Loss of electrical...

[eriknorth]

At the flight school I fly from, the 172 that I fly keeps having problems with the voltage regulator, which causes a discharge, and an eventual loss of electrical. One of my friends took a flight and was actually getting excessive charge, and after reading a bit in the POH, he turned on more equipment to keep it down. They soon after encountered a discharge and had to keep the electrical at a minimum until reaching the airport. The airplane lost the voltage regulator again yesterday on the flight right after mine, and so it is down for mx. They are "trying to pinpoint the problem," but it concerns me that this keeps happening. It's as if it is almost on a timer to go out. Plese give me some feedback and tell me what you guys would feel in my shoes. Thanks a lot!
-eriknorth

 

[eriknorth]

I know that you can fly without electrical in the event that it happens, but is this something that I should be concerned about?

 

[mar]

Black magic and voodoo

As far as I'm concerned, whenever we switch on the master switch it's all black magic and voodoo.

I would probably avoid that airplane for night and/or instrument flights until they get it straightened out.

Try to be patient with the mx guys. Who knows what's going on? They may finally rewire the whole stinkin' plane. But stay involved like you are. Most mechanics like to teach pilots a little something about systems--you may actually learn something useful.

I've had a few electrical failures in single-engine machines. It keeps you on your toes but it's mostly a big inconvenience.

Best wishes.

 

[bobbysamd]

Maintenance

Take a look at the airplane's logbooks. Are the mechanics signing off the airplane and returning it to the line every time? Something's definitely amiss.

I don't think that I'd fly the airplane. It is not airworthy if a known system is inop or intermittent.

I definitely would not fly it at night or on instruments until the problem is straightened out once and for all. In the meantime, review your light gun signals and take a flashlight.

Good luck with your flying.

 

[flydog]

I owned a C-150 once where the voltage regulator had to be replaced. The mechanic wired the new unit backwards which caused and increase in charging proportionate to engine RPM. During a normal runup the ammeter checked out ok however soon after takeoff it pegged out and stayed there. Even though I pulled back the power to cruise fairly quickly after I detected the problem it was too late. The wiring began to smoke and catch fire. Most of the systems including the flaps, radios, etc failed within a few minutes as I returned to the airport.

The total damage to the airplane was in excess of $8,000 (by the way I paid $13,500 for the airplane 3 months prior). Most of the electrical system had to be replaced including a flap motor, all the radios, wiring, etc. I believe the only items that survived where the exterior lights and one flap motor. The radios were so fried they could not even be overhauled. The mechanic refused to pay for the repairs and I got stuck for the bill. The same mechanic also overhauled an engine on a Cherokee that on its way back to home base suffered a complete engine failure and crashed.

Be wary of whomever is working on your airplane. A problem as simple as reversing two wires can be fatal and difficult to spot on a preflight. Make sure you do a full power runup for at least 30 seconds before your first fligth after maintenance.

As far as your problem the electrical system on these airplanes is fairly simple. If the alternator and voltage regulator are replaced and the problem persists then there is a momentary short somewhere in the airplane that is causing the discharge.

 

[eriknorth]

Thanks for the replies. I'll definately heed all the advice and do a little investigating for myself. Unfortunately, the flight school I fly from only has two planes right now, the other being a 152, and those are a little small for me (I'm 6'5"). Some might say I should change flight schools, but I couldn't possibly be happier with my instuctor right now, and I'd rather him instruct me in a plane that we have to wait a while to get back on the line than go to a bigger school where I'm just another student. This guy really cares about me becoming a good pilot, so he goes the extra mile to really teach me things and doesn't skimp out on anything. Let's just hope we have a competent mechanic. Thanks again!

 

[El Cid Av8or]

I wonder if they have checked the ground connections for corrosion too?