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GPU Mishap


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Well, Father's Day Weekend got off to a hot smokey sizzle yesterday. Sadly, I wish i were talking about the weather.

I called ahead to our favorite FBO (Name shall be withheld) and asked for our M20K to be pulled out of her nest and have the tires and tanks topped off for the trip to New Orleans. We were getting an early start as the CumuloBoomers along the Gulf Coast were still in the smallish development phase of their day.

I pulled up to the ramp and found our bird out on the line with all services completed. We love this FBO. They are so efficient. Time to Load and preflight. With the cockpit flow going I turn on the master switch and NOTHING. Crap!!! No lights or sounds. The 8 month old Concorde was dead. Sooooo I called the FBO office and asked them the send the battery cart out with help. They do so.

The cart arrives with the fine gent who fueled us and did our tires. I would call him an experienced lineman and very competant. I get the battery box open and connect up the clamps. Then, before applying power, I recheck to make sure I have Red to Positive and Black to negative. They check out.

The line guy then plugs in his end of the cables into his battery cart, which is really built into their towing vehicle. The plan was to let the unit charge the battery up while I finished preflighting.

The line guy then says,"Why dont you turn on the master switch to make sure we are getting power". The brief sizzling sound combined with a puff of smoke from behind the panel still makes me sick to my stomach when I think of it.

Apparently, we got much more than the 12 volts that our 231 required. Or more amperage than the system can handle. The battery cart had multiple jacks to plug the cable into. And they were unmarked. The line guy has only worked there 2 months.

I am sure that their insurance will cover this. I have zero experience with this kind of FBO problem. But they are a VERY straight up operator from what I know of them. What I am worried about tho is that we  had 4 breakers popped and one of them was the autopilot. I had thought that this would be protected by the avionics master. 

Any thoughts on what other components are going to be fried?

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Well, Father's Day Weekend got off to a hot smokey sizzle yesterday. Sadly, I wish i were talking about the weather.
I called ahead to our favorite FBO (Name shall be withheld) and asked for our M20K to be pulled out of her nest and have the tires and tanks topped off for the trip to New Orleans. We were getting an early start as the CumuloBoomers along the Gulf Coast were still in the smallish development phase of their day.
I pulled up to the ramp and found our bird out on the line with all services completed. We love this FBO. They are so efficient. Time to Load and preflight. With the cockpit flow going I turn on the master switch and NOTHING. Crap!!! No lights or sounds. The 8 month old Concorde was dead. Sooooo I called the FBO office and asked them the send the battery cart out with help. They do so.
The cart arrives with the fine gent who fueled us and did our tires. I would call him an experienced lineman and very competant. I get the battery box open and connect up the clamps. Then, before applying power, I recheck to make sure I have Red to Positive and Black to negative. They check out.
The line guy then plugs in his end of the cables into his battery cart, which is really built into their towing vehicle. The plan was to let the unit charge the battery up while I finished preflighting.
The line guy then says,"Why dont you turn on the master switch to make sure we are getting power". The brief sizzling sound combined with a puff of smoke from behind the panel still makes me sick to my stomach when I think of it.
Apparently, we got much more than the 12 volts that our 231 required. Or more amperage than the system can handle. The battery cart had multiple jacks to plug the cable into. And they were unmarked. The line guy has only worked there 2 months.
I am sure that their insurance will cover this. I have zero experience with this kind of FBO problem. But they are a VERY straight up operator from what I know of them. What I am worried about tho is that we  had 4 breakers popped and one of them was the autopilot. I had thought that this would be protected by the avionics master. 
Any thoughts on what other components are going to be fried?


OMG! I would be sick too if that happened to me.

What exactly did they connect up to your plane? It sounds like he had you connected up to a 24/28V charging port.

With master on and the avionics master off, I would have thought only those items powered by the master should have been impacted. What were the 4 breakers that popped?



