bdk wrote:
Jase wrote:
2) If you read the tech orders, they give you instructions on overhauling the engine. IT IS **NOT** LEGAL TO "OVERHAUL" an aircraft engine or accessory unless the entity performing such work (repair station or certificated mechanic) has ALL of the proper & manufacturer required tools and training. For an R-985 or R-1340, those tools include a reassembly jig, which is dang near un-obtainable.
An A&P cannot overhaul an internal supercharger or a planetary gear nosecase. A tech order is only one source of approved data (for an ex-military aircraft in the standard or limited category). The P&W overhaul manual is another. What reassembly jig specifically are you referring to? Plenty of people overhaul R-985's and R-1340's, sending the supercharger out to a repair station for that part of the overhaul. Where does the FAA state that you must have the
manufacturers required tools and training? Aftermarket tools are not OK? A&P school training is not OK?
Jase wrote:
4) ...He *can* make a logbook entry stating that it was torn down, regasketed and reassembled, but he'd be a fool to do so, with no access to a flow bench, knowing that, if there was an accident, the Feds would be asking him exactly what did he do to the carb that he approved for return to service, and oh by the way, how did you flow check it?
What is the requirement to flow check a
float carburetor after reassembly? Is that in the tech order? Carb manual? Will a power check accomplish the same thing?
Jase wrote:
5) I speak from a position of some little knowledge here: If you are restoring an aircraft, the Feds are gonna want to see proof of overhauls of most accessories within the recent past, by an appropriately rated repair station. If you can't show the FAA AI that paperwork, good luck getting a C of A.
Assuming you don't already have one. For a new C of A you need to provide traceability. The aircraft logs are used to provide traceability thereafter. There is also no requirement to overhaul non-life limited components however, they are evaluated based upon condition. There are plenty of aircraft out there flying with 5000 hour accessories- legal, but probably not very smart.
FAR part 43.2, in its entirety:
"Sec. 43.2 - Records of overhaul and rebuilding.
(a) No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being overhauled unless --
(1) Using methods, techniques, and practices acceptable to the Administrator, it has been disassembled, cleaned, inspected, repaired as necessary, and reassembled; and
(2) It has been tested in accordance with approved standards and technical data, or in accordance with current standards and technical data accepteble to the Administrator, which have been developed and documented by the holder of the type certificate, supplemental type certificate, or a material, part, process, or applicance approval under §21.305 of this chapter.
(b) No person may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being rebuilt unless it has been disassembled, cleaned, inspected, repaired as necessary, reassembled, and tested to the same tolerances and limits as a new item, using either new parts or used parts that either conform to new part tolerances and limits or to approved oversized or undersized dimensions. "
I believe, in my own interpretation of the FAR's, that the controlling key here is "...and tested..." in (b). That's my opinion, and as such certainly isn't binding on anyone else.
Regarding O/H of round engines: According to Appendix A of Part 43, separation or disassembly of a crankcase or crankshaft of a reciprocating engine equipped with an integral supercharger is a major repair. Thus, an A&P CANNOT return it to service; only an appropriately rated repair station or IA can do that.
An extract of FAR 43.13: "Each person performing maintenance...shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. If special equipment or test apparatus is recommended by the manufacturer involved, he must use that equipment or apparatus or its equivalent acceptable to the Administrator." So this settles the mfr required tools, and answers the "aftermarket" question. So far as training, if your A&P school curriculum included overhaul or rebuilding of an R-1340, then absollutely you probably "can" do that legally.
FAR Part 65.81 references training and experience:
"Sec. 65.81 - General privileges and limitations.
(a) A certificated mechanic may perform or supervise the maintenance, preventive maintenance or alteration of an aircraft or appliance, or a part thereof, for which he is rated (but excluding major repairs to, and major alterations of, propellers, and any repair to, or alteration of, instruments), and may perform additional duties in accordance with §§65.85, 65.87, and 65.95. However, he may not supervise the maintenance, preventive maintenance, or alteration of, or approve and return to service, any aircraft or appliance, or part thereof, for which he is rated unless he has satisfactorily performed the work concerned at an earlier date. If he has not so performed that work at an earlier date, he may show his ability to do it by performing it to the satisfaction of the Administrator or under the direct supervision of a certificated and appropriately rated mechanic, or a certificated repairman, who has had previous experience in the specific operation concerned.
(b) A certificated mechanic may not exercise the privileges of his certificate and rating unless he understands the current instructions of the manufacturer, and the maintenance manuals, for the specific operation concerned. "
So the key above, is that a mechanic who has never done a given task can *attempt* it, but he CANNOT approve the aircraft/engine/appliance for return to service. If he DOES, then we're back to falsification of records.
I use that as my personal controlling authority on stuff. If you can find the USAAC T.O. on carbs, they reference in it using a flow bench after a teardown/reassembly, even on a float carb. That then, not to mention the liability involved if you happen to misadjust the float, or get the airflow between each barrel unbalanced, is grounds for me personally to send em to an appropriately rated repair station with experience, tools, and competence in the given carb.
And yes, I agree for aircraft flying under Part 91 (General Aviation), there are almost no time limits, it's usually all "on condition". I know a guy who's flying a 1340 with 2000 plus hours on it. Still makes good power and passes all the compression leakdowns, but I'd not trust it personally. It is *legal* though.
Obviously, all of this is one man's opinion, and others can feel free to disagree and have different personal standards, and I won't think any less of anyone who disagrees with me!
Thanks though, bdk, for making me jaunt through the FARs again. Very instructive, and I had forgotten some of what I relearned in this discussion.
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