Charging system failure cuts short a long X-Country

I first flew to Memphis to enter the Memphis 100 race. I did it.

Then on to Atlanta to visit family. The next day I flew to Kitty
Hawk. That was uneventful other than flying over water and
turbulence on approach and departure from the 15 knots gusting 25. An
aerial view is he

http://home.pcisys.net/~ronlee/RV6A/...wkAirSmall.jpg

This is my aircraft with the memorial in the background:

http://home.pcisys.net/~ronlee/RV6A/...roundSmall.jpg

I thought they took off from the hill but no. It was flat terrain
north of the hill. The starting point is he

http://home.pcisys.net/~ronlee/RV6A/...StartSmall.jpg

And the end of the first flight he

http://home.pcisys.net/~ronlee/RV6A/...stEndSmall.jpg

I refueled at an airport west of Kitty Hawk and planned on getting
back to Atlanta right around sunset. Unfortunately, around Rayleigh
the voltage went to just over 12 and the amperage went negative. I
had been hearing a static like popping since leaving Kitty Hawk and
someone suggested that it was arcing from the failure.

I told approach that I was getting lower than the approaching cloud
deck and decided to make a precautionary landing at Sanford NC (KTTA).
No mechanics were around so I got a rental car and went into town for
the night.

The next morning I replaced the voltage regulator with no success so I
removed the lower cowl and found that the battery ring terminal wire
on the alternator B point was fatigued and broken. It was previously
bent to make proper contact.

I had a mechanic install a new ring terminal but that did not make the
alternator work. Using advice from a primo mechanic at home (and not
being able to find a replacement alternator), I bought a battery for
my Blazer, wire, ring terminals and added the new battery in parallel
with my aircraft battery.

Nothing blew up so I prepared to leave. The engine started normally
and to my surprise the alternator worked. It worked all the way home
with four restarts.

On this trip I flew below an overcast with less than 6000' between me
and the ground (perhaps 1500'). I flew over a broken cloud layer.
I flew in less than 100 nm visibility. As I approached Springfield MO
towards sunset, I descended thinking that I was about to overfly a
cloud layer. Nope. It was haze. Silly me. It made more sense to
stay where I could see ground to the sides anyway.

I had planned on going to Key West and the Bahamas but elected to get
home to fix the alternator problem. TS Noel would have kept me from
doing that anyway.

In retrospect, the alternator to bus wire/ring terminal should have
been made better long ago. That will be corrected. I am now in the
process of trying to decide which readily available alternator I will
install. The current one will not fly again.

I also did not know what my safe flying time was when the ring
terminal broke. Perhaps I could have flown another two hours (4-5 amp
current draw and one EI) on a PC925 battery. But since I did not know
for sure, I played it safe and landed at the nearest airport.

With the truck battery, it may well be 20 hours. Regardless, I did
buy a battery charger just in case.

I did find out that the RV community is awesome. Three guys stopped
by to offer assistance (I did the repairs on the ramp). The FBO at
Sanford was great as was the mechanic shop.

Stopping at new airports is fun. I expanded my flight experience
beyond CAVU but nowhere near scud running. The haze illusions were
baffling but I just reacted with safe flight adjustments.

Ron Lee wrote:
In retrospect, the alternator to bus wire/ring terminal should have
been made better long ago. That will be corrected. I am now in the
process of trying to decide which readily available alternator I will
install. The current one will not fly again.

Not that I wish to impose upon your own maintenance decisions or state
that safe is, in fact, not better than sorry, but the alternator may
well be just fine (excepting the ring terminal, of course).

Alternators have to be supplied with a sufficient current from the
battery in order to generate the larger currents required by the
aircraft systems. This is fine as long as the alternator is functioning,
because it is generating enough current to recharge the battery (and
then some). Without that initial current, though, the alternator will
never work, no matter how hard you spin it (a generator, on the other
hand, would).

It sounds as though the ring terminal broke, disconnecting the
alternator, and the battery discharged sufficiently in the intervening
time such that the alternator couldn't achieve a proper magnetic field.
Your mechanic's suggestion to add an additional battery in parallel
provided the system with the amperage it needed, and the alternator
began to work again.

My advice is to have the alternator tested before chucking onto yonder
scrapheap. Regardless, glad to hear you and the aircraft escaped unharmed.

TheSmokingGnu

TheSmokingGnu wrote:

Alternators have to be supplied with a sufficient current from the
battery in order to generate the larger currents required by the
aircraft systems. This is fine as long as the alternator is functioning,
because it is generating enough current to recharge the battery (and
then some). Without that initial current, though, the alternator will
never work, no matter how hard you spin it (a generator, on the other
hand, would).

This may be exactly what happened. The workings of an alternator are
"magic." Since I did have a similar alternator experience where it
would not start once before...and the solution was for an alternator
shop to energize it by touching the "N" terminal I believe with
positive voltage, I did that as well. Either it should have been the
"F" or "E" terminal or I did it incorrectly.

I am changing out to an internally regulated alternator that is easily
obtainable. My current alternator is not either.

Ron Lee

"Ron Lee" wrote

The engine started normally
and to my surprise the alternator worked. It worked all the way home
with four restarts.

Hi Ron,

Thanks for the report of your electrical problem. I always learn valuable
insights from reports like this. Thanks for sharing. By the way, beautiful
RV6!

I'm not arguing, just curious; why replace the alternator if it performed
normally on the way home? I'm no expert, but I wonder if the problem is in
the control circuitry or the old, partially discharged battery. How old was
the battery?

The real expert on stuff like this is Bob Nuckolls at
http://www.matronics.com/Navigator/?AeroElectric-List

Glad it worked out,
Dennis