Slick SB

Discussion in 'Hangar Talk' started by LesGawlik, Jul 21, 2008.

  1. LesGawlik

    LesGawlik Pre-takeoff checklist

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    Product liability law has never been my practice area, but I would guess there are some here who have more familiarity with it that I do. For the life of me, I cannot understand why manufacturers of products made for the aviation market are not held to the same standards as other manufacturers. I understand that the "H" in NHTSA is "Highway" and that the momentum behind an automobile recall is infinitely greater than a few bug smashers. But that doesn't explain to me the phenomenally cavalier attitude of aviation component manufacturers.

    There is the UCC and the implied warranty of merchantability, and/or warranty fitness for a particular purpose. We now learn that almost all of the mags sold by Unison in the last year or so contain defective parts, and could fail after a few dozen hours. They knew about the problem and have yet to do anything except issue an SB requiring owners to disassemble their mags and inspect for incipient failure. Oh, and we get to repeat that process every 25 hours. I've read everything from problems with brushes to the phenolic block which opens the points (Years ago I found out why they put that package of special grease in with new points when I did a tuneup on the Olds with the 455 Rocket engine.) Slick will continue to ship defective mags from stock. There is no solution, but they hope to have a fix in August. There is no clear admission of defectiveness on Slick's part, but the paperwork has escalated to a mandatory SB from Lycoming. It has not progressed to an AD yet.

    I understand that some problems may be revealed by a mag check, but some may not. I may not be as bad off as those who regularly fly at higher altitudes, where carbon tracking from deteriorating brushes may be more of a problem. If you use your aircraft for transportation, the utility is lost when you have to taxi back to the hangar when your new mags fail the runup. If these products were inexpensive, or the technology cutting-edge, I would be a little less disappointed. But these are top dollar items, the technology was mastered in my $99 Wards lawnmower, and the ideas have been around for the better part of a century,

    There is no reason why we couldn't have a class certified in a decent jurisdiction. Why aren't manufacturers held to reasonable standards with respect to design. assembly and inspection? And when defects are found, why is it the purchaser's responsibility to cure the defect, at his expense?
     
    Last edited: Jul 21, 2008
  2. jmaynard

    jmaynard Cleared for Takeoff

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    Is there a list of engines that the affected mags are used on? I'd really get unhappy to find that one of the things I really considered to be a feature about my factory new O-200 was, in fact, a major bug...
     
  3. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Your observation is indeed valid.
    I think it has to do with:
    a) numbers (not enough of us to make a decent size class as in class action lawsuit)
    b) we need them so we put up with that cra@.

    I would like someone to at least make it law that "you can't sell a product with an outstanding AD on it".
     
  4. Dan Thomas

    Dan Thomas Final Approach

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    The mags affected were in a specific serial number range. Your factory -new O-200 is a Teledyne Continental engine, and most likely has Teledyne Continental ignition on it, formerly known as Bendix. Not Slick at all.
    The problem comes, probably, with poorly-trained assemblers in the Unison (Slick) factory. The metal high-voltage output reed on the coil has to be perpendicular to the distributor gear shaft, inside which a spring-loaded cylindrical carbon "brush" fits. This brush runs on the face of the reed, and if the reed isn't bent perpendicular to the shaft/brush assembly, the brush moves around in its bore and wears all funny and cuts a low spot in the reed. The mag could eventually fail.
    We've found four of them, and two needed the coil replaced. We take these things apart every 500 hours like they're supposed to be anyway, and found the first worn pair before the SB ever came out. They had 1000 hours on them. They weren't bad at all at 500 hours. 1000 hours on a "defective" magneto isn't that bad a deal, really, and if the maintenance is being done like it should it would get caught without the SB. After all, the regs require the airplane and its components be maintained in accordance with the manufacturer's recommendations, and Slick's manual calls for 500-hour inspections. Not many get it, I'll bet.
    Slick will replace the defective parts but I don't suppose they'll cover the extra labor.

    Dan
    ________
    GSX-R750
     
    Last edited: Jan 19, 2011
  5. Tom-D

    Tom-D Taxi to Parking

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    Bendix has not made a mag since 1957. TCM engines come new with unison(slick) mags.

    the 500 hour inspection you called out is in a service bulletin, and SBs are not manadtory in part 91. until the SB become an AD or the aircraft or engine manufacturer places the 500 hour requirement on the type certificate the inspection will be optional.

    As it should be.
     
  6. steingar

    steingar Taxi to Parking

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    One of the fellows in my local EAA chapter told me his newly majored engine with the 25 hour SB has bad mags after 5 hours of service (according to his mechanic). He was looking for a ride to Oshkosh because he didn't think he could make the trip (its greater than a 5 hour round trip).

