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Standby / backup alternator for the TB20 (and other types)

I don't disagree but it had too low a capacity for a glass panel aircraft. Pragmatic is fine but it has to do the job.

EGTK Oxford

Can you post any details, Jason?

Administrator
Shoreham EGKA, United Kingdom

The Concorde eligibility list lists equivalent Concorde batteries for Piper Parts Numbers. After serial number 4636375 in the PA-46 Mirage when the glass cockpits were put in, the battery part number changed (needing a higher capacity battery). I understand a lot of people put the Concorde battery in thinking it was a replacement - as did my previous owner.

I actually now have a Concorde battery (RG24-17) in but to fit it you need a fitting kit due to its different size.

I am not criticising Concorde just saying you should be very careful before blindly following company brochures on what is a correct replacement for something as important as a battery.

EGTK Oxford

OK; there is plenty of that kind of stuff.

Like a starter motor mfg having a PMA for starters which draw ~ 2x more current than the original ones They work but they expose certain "issues" in certain airframes...

A while ago I bought some air filters (big American automotive name; forgotten it now) which were STCd for the TB20. They didn't fit, and it turned out the STC holder was unaware of air path changes in various TB models. I got my money back (a year later) but, yeah, nobody knows everything, not the FAA and not EASA. It's clearly possible and it will always be possible to get an STC which is utterly bogus.

In your case, Concorde should have made their recommendation S/N-specific.

EASA just love cases like that to "prove" that Europe is better.

But then so much stuff works on trust. When say Cessna collect flight test data on a new aircraft, they don't have an FAA rep sitting there watching the data, and then taking away the data loggers etc to check their calibration.

That is what results in stuff like this which is the most atrocious example I know of.

Administrator
Shoreham EGKA, United Kingdom

As a follow up to this thread, I have been watching my current draw with normal flight instruments and accessories being used. I a am only drawing 67 amps with all three screens, dual Garmins, pitot heat and low windscreen heat. Consequently with dual 75 amp alternators I feel good about the aircraft's capabilities if an alternator fails.

EGTK Oxford

What is the breakdown of the 67 amps? It seems a lot of current. My TB20 draws of the order of 10 amps, plus the pitot heat which draws something like 15 amps. I have a 28V 40A ground power unit which has a current readout and that comfortably powers the aircraft with everything on.

Administrator
Shoreham EGKA, United Kingdom

Well the heated windshield will be nearly 20. Will do a breakdown when next back in the UK and flying the plane.

EGTK Oxford

It would be very interesting to see that.

How many Ah is your battery?

Administrator
Shoreham EGKA, United Kingdom

It is a 16 Ah battery.

EGTK Oxford

What would be involved, paperwork-wise, in installing one of these, on a single alternator aircraft, to power just some avionics? (N-reg)

To get it in as a Minor modification, one would need to be able to justify it as not a "basic change to the electrical system".

Otherwise, given there is no STC for the TB20, it would be a Field Approval i.e. a lot of work.

The way these work is quite interesting. You get a flashing warning until you load shed enough to get below the 20A rated output.

Administrator
Shoreham EGKA, United Kingdom
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