PMag Reliability

[DanH]

Originally Posted by Bob Martin

.....don't we install blast tubes to the mags as well....and the alternator and the engine driven fuel pump???

Obviously all the reasons have to do with temperature. In the case of mags, alternators and fuel pumps, can anyone here tell us a measured before (without blast tube) and after (with blast tube) temperature for any of them?

While contemplating that bit of thread drift, let's return to Paul's question. He needs data to convince UK authorities of P-mag reliability.

I contend blast tubes don't actually lower component temperature all that much, so I consider the P-mag requirement for a blast tube to be an indication that the electronics are temperature-marginal. I ask for actual measured temperatures, with which anyone is quite welcome to prove me wrong. Heck, I'd be happy to be wrong.

[frankh]

There is a guy that had a forced landing.. Now was it forced or was it precautionary I can't remember. But he did document the event here on VAF.

The early failure mode is one of the Pmags would lose its timing and the cyl head and oil temps would rapidly go out of control dure to pre-igniton.

Now IF you shut down the offending Pmag normal service is restored, but thats a big "IF".

The guy I'm tolking about either chose to or was forced to land on a road.

Now this was a few years back, the modern generation I don't believe have had any problems.

Frank

[paul330]

I know that PMags suffered early in their development, mainly due to overheating. I also believe that later upgrades and the use of blast tubes seem to have eliminated this failure mode. I also know that Pmags will fail from time to time just as traditional mags will. Hard statistics are going to be difficult to lay my hands on but my gut feeling is that the mature PMag has to be more reliable than the magneto.

Most importantly, I need to be able to tell the LAA that in the last 4 years or so, there has been no dual failure. I believe that to be the case as I am sure I would have heard on this forum. Of course, it is difficult to prove a negative but at least I can say I have researched the matter and found no case.

Thanks for your interest and help.

[Ted Johns]

I know that PMags suffered early in their development, mainly due to overheating.

Pmags suffered from more than temperature issues, most of which were commented on in this forum. Do some searching.

I remember issues with internal magnet and/or sensor mounting coming loose. There was a big stink about the mechanical design of the magnet (or sensor) mounting at one point. I remember issues with SW crashes (causing timing maladies) that were probably caused by temperature. I remember issues with the "blow in the tube" timing setting being lost.

All these issues seem to have finally been addressed competently.

But if you want hard statistics, you have two sources. NTSB and Emagair themselves. Of those two, probably only Emagair could tell you how many have failed vs how many have been sold over the last x years. I don't think that how many units they have produced is required to be public knowledge.

Best Luck.

[frankh]

Actual double failures?..Probably none..But if you loose the timing one (and don't shtdown the offending Pmag) it could and we think did cause a forced landing.

Now of course now that anyone who flys 2 Pmags will be much more alert and ready to try shutting down one of them to isolate the fault.

I am quite comfortable flying a Pmag and Emag combo.

Frank

[cujet]

260 hours on my new style P-Mag, no issues what so ever.

[rv8or]

We had an Emag failure that upset the timing and the engine only just ran, did not keep us in the air. Luckily we were over an airport and put it down.
It is extremely important that if you are running Pmags or Emags that you have to be aware of this issue so if presented with a very rough engine to try switching of one Pmag at a time. This should be part of the emergency checks if running Pmags. It is for us now.
We were not aware of the failure mode until it happened and it was only on the ground that we thought about it.

Rob

[John Collier]

I installed an EIC, so I can monitor the timing and harness. It will alert you if the timing is off more than six degrees. On the ground, you can also check the prop position for each PMag, therefore allowing you to check the index without removing the cowling. Maybe having a monitor would help your certification.

[N941WR]

Back to the question.

The problem is there is not a P-mag for a six cylinder engine just yet.

Emag has their six cylinder ignition in testing but it is anyone's guess as to when they are going to release it.

The architecture of the six cylinder ignition is significantly different than the 113 and 114?s. Thus, our experience with the current units does not translate to the RV-10.

[N941WR]

Originally Posted by rv8or

We had an Emag failure that upset the timing and the engine only just ran, did not keep us in the air. Luckily we were over an airport and put it down.
It is extremely important that if you are running Pmags or Emags that you have to be aware of this issue so if presented with a very rough engine to try switching of one Pmag at a time. This should be part of the emergency checks if running Pmags. It is for us now.
We were not aware of the failure mode until it happened and it was only on the ground that we thought about it.

Rob

Rob is correct. If you are flying and experience a suspected ignition issue, turn one ignition off and if the engine runs rough, turn it off immediately and turn on the other ignition.

You have a 50/50 chance of turning off the offending ignition. If you pick the bad ignition, the engine will settle down immediately. If you shut down the good ignition, it will run really really rough. In that case, turn off the ignition and turn back on the first ignition you turned off.

For those who haven't lived through the teething problems of the early P-mags, if you have the 113 series (they do not have cooling fins on the neck) and you don't know if they have been back for both the software and magnet upgrades, stop flying immediately!

The only fix is to send them back to Emag for the upgrades. We have had EICommander clients who continued to fly the 113's and knowingly ignored the service bulletins because the ignitions were working fine, right up until they didn't work fine. Good news for us because that pushed them to purchase and install an EICommander.