    Someone's going to die. Someone's engine is going to poop out over some sort of hostile terrain, and they're going to die. They're widow, or children, or siblings, or dog or whatever is going to have the mother of all law suits against the company, and when it comes out that they were making defective parts, the survivors are going to win a bazillion dollars and that will be the end of slick.
     
  7. Dan Thomas

    Dan Thomas Final Approach

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    The 500-hour inspection is in the Slick Service Manual, and is often found on aircraft manufacturer's inspection program sheets, too. The 172 manual, for instance, calls for it. It's not in the SB.

    I quote the US FAR dealing with this:

    Sec. 43.13

    Performance rules (general).

    (a) Each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator, except as noted in Sec. 43.16. He 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.

    For us Canadians, we find it in CAR 571.02:
    571.02 (1) Subject to subsection (2), a person who performs maintenance or elementary work on an aeronautical product shall use the most recent methods, techniques, practices, parts, materials, tools, equipment and test apparatuses that are
    (a) specified for the aeronautical product in the most recent maintenance manual or instructions for continued airworthiness developed by the manufacturer of that aeronautical product;
    (b) equivalent to those specified by the manufacturer of that aeronautical product in the most recent maintenance manual or instructions for continued airworthiness; or
    (c) in accordance with recognized industry practices at the time the maintenance or elementary work is performed.



    You can imagine that a lot of airplanes aren't in compliance when it gets right down to it. Many shops don't even have those manuals.




    Dan
     
  8. Dan Thomas

    Dan Thomas Final Approach

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  9. Tom-D

    Tom-D Taxi to Parking

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  10. Tom-D

    Tom-D Taxi to Parking

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    Which 172 manual. ? Because my 172 series service manual 1977-1986 does not mention it. nor does my Cessna 100 service manual.

    The only time you would be required to follow the overhaul manual, or service manual, is if, and when, you open the mag. No body repairs mags in the field, simply because they don't have the tools and or the test equipment to run the mags on the bench.

    Read the FAR 43-D see how many times it requires mags to be opened and inspected during an annual.

    Owners will allow the mag to go to failure, and replace it. why should an A&P require they repair it? If you really want to put your house up for grabs, place a sign off in an aircraft/engine log saying you repaired/worked on the mag.

    Think about it, who can afford the better lawyer, you, TCM, or the widows insurance company.?

    It is the owners responsibility to get all required inspections completed, I would rather the mag be over age, than have my signature in the log saying I tore it apart, and returned it to service.

    AS long as The FAA doesn't think this worthy of an AD I see no reason to panic and tear down any mag.
     
    Last edited: Jul 22, 2008
  11. Tom-D

    Tom-D Taxi to Parking

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    OBTW you quoted the wrong refference..

    It's FAR 43.15

    no where does it say I must disassemble a mag for a timed inspection that is not a time lifed item, or required by an AD.

    Just because it is in a service manual does not make it a required inspection.
     
  12. KennyFlys

    KennyFlys Guest

    Does anyone have any sources for diagrams of the internal workings of magnetos?
     
  13. kmead

    kmead Line Up and Wait

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    When I do maintenance seminars on the Malibu/ Mirage I will tell the owners if the shop isn't willing to open the mags at annual they should at least install rebuilt or new units. You can't believe what we have found inside the mags. We have been finding the cam follower and carbon brush problems for a long time along with gear and points problems too. They normally wont make the 500 hr inspection. If you are inspecting the engine per many factory guides (as the log books state) they will normally ask for items requiring internal inspections of the magnetos.

    As for legal responsibility I'm sure that my neck is way out there, but the practice of opening every mag at each annual will always continue in my shop. If the engine wont start in Bucksnort TN or the engine is damaged by pre-ignition or detonation I'm in trouble too. Eliminate/reduce the chance that the mag will fail on the road (that's our job too) so the owner and passengers wont be looking for another ride home.

    PS. I do have current books, tools, test bench, and a boatload of liability insurance.

    Regards, Kevin
     
  14. Dan Thomas

    Dan Thomas Final Approach

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    Open your manual to page 2-43 and look at line 20. See what it says. Then go to page 2-48 and look at Note K and see what that says.
    It's all there in the manuals, and anyone who doesn't get those mags looked at once in while will experience problems. Slicks will not go 2000 hours without problems.

    Dan
     
  15. Dan Thomas

    Dan Thomas Final Approach

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    Including TCM magnetos, which are the Bendix design and use the old Bendix part numbers. We have one on our R182 and the new engine will have a new TCM mag on it.
    I have a brand-new TCM ignition manual here that covers them all.

    Dan
     
  16. Tom-D

    Tom-D Taxi to Parking

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    where does the FAR 43.13 say I must follow the manufacturers inspection check list?
     
