Failed ignition modules

[Ed Cesnalis]

Yes John, I'm about to call.

 

I'm not even positive that I need them, if I don't I'll sell them to my best friend after the price goes up

[FlyingMonkey]

Does anybody know what percentage of these things end up failing?  My 2007 CTSW starts fine, but I'd hate to find out there is a problem after the price goes moon shot.

[Roger Lee]

There are over 50K engines. The failures are less than 1%. It isn't worth loosing sleep over. I can happen, but why worry if it doesn't happen.

[sandpiper]

I'm doing it mainly for the soft start rather than do a Bully Hawk.

 

I don't know if a failure is on the horizon for me, or not. The starts are beginning not to be as "crisp" as they used to be, at least in my imagination. Kinda like the "auto rough" feature when you fly over water. That feature was standard equipment on every plane I have had.

[FastEddieB]

The failures are less than 1%.

Sure seems higher than that for certain years.

 

Is your data from ROTAX?

[chanik]

1%? Ultimately about 100% of these modules will fail. Their start circuit is based around an RC delay using an electrolytic capacitor and all such caps, like batteries, have limited lifespans which are greatly shortened by heat http://www.mouser.com/pdfdocs/ELNAReliabilityAlumElecCaps.pdfmainly due to gradual loss of electrolyte.

Good commercial caps are over 10,000hrs, like the Kemet one I suggest for battery backup but cheapo ones are often rated as low as 1000hrs at 105C which coincidentally is about when these modules can be counted on to fail.

[FlyingMonkey]

1%? Ultimately about 100% of these modules will fail. Their start circuit is based around an RC delay using an electrolytic capacitor and all such caps, like batteries, have limited lifespans which are greatly shortened by heat http://www.mouser.com/pdfdocs/ELNAReliabilityAlumElecCaps.pdfmainly due to gradual loss of electrolyte.

Good commercial caps are over 10,000hrs, like the Kemet one I suggest for battery backup but cheapo ones are often rated as low as 1000hrs at 105C which coincidentally is about when these modules can be counted on to fail.

 

We can probably stipulate that any man-made *anything* has a finite life span.  

 

My real question is:  How many of these modules will fail within, say, a normal 2000hr+ engine life cycle between rebuild/replacement?  It sounds like you'd expect the mean to be ~1000hrs, so by 1000hrs you'd expect about 50% of them to have failed...correct?

[Roger Lee]

Many modules have been on their engine since 1990 when the engine first came on the market.

[FlyingMonkey]

Many modules have been on their engine since 1990 when the engine first came on the market.

 

But are the failures for all modules, or mainly contained to a "bad batch" subset?

[Ed Cesnalis]

But are the failures for all modules, or mainly contained to a "bad batch" subset?

 

Read what Kurt wrote again, its all of them.  Not so much a matter of time but a matter of time at operating temps

[Marco01]

A Rotax french distributor just announced this week that they have found a solution, and are able to repair both modules for 420 $, with an average lead time of 3 weeks: I will probably use this solution:

 

Le motoriste lorrain propose de réparer les boîtiers d'allumage Ducati montés d'origine sur les Rotax 912 et 912 S. Une panne récurrente a été identifiée, concernant ces boîtiers. Après quelques années d'utilisation, certains refusent de déclencher les impulsions des bobines HT lors de la procédure de démarrage. Si une seule bobine en est affectée (et que l'autre est opérationnelle et sélectionnée), l'utilisateur ne s'en rend pas compte lors des tests ''magnéto'', car le boîtier se remet à fonctionner après la mise en route et ne pose plus de problème pendant la durée du vol. S'agissant d'une panne aléatoire, le boîtier défectueux peut se remettre à fonctionner normalement, puis lâcher de nouveau... Jusque là, pas de problème, ce n'est pas dangereux, car ne risquant pas d'occasionner un arrêt moteur en vol. En revanche, si les deux boîtiers présentent ce dysfonctionnement, le moteur ne peut plus démarrer et l'aéronef est cloué au sol jusqu'au remplacement de ces éléments. Loravia répare donc les boîtiers Ducati pour un tarif de 372 euros ttc, réparation assortie d'une garantie de 2 ans. Par ailleurs, Loravia rachète les boitiers défectueux (dans la mesure où ils sont réparables) au pris de 150 euros pièce.

