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airworthiness, dimmers, and other stuff
From: 8300.10 chg 17 - The Inspectors Handbook
"(2) Airworthiness: (3) Since “airworthiness” is not defined in the FA Act of 1958, as amended, or in the regulations, a clear understanding of its meaning is essential in conducting a violation investigation. A review of case law relating to airworthiness reveals two conditions that must be met for an aircraft to be considered “airworthy.” These conditions a (a) The aircraft must conform to its type design (certificate). Conformity to type design is considered attained when the required and proper components are installed and they are consistent with the drawings, specifications, and other data that are part of the type certificate. Conformity would include applicable supplemental type certificates and field approved alterations. (b) The aircraft must be in condition for safe operation. This refers to the condition of the aircraft with relation to wear and deterioration. Such conditions could be skin corrosion, window delamination/crazing, fluid leaks, tire wear, etc." part (b) is pretty straight forward although this is the part that open to the most "opinion".....what is ok to one won't be ok to another. Admittedly, most mechanics err on the side of safety here. part (a) states that the aircraft must conform to its type design.....basically, what this means is that the airplane must be in a condition that matches the day it came from the factory -or- be in conformance with applicable STC's or field approvals. The form 337 is the official vehicle that indicates a change from the original type design, that is its purpose. (that’s why its important that the IA doing your annual have all these 337’s available for review). Interpreting further, repairs or alterations that can be construed as minor must be documented in the aircraft records –the catch- here is that these repairs, alterations and the parts associated with them must be shown to be “consistent with the drawings, specifications, and other data that are part of the type certificate”. The big problem here is that most manufacturers will not release the type of information required to make this determination in the field, and even if they did, it would probably require the services of a DER to verify conformity. No mechanics, at least that I’m familiar with are capable of doing an engineering analysis that would satisfy the FAA. So, the next best way to assure conformity is to buy parts from the original manufacturer. They want you to buy parts from them to maintain their products for reasons of liability anyway. Additionally, parts with PMA or TSO approval could (not absolutely would) also be acceptable. Getting back to what got ME involved with this thread from the beginning was a non-standard panel lighting dimmer system. From the definition above it should be very obvious that unless the aircraft is equipped with the system it came from the factory with, it is not considered airworthy unless there is a 337 associated with an STC or field approval for the system installed......because the aircraft no longer conforms to its type design, or quite literally, it doesn’t match the blueprints the manufacturer supplied to the FAA when the aircraft was certificated. This is an issue most owners just don’t understand. I’m not saying that modern PWM dimming systems are bad or good, I’m not saying the original lighting system is bad or good, and I’m not saying that the approval/certification system is fair and just.....I’m just saying that is the way it is. And as an A&P/IA/chief inspector dats wot I godda do! Another issue that I will mention (but I WILL NOT discuss) is the issue of parts for this dimmer system. The regs would imply that the $20 2N3055 transistor from Piper is a suitable replacement part but the $1.50 2N3055 transistor from Radio Shack is not a suitable part. The implication is that the batch of transistors Piper gets, each and every unit is tested and verified to “some standard” whereas the batch that Radio Shack gets has only one in every 10,000 units tested to “some other standard” thus driving up the price for the part the manufacturer sells. The saving grace here is IF the manufacturer lists the part by its generic number in the parts catalog....then the Radio Shack part would probably be OK. This also touches on the issue of owner manufactured parts. FAR 21.303 gives the owner authority to manufacturer parts, however, what makes this impractical in most cases is AC 20-62 which states: "4. DEFINITIONS. The following definitions apply to this AC: b. Acceptable Parts. The following parts may be found to be acceptable for installation on a type certificated product: (1) Standard parts (such as nuts and bolts) conforming to an established industry or U.S. specification. (2) Parts produced by an owner or operator for maintaining or altering their own product and which are shown to conform with FAA-approved data. (3) Parts for which inspections and tests have been accomplished by appropriately certificated persons authorized to determine conformity to FAA-approved design data." The dreaded words “FAA approved data” appear in (2) and (3).....when an owner supplies a mechanic with a part he has produced, he must also supply the mechanic with data to prove