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tennesseect

Lost all electrical instruments

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Monday I lost all electrical instruments about 80 nm from home at 5500 feet.  I was returning to Nashville from Illinois in my 2007 CTsw after having a defective EGT sensor replaced.  Partway home the ALTERNATOR warning light and buzzer started going off.  Because of previous bogus warnings I'd been getting from my Dynon EMS, I convinced myself to once again just push 'Acknowledge' and press on.  I've also had intermittent Alternator warnings when throttling back for landing, but they would subsequently go away.   I couldn't believe the battery voltage and charging current was actually slowly falling through the yellow band into the red.  But shortly after checking in with Campbell approach to continue flight-following the Dynon screens began fading to black.  Every few minutes the voltage returned enough to hear Campbell approach asking 'How do you read?'.  My radio wouldn't transmit so I decided to switch my squawk code to 7600.  Naturally I was racking my brain as to what I should do next.  I didn't panic since I had analog back-up instruments for airspeed, altitude and compass heading.  The weather was VFR and my Rotax was purring contentedly.  I had my iPad with Foreflight with me, but the battery life of my iPad was down to only 20-some percent.  The 30 knot tailwind I had in the morning was now a headwind so I had turned off the iPad to save the remaining juice for my approach to my home base at Nashville's John Tune.  Since last year's tornado I've not only been without a hangar, but the traffic at Tune has seemingly doubled.   I guess those jet-jockeys prefer landing straight-in at a non-towered airport to all the rigmarole and higher prices at BNA.  A tower has just been built but it's not yet operational.  Tune is no longer a safe place for light-sport airplanes to land with neither a radio nor traffic info.

I wondered if my flaps were going to work, so i switched the knob back and forth a few times - to no avail.  I had never attempted a landing with flaps at -6.  A scratchy voice again came oveer my headset instructing me to squawk VFR.  After complying, I began hearing a loud screeching in my hedset.  The noise was even louder when I took off my headset - so I put it back on.  After a moment I noticed the flaps had moved to 15 and my airspeed was well above the 80-kt limit.   The flap control again wouldn't work so I throttled back, resigning myself to a slow flight home.

I turned Foreflight back on within about 20 nm to observe traffic using my  portable ADS-B receiver.  I manuevered so as to avoid both straight-in jet traffic and other traffic using the pattern, entering the downwind on a 45 and slipping in behind a C172.  No sweat!  After landing I never heard a peep about some jerk who landed without making a single position announcement.

I took the battery out of my CT and charged it at home with my trickle charger.  By the next morning it indicated fully charged.  After reinstalling the battery I did a ground check.  The Rotax fired right up and all looked well for a few minutes.  But then the battery voltage and amperage began another slow decline into the yellow band - even at 2600 RPM  I tried pushing and pulling the alternator master switch a couple of times and didn't see any change in the instrument readings.  I surmise the problem lies in one of five places:  the circuit breaker, the wiring, the rectifier, the regulator, or the alternator itself.  Can anyone tell me how to proceed with troubleshooting?  Help!

 

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Thanks for the pirep.  I don't have anything to add but appreciate the report.  Helps us all learn.

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Quite a story ...  as I always keep reminding people, whatever you do , don’t go to Illinois , nothing good will come out of it ....

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I ran into an issue a few months ago, when it was exceptionally cold for here, where the alternator refused to turn on.  Me and a local mechanic friend did some troubleshooting with a multimeter, and after about 15 minutes, he thought about reseating the connector on the regulator.  Fired up the engine and it worked great.  That is the second time in as many years that has happened.  Not sure why it does that though.  Might be worth trying.

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I had to replace my voltage regulator when it finally stopped bringing the alternator in to  charge the battery.   It would take longer and longer for the voltage to pop up into the charging range. 

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Done my regulator couple of times unhook it wiggle a little bit put it back on check

for burnt place inside plug you should be working again maybe.Dielectric grease to.

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Like other said, probable a bad regulator, mine went out last year.  It was in and out or a few months prior, I used some contact cleaner spray to get the contact cleaned and dielectric grease to seal things up.  When I replaced it I made sure to give it some grease to prolong the connections.

 

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21 hours ago, tennesseect said:

Is dielectric grease something readily vailable at say an auto parts store?

yes it is, usually in the same section as fuses, bulbs, wire, etc..  I've always picked mine up from Amazon when a tube gets low.  I bought an old Ford Excursion that suffered some electrical gremlins all from corroded connections.  Contact cleaner and grease have become a regular use item, have a small amount of both in the console at all times.

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23 hours ago, tennesseect said:

Is dielectric grease something readily vailable at say an auto parts store?

Called bulb grease at an auto parts store.

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Hello,

I fly a 2002 CT2k in the UK and had a similar problem last year.  Complete electrical failure without warning, and a very low voltage battery once removed after landing.

Battery replaced, all seemed well for a few more hours flying when the same happened again, and I noticed that the 30 amp charging circuit breaker had tripped.

I ordered a new breaker and when changing it did a careful inspection of the wiring ...sure enough, an almost invisible nick in one of the wires to the breaker...it looked like it had been caught or chaffing on the carbon binnacle behind the panel which, in places, is razor sharp at the edges.

Since carbon conducts, this was a ground short pulling over 30amps....so i'm very grateful for the breaker being there!

As the tripped breaker would have meant no power from the engine running the electrical systems or recharging the battery, these systems (IEfis, transponder, radio/intercom, strobes, iPad, flaps etc) would have been running solely off the 5ah lifepo4 battery until it depleted, causing the subsequent complete power failure in flight....probably around 30-40 mins after the breaker tripped which happened without me noticing it...and most likely happened on takeoff from my slightly rough grass strip.

 

I replaced the breaker anyway with new since I'd already bought a new replacement, and had plenty enough length of wire just to trim back slightly removing the split section of tefzel wire. 

I have had no further problems since.

Hope this info helps somebody...image of the wire I found is attached.

 

 

IMG_20200829_164612530.jpg

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12 hours ago, SteveC said:

sure enough, an almost invisible nick in one of the wires to the breaker...it looked like it had been caught or chaffing on the carbon binnacle behind the panel which, in places, is razor sharp at the edges.

There was an AD regarding a precautionary fix a while back about this phenom.  The potential problem area was the wire bundle that enters the dashboard area through the firewall.  The AD called for a wrapping of the wire bundle with that orangy /brown colored silicon tape.  I did it, and, I covered a bundle in the baggage as a just in case measure.  I have a CTLSi perhaps the AD only applies to that model.

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AD is a term that normally applies to standard category aircraft, though in some cases can apply to any aircraft. For SLSA aircraft the proper term is Safety Directive. Flight Design uses the term Service Bulletin, which can lead to confusion among mechanics who live in the standard category world. You have to dig a little on Flight Designs website to see the for them a SB is just one level of safety directive. I asked a mechanic who had performed an inspection on a CTLS whether they had complied with a couple specific SB's, and she said that SB's were not mandatory. 

Anyway in the case of this issue it is a SB, which is really a SD, and not an AD.

There is one AD that applies to many CT's, and many mechanics miss it when doing an inspection.

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Well I believe I've fixed the problem - by replacing the voltage regulator.  I cleaned all the contacts with a wire brush and some electronics spray cleaner as some of you advised and applied dieletric grease to the contacts with a toothbrush.  I ran the Rotax on the ground for 20 minutes and flew around the pattern for another 20 minutes.  The EMS now indicates a steady 13 volts and the amperage stays in the green arc.  Thanks to all for your advice!   Going forward I will pay closer attention to voltage  and current readings and especially to warning lightsand buzzers.

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