Today's Message Index:
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1. 07:16 AM - Re: Factory Certified but is this safe? (Michael Wynn)
2. 07:01 PM - Re: Factory Certified but is this safe? (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Factory Certified but is this safe? |
In looking at the original published plans, the starter contactor next to t
he battery and no master is what is published.=C2- I am working with my A
&P to sort out the legalities of the situation but my decision is to rewire
using the Z11 basic form.=C2- I changed out the alternator for the TSO'd
version of the B&C 40 amp alternator and LRC-3 regulator.=C2- In my view
, safety trumps legality.=C2- I cannot explain how the type certificate w
as approved this way but the original design was from the 1940's and I'm no
t sure when the type certificate was given.=C2- It certainly wouldn't pas
s at present.
I have a call in to Aviat to see if there is a service bulletin or somethin
g that allows me to legally make the changes.=C2- Beyond that, safety fir
st is the byline.=C2- If I need the 337, then we will get that done.=C2
- I cannot believe I am the first Pitts owner to encounter this situation
.=C2- Thanks for the feedback.
Regards,
Michael WynnRV8Pitts S1-SLivermore, CA
-----Original Message-----
From: Robert L. Nuckolls, III <nuckolls.bob@aeroelectric.com>
Sent: Thu, Jun 20, 2019 5:56 pm
Subject: Re: AeroElectric-List: Factory Certified but is this safe?
At 08:16 PM 6/18/2019, you wrote:
Hi all,
I am rebuilding and restoring a 1977 factory certified S1-S Pitts.=C2-The
electrical system is pretty basic but there is one aspect that I amtrying
to understand.=C2- The battery is located behind the pilot'sseat.=C2- T
here is a contactor directly adjacent that energizes thestarter.=C2- Ther
e is a large wire, #8 or so, that goes from thebattery that goes down the f
rame to the console between the pilot's legswhere the circuit breakers and
switches reside.=C2- That wire goes intoan ammeter and from there to the
main bus, on which the various circuitbreakers reside.=C2- There is no fu
se, contactor or other circuitinterruption device between the battery and t
he console.=C2- If thatmain feed wire were to erode through or otherwise
short, there would benothing to stop the welding action until the battery d
ied.
I wired my RV8 per the excellent instructions in the AeroelectricConnection
.=C2- I feel quite safe about it.=C2- There is a very shortrun between
the batter and the main contactor but all other wires areprotected.=C2- N
ot so with the factory Pitts wiring.=C2- Should I beadding a fuse or cont
actor or something near the battery to protect thiscircuit?
=C2- Do you have a schematic of the system?
=C2- How big is the alternator/generator?
=C2- I am surprised that a type certificated
=C2- airplane would be configured as you've
=C2- described because it does not comply
=C2- with Part 23 rules for crew management
=C2- of power sources.
=C2- You could add a battery contactor for
=C2- just that feeder . . .but if you're
=C2- going to add ANY contactor, why
=C2- not wire per 99.9% of other TC
=C2- aircraft?
=C2- Add a legacy battery contactor
=C2- upstream of the starter contactor
=C2- then move the 8AWG feeder to
=C2- the junction between those
=C2- contactors. Of course, you'll
=C2- need to add a battery master
=C2- to the panel.
=C2- What's your situation with respect
=C2- to 'mods'? Do you need to execute
=C2- a Form 337 Field Approval?
=C2-=C2-
=C2- Bob . . .
Message 2
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| Subject: | Re: Factory Certified but is this safe? |
At 09:15 AM 6/23/2019, you wrote:
>In looking at the original published plans, the starter contactor
>next to the battery and no master is what is published. I am
>working with my A&P to sort out the legalities of the situation but
>my decision is to rewire using the Z11 basic form. I changed out
>the alternator for the TSO'd version of the B&C 40 amp alternator
>and LRC-3 regulator. In my view, safety trumps legality. I cannot
>explain how the type certificate was approved this way but the
>original design was from the 1940's and I'm not sure when the type
>certificate was given. It certainly wouldn't pass at present.
Yeah . . . that would have been a CAR3
rules. I'll have to see if I still have
a copy of the light-plane rules in
my archives. I would be interesting
to see what was required back then.
>I have a call in to Aviat to see if there is a service bulletin or
>something that allows me to legally make the changes. Beyond that,
>safety first is the byline. If I need the 337, then we will get
>that done. I cannot believe I am the first Pitts owner to encounter
>this situation. Thanks for the feedback.
Is there a type-club that might
have exemplar 337 submissions
that were successful upgrades?
Barring that, consider a
337 that cites an 'upgrade
to the original system with:
(1) architecture patterned after 1968 C172
(2) fully compliant with FAR23 paragraphs
23.1351 thru 23.1367
(3) installed per practices described
in AC43-13 and all applicable
manufacturer's recommendations.
Then attach a drawing of the system (should
be pretty simple). Break it up in page
per system format like that found in the
back of the various Cessna service manuals
available from my website.
I know a DAR type that could help
you craft the document.
Bob . . .
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