compliance with the necessary specifications. How do you get these specifications and how do you show compliance with them? Remember, the installing mechanic has the responsibility to assure the parts he installs meet certain specs.....FAR 43.13 states: "(b) Each person maintaining or altering, or performing preventive maintenance, shall do that work in such a manner and use materials of such a quality, that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition (with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness)." I might make note here that the above excerpt also puts the burden of acceptable parts on an owner performing preventive maintenance. The primary point is that this is why mechanics with a good working knowledge of the FARs will balk when you bring a part to them of questionable origin for installation onto a type certificated product. This brings to mind something that was discussed at great length in this forum....the infamous Yellow Tag. To clarify that point, this document is nothing more than a log book entry when the log books aren’t available. Yellow is the accepted color, but it can be any color you desire as long as it contains the required information and signatures. It doesn’t even have to be a tag. It can actually be a log book entry, it can be an 8 ½ X 11 sheet of paper, it can even be the back of a McDonalds napkin as long as it contains the required information and signatures and becomes a part of the permanent aircraft records. Yes Mr. Weir, I realize that everyone has an opinion and this is mine, as “smelly” as it may be. I welcome you or your General Counsel buddy to cite specific regulatory references that refute my opinion. I may even learn something new. |
#2
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Sorry, there is a recent FAA decision that replacement of equivalent
parts may be made at the A&P's discretion. An A&P can, in fact, accept a Radio Shack 2N3055 transistor even though it has no other "paperwork" than it's generic part number. I refer you to this weeks Avweb. Rip JohnN3TWN wrote: From: 8300.10 chg 17 - The Inspectors Handbook "(2) Airworthiness: (3) Since “airworthiness” is not defined in the FA Act of 1958, as amended, or in the regulations, a clear understanding of its meaning is essential in conducting a violation investigation. A review of case law relating to airworthiness reveals two conditions that must be met for an aircraft to be considered “airworthy.” These conditions a (a) The aircraft must conform to its type design (certificate). Conformity to type design is considered attained when the required and proper components are installed and they are consistent with the drawings, specifications, and other data that are part of the type certificate. Conformity would include applicable supplemental type certificates and field approved alterations. (b) The aircraft must be in condition for safe operation. This refers to the condition of the aircraft with relation to wear and deterioration. Such conditions could be skin corrosion, window delamination/crazing, fluid leaks, tire wear, etc." part (b) is pretty straight forward although this is the part that open to the most "opinion".....what is ok to one won't be ok to another. Admittedly, most mechanics err on the side of safety here. part (a) states that the aircraft must conform to its type design.....basically, what this means is that the airplane must be in a condition that matches the day it came from the factory -or- be in conformance with applicable STC's or field approvals. The form 337 is the official vehicle that indicates a change from the original type design, that is its purpose. (that’s why its important that the IA doing your annual have all these 337’s available for review). Interpreting further, repairs or alterations that can be construed as minor must be documented in the aircraft records –the catch- here is that these repairs, alterations and the parts associated with them must be shown to be “consistent with the drawings, specifications, and other data that are part of the type certificate”. The big problem here is that most manufacturers will not release the type of information required to make this determination in the field, and even if they did, it would probably require the services of a DER to verify conformity. No mechanics, at least that I’m familiar with are capable of doing an engineering analysis that would satisfy the FAA. So, the next best way to assure conformity is to buy parts from the original manufacturer. They want you to buy parts from them to maintain their products for reasons of liability anyway. Additionally, parts with PMA or TSO approval could (not absolutely would) also be acceptable. Getting back to what got ME involved with this thread from the beginning was a non-standard panel lighting dimmer system. From the definition above it should be very obvious that unless the aircraft is equipped with the system it came from the factory with, it is not considered airworthy unless there is a 337 associated with an STC or field approval for the system installed......because the aircraft no longer conforms to its type design, or quite literally, it doesn’t match the blueprints the manufacturer supplied to the FAA when the aircraft was certificated. This is an issue most owners just don’t understand. I’m