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Fitting FAA TSO'd Tachometer to D reg (EASA) Aircraft -whats involved?

I was merrily flying from Leipzig (EDDP) to Lognes (LFPL) the other day when I noticed the tachometer / RPM indicator in my mooney jumping about a bit. At this point i took a little video of it planning to post it here for opinions when back on the ground. Ive tried to attach the video here


for those interested.
A while later, it started to make a hell of a buzzing noise, which I could feel in the instrument with my fingers on the glass. The bouncing needle became extreme -from max to min, back and forth. The buzzing noise reached its peak, then became intermittent before stopping altogether more or less at the same time that the vibration in the instrument caused the needle to fall off its post.
I was mostly confident this was an indicator problem and that the engine /prop were secure but as I was passing Hangelar (EDKB) and was concerned about the noise and the possibility of power loss (which turned out to be a false fear), I called a PAN and made a precautionary landing at EDKB (which was closed-thats another story) and all was fine in the end once safely on the ground.

So the nice folks at Fleuzeugwerft Moeller are going to take a look at the problem -at present its unknown wether the problem is with the mechanical taco cable or the indicator or both. They have some repair capability on site for the cable and the instrument but Ive been researching the options in case one or other are wrecked.

My preferred option would be to replace the indicator with an analogue electronic tach like this one. If the link doesn’t work, try this one,
It uses the standard Tacho port on the engine but converts this to an electrical signal (rather than a mechanical cable) and the fit will be much easier than a new mechanical cable. I prefer this analogue display to the ones with a digital readout or lots of LEDs (like the horizon or EI taco series). I understand that the digital display systems have more functionality -but I’m not bothered about that much.

So to my question….
These tachometers are a recognised fit for moneys and many other aircraft in the US and are FAA TSO’d with an STC for it. The company website doesn’t mention EASA STC or ETSO paperwork. Does this mean fitting such an instrument is a non starter? or can the maintenance shop write a local STC for it (how long might that take /who much might it cost?). I tried to have a rummage on the EASA website to see if there might be any STCs already existing for a new tat- but I couldn’t see any ( though it is an impenetrable website)

Has anyone any experience of replacing a tacho in an EASA aircraft? What route did you go down, which device did you choose?

I suppose the base position (if the current kit is beyond repair) is to source a replacement cable and indicator either direct from Moooney (assuming they can /will supply) or a second hand ‘working used’ indicator (with some kind of shop generated Form 1 release to service) to avoid any paperwork pitfalls with these other instruments i.e. try to replace ‘like for like’ – even though these later generation tachos may be superior to the original mechanical ones.

Any thoughts comments opinions gratefully received..

Last Edited by Justin at 04 Jan 13:07
EGNV and Fishburn Airfield

Does this mean fitting such an instrument is a non starter?

Pretty much so.

or can the maintenance shop write a local STC for it (how long might that take /who much might it cost?).

Others can advise much more in detail, but in short: yes, it would cost a load of money.

I tried to have a rummage on the EASA website to see if there might be any STCs already existing for a new tat- but I couldn’t see any ( though it is an impenetrable website)

That’s part of the problem.

made aprecautionary landing at EDKB (which was closed-thats another story)

Please tell us that story!

Last Edited by boscomantico at 04 Jan 13:34
Frankfurt (EDFZ, EDFE), Germany

Under FAA there is a general principle that providing you do not remove an existing instrument which is required as per the Type Certificate, you can fit a TSOd instrument which duplicates it. It has to be an indicator only i.e. no autopilot connection, etc.

I would be surprised if EASA did not have a similar concession.

The problem with flying with a duff original RPM indicator is that you won’t get the next Annual signed off, so you still need to fix that one, unfortunately.

Administrator
Shoreham EGKA, United Kingdom

It is most likely that the cable is bad. Should the indicator be bad you have the option to have have it repaired (not sure if it would be repairable) or renewed by the same P/N. Another partnumber requires an EASA approval. An EASA approval could be a full “STC” or a minor change approval. A full STC can only be done by a Part 21 DOA. This approval is quite expensive, so is the work that is carried out by these companies. I don’t see a reason why this would be a major, which is more affordeable (EASA fees around 290 Euro plus cost to make this paperwork). Depending on the cost it might be most economical to replace it with the same P/N.