  17. Tom-D

    Tom-D Taxi to Parking

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    I'll give you that one. the last new engine I installed was a IO-550 it came with Slicks.
     
  18. LesGawlik

    LesGawlik Pre-takeoff checklist

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    Okay, but we're drifting a little.

    I don't think it is reasonable to require opening of the mags at every annual, any more than to pull the cam and crank for every annual. Would it be a good thing? Of course, but it is not reasonably required in my opinion.

    I still can't understand why there aren't product recalls at the expense of the manufacturer for aircraft and components, especially for new products. Now when a component is found defective after years or decades of service, it is not reasonable to expect that a manufacturer replace the item at its expense. But when a brand new device is knowingly delivered defective out of the box, something is very wrong. But thank God we're protected from guys selling Ford alternators with 337 instructions. That's where the REAL danger is. The skies would be raining aluminum if they hadn't put and end to that!

    I do know it is not the CPSC's jurisdiction.

    http://www.cpsc.gov/LIBRARY/FOIA/advisory/164.pdf
     
    Last edited: Jul 23, 2008
  19. Dan Thomas

    Dan Thomas Final Approach

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    43.13, here:
    http://www.airweb.faa.gov/REGULATOR...B6AA4758BF91EC0686256A65006FA762?OpenDocument

    The lawmakers enforce compliance by reference, so when they say that you must maintain the airplane in accordance with the latest service manuals, they mean the whole manual, including the inspection checklist. Just try getting past an FAA inspector on it. Here's the quote from 43.13 that regulates by reference:
    "Each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer..."

    The FARs won't mention magnetos or wheel bearings or ailerons or anything else specific when it comes to the huge number of items to be found and inspected in an airplane. They just say "Do it as the manufacturer says" and the lawyers and judges will get you on that if you don't and have an accident or something.

    Dan
     
  20. Dan Thomas

    Dan Thomas Final Approach

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    I don't think the Slick problem is all that big; as I said, we've found four of them, all of them with 1000 hours on them, and still working without misfiring. Maybe the factory sent out some that were really bad and gave a lot more trouble.
    Every annual on an airlane that flies 25 hours a year is a bit much, but an airplane that sits for five years will have corrosion issues in the mags, whether it flew 5 hours or 500 hours or no hours. The mags are at the back where they're cooler, and their front bearings sometimes get moisture condensing in them (from the crankcase gases) that rust them out and cause big failure.
    Most mag problems will show up at runup before flight. The rest, mags that fail in flight, are usually due to not having been opened often enough. If the distributor gears wear, for instance, and slip a tooth or few, the wrong sparkplug will get the spark and will ignite intake gases or fire too early or late or something, making the engine run all stupid. That's what the mag switch is for: To shut off a bad mag if it isn't behaving itself. The switch isn't there just to check mags on runup or to shut them off after the flight or to fill the panel with impressive switches. It can keep you from going down when a bad mag starts igniting stuff when it's not supposed to. Too many pilots don't know that.

    Dan
     
  21. Dan Thomas

    Dan Thomas Final Approach

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    Something on Slicks from Sacramento Sky Ranch:

    http://www.sacskyranch.com/faqslickmagneto.htm

    A description of magneto principles:

    http://selair.selkirk.bc.ca/systems1/Engines/Aircraft Magneto systems.html

    They don't mention all the functions of the condenser (capacitor) in the mag; they only say that it prevents arcing at the points so that they don't burn. This is true, but the magneto won't even produce a spark without the condenser, since arcing represents continued electron flow just when we want it to stop immediately so that the magnetic field collapses as fast as possible to produce the biggest electrical impulse possible. That condenser also, when it begins to discharge back through the primary coil before the points close, gets the flow going the opposite way through the primary, exactly what we want since the polarity of the rotated magnet is going to create flow in that direction anyway. Condenser condition is often overlooked during inspections.
    If you can understand the magneto's workings, you are doing well. Lots of mechanics haven't figured it all out. An understanding of inductors helps, too, since that primary coil creates its own flow after the rotating magnet got it going and has rotated away from the flux frame. The primary's magnetic flux begins to collapse, but this collapse keeps the electron flow going until the magnet is actually a few degrees beyond neutral, when the points open and the biggest flux collapse is possible. "E-Gap," they call that distance between neutral and points opening. If it ain't set right, the mag won't make much spark. I can't find a graph online representing the various fluxes and the E-gap. I have that stuff here.

    Dan
     
  22. Tom-D

    Tom-D Taxi to Parking

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    If you really believe that, think about how many C-100 series or Piper aircraft get way over 100 hours during the year, and never see the A&P to do the 25/50/75/100 hours portions of the inspection check list in the maintenance manual.

    No...... because Cessna or Piper can not dictate maintenance beyond what the FAA requires.

