose and you would never know. .

For the owners edification, you can't use heat shrink to seal the ends of the fire sleeve.

They have to have an approved band clamp and the ends have to be sealed from fluid absorption. The approved industry standard is to either use "End Dip", fire rated self vulcanizing tape or red high temp silicone thinned thinned with toluene to seal the fire sleeve ends. I don't like to high temp silicone way just because it can be messy, stcicks to everything and makes servicing and inspecting the clamps a PITA. Heat shrink doesn't have the same 2000 degree fire rating as the fire sleeve. Hec you can shrink it with only 250F and hold a match under it and watch it burn away. Matter of fact regular electrical heat shrink is gone in seconds in a fire and fluids can stick wick up under either end during normal use. It isn't an approved ASTM standard or approved by Flight Design. I just re-did a plane out of Florida with no clamps or garden variety wormdrive clamps on the fire sleeve and fuel lines. The wrong clamps were used in the instrument panel on the metal sweep tube. The leak was so bad he drained 20+ gals through the panel. Smearing red high temp silicone all over the fire sleeve ends, clamps and fittings to fully encase it and no clamp is not correct either. You can't service the fitting and clamp without trying to cut and remove all that crap to even check it to make sure it's snug or not leaking under the silicone back into the hose. Between this aircraft and another one a mechanic took liberties with from California they were expensive annuals and fixes.

 

Like I told the owners, you paid someone to actually do it wrong and now you have to pay twice for the same job and because it takes so much time to correct it. They pay for the same job twice and it gets expensive. The best way for an owner that is not sure how it should be, tell the mechanic to put it back the way he found it. Then you know it is okay with the aircraft MFG. FD spent good money and time to get our planes correct under the standards, why let a mechanic change that. Bottom line, the owner is responsible if something happens. If a fire or an issue ensued because of this and the insurance company thinks this either caused the problem or lead to more damage they aren't going to pay because someone altered the factory approved method and didn't follow the industry standard or the factory maint. manual. Then I would think the owner is coming after the mechanic.

It is so easy to use the proper clamps or approved method why use the wrong one, it doesn't save any time and usually cost the same.

 

 

I wrap the ends with heat shrink for cosmetic purposes only, AFTER I smear RTV on the ends as I said earlier. The way I do it looks exactly like your pic with the fire sleeve tape. No difference for inspecting the clamps. They both cover up the clamps!!!

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The picture I copied had it covered. I never cover them. I just removed a handful of worm-drive clamps on this CT and some were covered with RTV and it was not only hard to see what they were, but a pain to try and get all the RTV off the hose and clamps to replace them.

If the plane I just did an annual had the heat shrink along with the wrong clamps I would have had to cut it all off just to inspect the rest of the clamps because some were the wrong ones.

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