JP-Avionics
EHMZ

Hmm thanks Guys. Especially to you Jesse. Looks like a part number like for like swap at least will be the easiest solution. Out of interest- how long does it take to get a minor mod done? presumably EASA needs to review the plans before accepting them? (i.e. weeks would be the timescale rather than days).

Bosco,
As for the out of hours landing, Im my experience, German regs are a bit sensitive when it comes to TO or landing at an unmanned airfield. I know it varies state to state but when I once hangared my aircraft in Merseberg (Sachsen Anhalt), I had to ring someone to come and sit on a chair at the airfield whenever I wanted of catch a quick flight on a pretty summers evening. Same for landings too. Quite unlike at my then base airfield- a grass strip in NE England where I came and went as I pleased- often quite alone.
Anyway – Langen radar were rather keen that I flew to Koln-Bonn (fairly making the point that there was fire and rescue avail there etc) rather than the nearest which was Hangelar (but was closed). I did query with them that I thought I could land at a closed airfield in ‘urgent circumstances’ to which he went off air, spoke to colleagues and came back saying they ’weren’t sure’ if i could land at a closed airfield’. As I approached Hangelar, I took matters into my own hands and decide against flying past it and told then man that as I was uncertain of the power output /chance of power loss, i was declaring a PAN, would overfly the closed airfield and if the runway was clear- make a precautionary landing. I cancelled IFR (in fact the whole flight plan) kept him on radio all the way down and told him when we’d safely landed. He told me as a matter of course, as Id landed at a closed airfield they’d called the local police. Sure enough, half an hour later, they turned up, took a statement, had a look at the Tach needle lying in the bottom of the instrument, took some pics of the A/C reg document, my details, passport data, address and then seemed happy enough and left. Luckily a guy for the airfield turned up by chance (who was also a pilot) who was helpful in explaining to the police that the precautionary landing was reasonable in the circumstances and all seemed happy that using a closed airfield in this circumstance was OK.

EGNV and Fishburn Airfield

regs are a bit sensitive when it comes to TO or landing at an unmanned airfield

Well put. It’s one of the holy grails of German air law…

when I once hangared my aircraft in Merseberg (Sachsen Anhalt), I had to ring someone to come and sit on a chair at the airfield whenever I wanted of catch a quick flight on a pretty summers evening. Same for landings toO

I know and it’s a shame. Like you, most British pilots flying in Germany for the first time almost can’t believe that. But it’s true. These rules date back to the 1930s and were never abandoned…

spoke to colleagues and came back saying they ’weren’t sure’ if i could land at a closed airfield’.

That’s even more of a shame. Every controller should (must!) know that precautionary landings are allowed on any airfield. It almost seems like he wanted to stop you from going there! They really ought to know better. The problem is: these radar controllers very rarely deal with such problems (small aircraft having to do precautionary landings at “closed” airfields and such), but still: very poor performance on their side.

He told me as a matter of course, as Id landed at a closed airfield they’d called the local police

For all I know, he was not legally required to. Certainly OTT. Anyway, according to German air law, from your side, the only thing you should have done is inform the airfield operator before you took off again. That’s it.

Sure enough, half an hour later, they turned up, took a statement, had a look at the Tach needle lying in the bottom of the instrument, took some pics of the A/C reg document, my details, passport data, address and then seemed happy enough and left.

Bad stuff. What can happen is that one of those “officials” ponders that since you that you had a technical problem to start with, and since the problem is still there, departing again would be dangerous and can not take place until it is repaired and a maintenance inspector or whatever has declared that the problem has been solved. Don’t laugh at me, this is how Germany works sometimes… Therefore: never tell / show anyone anything inside your aircraft, particularly not any defects (unless the person is clearly entitled to see these things). Never tell ATC about any malfunctions on board. It helps nothing and may only get you into paperwork troubles later on.

But it sounds like luckily you got away more or less.

Last Edited by boscomantico at 04 Jan 22:16
Frankfurt (EDFZ, EDFE), Germany
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