Alternator Failure?

[Rick]

Flew up to Manassas this morning to visit my daughter. Fired up the plane to return home this afternoon and had the alternator failure alarm. All CBs ok, reset the alternator (twice) but no change. The AMPS was stuck at zero, and voltage dropping slowly. Applying a load (pitot heat and the lights) showed more voltage drop, still no charge. Rental car and 4 hours later, I'm now home, but the plane will be have to be checked out by the local shop up there tomorrow.

My question - there was some talk in aonther thread about losing the sensor and/or a wire on the alternator causing the alternator alarm. To me, it sure feels like a true alternator failure. Any advice I can give those guys up there to help them out? Also, assuming it is the alternator, is Diamond the only source, or is it just some "standard" aviation alternator? There is no Diamond shop at this airport.

Thanks,
Rick

[Steve]

Have them check the alternator ground wire. Has a history of vibration cracks on the ring terminal. Mine failed during the runup for my annual (lucky). See photo below for how I tried to reinforce it with a strain relief. If it truly is a bad alternator, I believe that Plane Power has a PMA replacement for the Diamond Star. Supposedly more reliable and a couple of pounds lighter, plus cheaper.

http://www.plane-power.com/TAL24-70.htm

Good luck.

Steve

[Rick]

Thanks, Steve. It looks like it IS the alternator, according to the shop. All wires were solidly connected, so he pulled the alternator and says it's not producing anything. In an effort to move things along, I just ordered a Plane-Power AL24-70 kit, which is PMA'ed for the DA40, to be delivered tomorrow. This guy says he's installed several PP alternators before (but not in a DA40) and had good luck, so I guess I'll give one a try and see what happens.

[Rick]

Flew home today with a new Plane-Power alternator installed. The old alternator is now in a box in my garage - one of the brushes was completely worn away, which is why it failed. It was exactly 5 years old with 1400 hours on it. I may have it rebuilt as a spare in case I (or some other DAN member) need it one day...

I went back over the data files from the trip before the failure, and there were no indications of an alternator problem - voltage was rock-solid at 28.4 all flight.

[BlackMammoth]

Our alternator gave a quick voltage drop (momentary illuminated voltage light) about 1 hour before it failed... then it was DEAD. Luckily it wasn't a difficult part to replace from local distribution.

[Rick]

Our alternator gave a quick voltage drop (momentary illuminated voltage light) about 1 hour before it failed... then it was DEAD. Luckily it wasn't a difficult part to replace from local distribution.

Phil, how old was yours when it failed, and how many hours?

[BlackMammoth]

2003 aircraft, it failed in 2008. I believe this would have been around 540 hours - still looking for log entry

[Gary]

How much do the different alternator options cost? I assume that they are relatively easy to change out as long as the belt is still good. We need to add a section in the wiki where we post the time to failure for various components by brand.

[Tommy]

Try one of these. They are relatively inexpensive given the peace of mind they provide.
http://www.flypas.com/images/powerplusflierfinal.pdf

[Rick]

How much do the different alternator options cost? I assume that they are relatively easy to change out as long as the belt is still good. We need to add a section in the wiki where we post the time to failure for various components by brand.

The AL24-70 cost me $542 from AircraftSpruce, and it came with all the brackets and mounting hardware. It is also 2.5 lbs lighter than the Kelly OEM alternator. The shop quoted me just under a grand for a new stock alternator from their source.

I think a WIKI section for failure times is a great idea - so far our 2 samples make it sound like 5 years would be a good point to check the alternator! Although I know of both an '04 and '05 DA40 still on the original alternators...

Try one of these. They are relatively inexpensive given the peace of mind they provide.
http://www.flypas.com/images/powerplusflierfinal.pdf

I was wishing I had one of these - it would have at least allowed me to bring the plane home Sunday (I think, although maybe not the intent of a "backup" alternator). I wonder if there are any other DA40 options for a second alternator besides this one? It seems like a good idea for any glass-panel airplane. I think Cirri have dual alternators as standard equipment...