not saying that modern PWM dimming systems are bad or good, I’m not saying the original lighting system is bad or good, and I’m not saying that the approval/certification system is fair and just.....I’m just saying that is the way it is. And as an A&P/IA/chief inspector dats wot I godda do! Another issue that I will mention (but I WILL NOT discuss) is the issue of parts for this dimmer system. The regs would imply that the $20 2N3055 transistor from Piper is a suitable replacement part but the $1.50 2N3055 transistor from Radio Shack is not a suitable part. The implication is that the batch of transistors Piper gets, each and every unit is tested and verified to “some standard” whereas the batch that Radio Shack gets has only one in every 10,000 units tested to “some other standard” thus driving up the price for the part the manufacturer sells. The saving grace here is IF the manufacturer lists the part by its generic number in the parts catalog....then the Radio Shack part would probably be OK. This also touches on the issue of owner manufactured parts. FAR 21.303 gives the owner authority to manufacturer parts, however, what makes this impractical in most cases is AC 20-62 which states: "4. DEFINITIONS. The following definitions apply to this AC: b. Acceptable Parts. The following parts may be found to be acceptable for installation on a type certificated product: (1) Standard parts (such as nuts and bolts) conforming to an established industry or U.S. specification. (2) Parts produced by an owner or operator for maintaining or altering their own product and which are shown to conform with FAA-approved data. (3) Parts for which inspections and tests have been accomplished by appropriately certificated persons authorized to determine conformity to FAA-approved design data." The dreaded words “FAA approved data” appear in (2) and (3).....when an owner supplies a mechanic with a part he has produced, he must also supply the mechanic with data to prove compliance with the necessary specifications. How do you get these specifications and how do you show compliance with them? Remember, the installing mechanic has the responsibility to assure the parts he installs meet certain specs.....FAR 43.13 states: "(b) Each person maintaining or altering, or performing preventive maintenance, shall do that work in such a manner and use materials of such a quality, that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition (with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness)." I might make note here that the above excerpt also puts the burden of acceptable parts on an owner performing preventive maintenance. The primary point is that this is why mechanics with a good working knowledge of the FARs will balk when you bring a part to them of questionable origin for installation onto a type certificated product. This brings to mind something that was discussed at great length in this forum....the infamous Yellow Tag. To clarify that point, this document is nothing more than a log book entry when the log books aren’t available. Yellow is the accepted color, but it can be any color you desire as long as it contains the required information and signatures. It doesn’t even have to be a tag. It can actually be a log book entry, it can be an 8 ½ X 11 sheet of paper, it can even be the back of a McDonalds napkin as long as it contains the required information and signatures and becomes a part of the permanent aircraft records. Yes Mr. Weir, I realize that everyone has an opinion and this is mine, as “smelly” as it may be. I welcome you or your General Counsel buddy to cite specific regulatory references that refute my opinion. I may even learn something new. |
#4
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I said I would just mention this and that I didn't want to discuss this. If
you notice I said that there is only an implication of this in the parts sales from the original manufacturer. Regardless what EIA says and does in reference to the transistor, the airframe manufacturer "might" perform their own qualitative testing on said tranistor and if that happens, their testing becomes a part of the TYPE CERTIFICATE DATA. Once that happens, they put a manufacturer's part number on it and it becomes a considerably more grey area if you can use a 2N3055 or Piper part number so and so. Read the entire text of AC 20-62 it does mention "industry standard parts" such as bolts and nuts and even mentions standard electronic parts. Yes, I agree, the manufacturer will sell it at a 100X mark up, the sad part is that I've seen many times they won't even bother to put it in a different box Cheers |
#5
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That would be:
http://www.avweb.com/news/columns/186866-1.html and read the side bar on the bottom right. mark "Gene Kearns" wrote in message ... On Fri, 19 Mar 2004 03:10:30 GMT, rip wrote: Sorry, there is a recent FAA decision that replacement of equivalent parts may be made at the A&P's discretion. An A&P can, in fact, accept a Radio Shack 2N3055 transistor even though it has no other "paperwork" than it's generic part number. I refer you to this weeks Avweb. Rip Can you post this link? I can't find any mention of this in the 3/18 AvWeb or the week preceding..... |
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