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I hate to hear stories like this this.  Bad for the owner, bad for the lineman, bad for the FBO and insurance has to spread the cost out ultimately affecting what we're charged to use the FBO.

I recently saw a plane damaged by a fuel truck.

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Curious, why would you consider jumping the plane and flying?

Especially if there is potential bad weather? I would pull the battery, charge it and make sure it holds a charge before I consider flying with a questionable battery.

I have had electrical failures in flight, and running on battery was not pleasant. I would not want to think how bad it could have been if my battery was questionable.

And lead acid batteries, when you drain them fully are often wrecked...

 

Tim

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Looks like 28 volts was applied instead of 14V. If you didn't turn on the avionics master the damage maybe limited to your battery, master relay, annunciator lights, engine instruments and anything connected to the main bus. On the GPU access little door I posted a decal indicating 14V. Most planes with GPUs access are 28V and later Mooneys are 28V also. You should always advice the lineman of the voltage required.

José

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I had the same thing happen in my 231, 12 volt.  New line kid, worked very hard to get the 28 V plug to fit.  When I came out there was water coming out of the bottom of the plane - and it was the middle of the winter.  That is the battery box drain, and the “water” was the battery boiling over.  The first problem is to clean the box, and it may need to be replaced.  It needs to be cleaned heavily with soda to neutralize and remove any acid, which will try to eat through the box, and if it succeeds with that, through the frame and skin of the aircraft.

Surprisingly, I had no aftereffects, and that was even after we flipped the Master on to get the JPI930 to come up and show us voltages and amperages, and why thyings weren’t working (that is when I figured out what the line guy had done).  The JPI is rated for 28 volts, so it was fine, and nothing else in the panel or the AP was hurt.  

There is a relay in the back of the aircraft near the charging plug, that fried, and prevented the plug in from working.  I found that quite awhile later when, on an Angel Flight, a guy with a jet picked up my passengers and needed priority or his jet would not start.  My engine got cold and after a few attempts to start, we needed to plug in.  Nothing.  So we had to fix that relay before I could leave.

I would not take off with that same battery after it has been cooked, but once the battery has been replaced and is new, if the charging system is working fine, I would not be concerned about taking off even if we needed some current help in cold weather.  As long as I know that what and the why, its fine.  If I have doubts about the equipment, that is another matter.

PS I don’t remember that we switched the Avionics Master on, just the aircraft Master which brings up the 930 automatically.  Don’t know what that would have done, but all of the avionics are 12 volts so would have been a problem I am sure.

Edited by jlunseth
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    FWIW, most newer avionics, and some older, are built to accept both 14v and 28v, but in wiring them up it is very rare that the power pins will take either voltage.  There is usually a pin for +14v and a separate pin for +28v.  For this reason I am not so sure that 28v applied to 14v/28v avionics will not cause severe damage.

 

Sorry to hear of this complication,

 

Ron

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Years ago, having some radio work done the shop pulled this same trick on my 12 volt F33A.  Blew the top off the battery.  Bent the cowling door and latches.  Battery box shaped like a beach ball (beech?).  Lied about what happened. All radios worked initially.  Over the next two years I think everything electrical needed repair.

Smoke and sound from behind the panel is sickening on the ground.  You need to have them check everything before flying.  Everything.  Anything that got the wrong voltage is suspect.  They check it and sign the logbook.  Do not fly away until this is done.

Tspear is correct, read his comment again.  I have had a jump start only once in 40 years.  That one time, the generator on my M20C quit as I leveled off at 9000.  In the dark.  That weak battery was dead as a doornail real soon.  Glad I had a flashlight. Fortunately, in the Mooney there was not enough room to kick myself in the rear.

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The times my battery was dead I either hand propped it (getting home) or scrubbed the flight.  I think I will continue that wise policy.  That said, I've kept my battery hooked up to a cheap motorcycle tender.  I've done that for two years with the Mooney, and for 7 with my old Cherokee.  I've yet to loose a battery doing it.  I hate scrubbing flights on nice days.

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