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Some general maintenance tips from Mike Busch

C210_Flyer wrote:

Im going to have to have my mags OH as per scheduled hrs which everyone one Ive talked to said it is required. Im going to ask for a quote for R& R and overhaul. Im wondering if they will do it. By the way This is a pretty straight forward out and in. I know the points have to be replaced and a NYLON gear but I wonder what else is done during a Mag Overhaul?

Most shops should be able to give you this information. Depending on the type of magento’s, points, felt strip, felt washer, hardware, impulse coupling spring, bearing, are replaced. Coils and capicators typically get measured. For example, shorted and open coil windings would in many cases be unnoticed by the pilot, as the output will still be sufficient (and the voltage high enough to jump the gap in an open). These coils get replaced as well. On some magneto’s (Bendix S4 / S6 / duals) the housing need to have the paint removed, fluorescent pentrant inspection carried out, repainted etc. On the big 1200 series this isn’t an issue.

I have done quote some work in an component shop environment, at a shop which does most components for Dutch aircraft. I can not understand why you want to send them away. Especially factory overhaul is quite poor quality. You would get better results from the shop I worked from, as well as from several other European shops.

JP-Avionics
EHMZ

wigglyamp wrote:

The problem for the maintenance company is knowing how far to go in initial diagnosis before presenting an estimate for a repair, knowing that the customer is looking normally for a cheap and quick fix

Agree. Yet their are many companies out there who don’t analyze anything, and just starting swapping components. Here is an alternator a good example, aircraft lost charge during flight. Often the Alternator gets tossed out as it doesn’t have an output, then the voltage regulator, only to find out something else was broken (over voltage protection, or circuit breaker or wiring).

Troubleshooting and diagnostics is important and cost some money, on the long run it will be more economical then just swapping components.

JP-Avionics
EHMZ

There are very good angles here.

However, as an owner since 2002, I think there are many issues which are structural to the GA business. The biggest one is a dire shortage of technical expertise as soon as you get away from something simple and mechanical.

Wigglyamp’s autopilot example is right at the far end of the scale, with the number of people in the UK avionics business who understand an autopilot being countable on 1 or 2 fingers. Consequently a large % of autopilots don’t work. Sometimes this is formalised with an “INOP” sticker… I have long ago lost count of UK aircraft owners whose autopilots have not worked for as long as they can remember. Yesterday I met one whose AP works in HDG (or maybe just ROL) but not NAV, though I think that was a syndicate plane.

Right now I have a starter motor (Skytec 149NL) which makes a funny grinding noise, for a second or so, before it eventually engages. It was fitted in 2008 after this episode which was also a fine example of a total lack of troubleshooting expertise. It could be the starter or it could be the relay, which is an untraceable Valeo 24V truck part which has to come from Socata (if you want a lookalike replacement, otherwise a common Stancor part will be fine). I have no maintenance facilities at my base so will just exchange the starter (200+ quid) and see. At that cost level, and with the hassle of removing the cowlings outdoors (not allowed to work in the hangar) it’s not worth spending too much time, with an oscilloscope on the starter motor terminals to see if the relay contacts are shagged and intermittently dropping out… And I don’t think any maintenance company would do anything different. Let’s face it, even Socata itself didn’t (see the link).

Nobody could quote a fixed price on a job like that, obviously.

In the end it comes down to what facilities one has and what relationships one has with maintenance people. Sometimes, especially for owners who do their own work, relationships with companies are hard to maintain…

And when somebody does a Grade A bodge then you probably won’t use that company ever again (who would?) and the number of options is reduced by one each time that happens.

Administrator
Shoreham EGKA, United Kingdom

Jesse wrote:

I have done quote some work in an component shop environment, at a shop which does most components for Dutch aircraft. I can not understand why you want to send them away. Especially factory overhaul is quite poor quality. You would get better results from the shop I worked from, as well as from several other European shops.

I try not to send anything to the factory. Most of them over charge by a lot.

I have a Bendix 1200 mags who does a quality overhaul for a reasonable price? I give them a call.

KHTO, LHTL

wigglyamp wrote:

However, if you have a defect like porpoising in pitch on autopilot, then it becomes much more complicated. You could have a stiff flying control bearing, tight pulley, wrong cable tensions, weak servo, slipping clutch, faulty gyro, defective computer etc. So who should pay for the diagnosis and how long should be spent before getting the customer’s agreement on a potential component change? There’s no simple answer and often the maintenance company ends up writing off fault-finding time which should really be chargeable.

Your statement illustrates my point.

I had that porpoising autopilot for which I went back numerous times. It would work for 2-5 flights and then come back. Kinda like a volcano. Lays dormant for years then explodes.

KHTO, LHTL

C210_Flyer wrote:

I have a Bendix 1200 mags who does a quality overhaul for a reasonable price?

And what do you consider to be a reasonable price ?

FAA A&P/IA
LFPN

Peter wrote:

Nobody could quote a fixed price on a job like that, obviously..

They probably could and or did, but since they would be CYA, you would not want to pay the price.

In the end it comes down to what facilities one has and what relationships one has with maintenance people. Sometimes, especially for owners who do their own work, relationships with companies are hard to maintain…

+1

And when somebody does a Grade A bodge then you probably won’t use that company ever again (who would?) and the number of options is reduced by one each time that happens.

The sad truth.

FAA A&P/IA
LFPN

And what do you consider to be a reasonable price ?

I don’t know about the 1200 but I pay about $800 plus shipping and VAT to QAA at Tulsa, for a D3000 single shaft dual mag overhaul.

Last UK price was GBP 800 so probably similar but that was the con-job company who refused to give me the work pack afterwards, so I had to send the mag to QAA anyway, and they pointed out various issues including almost certainly secondhand components. I have recently been informed that the owner of that company is no longer there (it was taken over by another one).

The sad truth.

I don’t like to ever use again a firm who buggered me around (and same goes for individuals) but you would be amazed at how many people do continue to use these firms. But I think often it’s because most owners never find out what was done or not done.

Administrator
Shoreham EGKA, United Kingdom

Is Busch’s book “Manifesto” (mentioned at the end of the article) worth getting or any other suggestion?

CKN
EGLM (White Waltham)

CKN wrote:

Is Busch’s book “Manifesto” (mentioned at the end of the article) worth getting or any other suggestion?

Basically a collection of past articles, so if you haven’t read or don’t have access to the dozens of pieces he’s written over the years, or just to have it all under one cover, then yes it would be a good buy, particularly for an owner/operator who wants to be “involved” with MX.

FAA A&P/IA
LFPN
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