    I believe you have a misunderstanding of the inspection requirements and maintanence requirements given in the regulations.

    The FAA does not consider these aircraft inspected IAW FAR 43-D Scope and detale of an annual/100hour unairworthy due to the inspecting IA has chosen to not use the check list given in the maintenance manual.

    Until the FAA issues the AD requiring this inspection at 500 hours, it will not be a required inspection.

    I believe you havea misunderstanding of maintanence and inspections. because you left out

    "
    You left out the important part.
    (c) Annual and 100-hour inspections. (1) Each person performing an annual or 100-hour inspection shall use a checklist while performing the inspection. The checklist may be of the person's own design, one provided by the manufacturer of the equipment being inspected or one obtained from another source. This checklist must include the scope and detail of the items contained in appendix D to this part and paragraph (b) of this section.
     
    Last edited: Jul 24, 2008
  23. Tom-D

    Tom-D Taxi to Parking

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    Dan,,,,, do you fully understand the working of the mag?
     
  24. Joe B

    Joe B Pre-takeoff checklist

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    Let me see if I've got this straight: the manufacturer doesn't know how to fix the problem but you want them to do a product recall anyway. After you send your potentially defective product back to the manufacturer, then what? Watch the grass grow at your tiedown while you wait for the manufacturer to come up with a fix?
     
  25. Dan Thomas

    Dan Thomas Final Approach

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    I teach this stuff in a College setting. I've had to do a lot or research, and also maintain all the flight school's airplanes.

    Dan
     
  26. Tom-D

    Tom-D Taxi to Parking

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    Please explane to me how a Bendix VN7DFA mag can be timed to a 7 cylinder radial engine when the mag has only 4 lobes on the point opening cam. and can fire the engine every 103.3 degrees while at cranking speeds with out a impulse coupling.

    And this same auto advanced mag can be timed to the engine at 28 degrees. with out kicking back on the starter.
     

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    Last edited: Jul 24, 2008
  27. Dan Thomas

    Dan Thomas Final Approach

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    I haven't run into that one, but it probably has either Bendix's shower of sparks system that uses two sets of points and the vibrator input for starting, or the Lasar system that uses the same idea, with electronic controls and variable timing to improve performance and eliminate the impulse coupling.
    Gearing of the mag can run 4 lobes to fire seven cylinders, but many mags on radials have odd lobe heights to vary the ignition firing to allow for the elliptical rod travel (and therefore the piston location) on all but the number one rod. Four lobes wouldn't work for that; you'd need a lobe for every cylinder.

    As far a mag inspections on annuals go, they could be seen to be covered by FAR 43.15 Appendix D (referred to in 43.15(c):
    (c) Annual and 100-hour inspections. (1) Each person performing an annual or 100-hour inspection shall use a checklist while performing the inspection. The checklist may be of the person's own design, one provided by the manufacturer of the equipment being inspected or one obtained from another source. This checklist must include the scope and detail of the items contained in appendix D to this part and paragraph (b) of this section.

    Appendix D excerpt:
    (d) Each person performing an annual or 100-hour inspection shall inspect (where applicable) components of the engine and nacelle group as follows:
    (1) Engine section--------
    (10) All systems--for improper installation, poor general condition, defects, and insecure attachment.

    Canada has similar provisions but most here use the manufacturer's checklist, since the reg does not allow the use of the appendix itself as a checklist. The government will allow, if a good case can be made, variations from the manufacturer's requirements, some of which are far too onerous.


    Dan
     
  28. Tom-D

    Tom-D Taxi to Parking

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    No shower of sparks, no impulse coupling, one set of points.
     
  29. Tom-D

    Tom-D Taxi to Parking

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    In the US we are allowed to copy the list in FAR 43-D and use it as our inspection check list.

    Where did you get the notion that we couldn't?

    Tom Downey A&P-IA
     
  30. gprellwitz

    gprellwitz Touchdown! Greaser!

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    Tom, I think "here" refers to Canada; he's saying the Canadian regs prohibit that.

    All I know is that when all else fails, "reverse the polarity of the Neutron flow!":goofy: -- The Doctor
     
  31. jmaynard

    jmaynard Cleared for Takeoff

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    Grumble. I wrote down the numbers on mine when I had the cowling off for the 50-hour maintenance yesterday. Guess what? My factory new O-200 has Slick mags that are affected by both of the service bulletins. &**%^&*$^&(.
     
  32. Tom-D

    Tom-D Taxi to Parking

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    Remember,,, the service bulletin is not mandatory in part 91. as long as they run well, don't fix what ain't broke.
     
  33. jmaynard

    jmaynard Cleared for Takeoff

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    Yeah. OTOH, sounds like something that'll get checked at the annual next June, unless it acts weird first...