 

Contact : Loravia - 57970 Aérodrome de Thionville - 03 82 56 63 71 - loravia@wanadoo.fr - http://www.loravia.com

[chanik]

But the Temp thing is a huge factor. It follows the arrhenius equation which boils down to: every 10C less temperature doubles life. So in a cool climate and if you happen to have good airflow over the top of your engine (airflow and engine temps seem to vary quite a bit from CT to CT) then you could get to 4000hrs. I got to 850hrs and the other pair that failed here at RHV failed at ~1000hrs. There is also a Remos here at the field with starting issues with close to 1800hrs about to get new modules. (Victory Aero does all the LSA work at RHV)

[IrishAl]

A BRIEF TRANSLATION OF THE FRENCH POST ABOVE - (DON'T TAKE IT FOR GOSPEL!)

 

A company called Lorrain (Loravia?) offers a repair service for the Ducati ignition modules mounted on the Rotax 912 and 912 S. A recurrent failure has been identified in them - after a few years of use, some refuse to trigger the pulses from the HT coils during the start up procedure. If only one coil is affected (and the other is operational and selected), the user may not realize there's a problem because after startup each coil functions normally during the flight.

 

With regard to a failed coil, the faulty unit can be fixed so that it operates normally, then you don't have to buy a new one...

 

So far, they have not caused a problem, and repairing them in this way is not dangerous because it is not likely to cause an engine failure during flight. 

 

if both modules suffer from this problem the engine will no longer start and the aircraft is grounded until you fit new modules.

 

Loravia can repair the Ducati ignition module for 372 euros ttc  (ttc - all-in price?) with a 2 year warranty. In addition,

Loravia will buy your old faulty ignition modules for 150 euros as long as they suffer from the standard starting issue (i.e are repairable.)

 

Contact : Loravia - 57970 Aérodrome de Thionville - 03 82 56 63 71 - loravia@wanadoo.fr - http://www.loravia.com 

[FastEddieB]

Every installation will be different, but when I installed my BullyHawk SoftStart module, part of the install was to apply these strips:

 

 

Does not look like mine got very toasty, and they failed after just under 400 hrs. and seven years.

[chanik]

So it isn't the only failure mode, Another possibility is that they washed their boards with a halogenated solvent like Trichlorethane. Which gradually destroys the aluminum. It's all conjecture, but that mode is the one that would explain cooling as a common fix. Eroding aluminum leads to high leakage current through the cap which is greatly reduced with lower temperature. resistors, chips and transistors, etc will not care about 40C -> 10C temp shift.

[Tom Baker]

Kurt, do you think this could also be related to the switch to lead free solder in the EU? Someone had floated that idea a while back.

[chanik]

Kurt, do you think this could also be related to the switch to lead free solder in the EU? Someone had floated that idea a while back.

Nope. Pb free often creates intermittent contacts as the solder is harder to wet and easier to crack; however it tends to manifest as infant mortality and not after some hundred of operating hours. And while you can often find a bad connection via thermal contraction using freeze-spray on a board, you would never expect that to be repeatable across many boards and with such a small shift in temperature

[IrishAl]

Nope. Pb free ............ tends to manifest as infant mortality and not after some hundred of operating hours.

 

Kurt, it seems that empirical evidence suggests otherwise.  

 

My kids have burned out several games consoles all due to the 'red ring of death', caused by cracking leadfree solder.  There are many thousands of examples of this type of failure and it's always heat related and it happens only after hundreds of hours of usage........

[Marco01]

Based on my electronic background,I would vote for one capacitor failure: those kind of components always have their electrical properties influenced by temperature and time. 

[FlyingMonkey]

Kurt, it seems that empirical evidence suggests otherwise.  

 

My kids have burned out several games consoles all due to the 'red ring of death', caused by cracking leadfree solder.  There are many thousands of examples of this type of failure and it's always heat related and it happens only after hundreds of hours of usage........

 

I think if you compare the vibratory environment of a game console to an aircraft engine bay you might find both what you and Kurt say make perfect sense and are not at all contradictory.

[IrishAl]

Andy - this is the part I was questioning:

 

 however it tends to manifest as infant mortality and not after some hundred of operating hours. 

[FlyingMonkey]

Andy - this is the part I was questioning:

 

Yeah, I understood.  But vibration is death to soldered connections, and there is a whole lot more of it in an airplane than a console, causing quicker failure.  IMO, of course.

[Roger Lee]

"But are the failures for all modules, or mainly contained to a "bad batch" subset?

 

Ed quote:

Read what Kurt wrote again, its all of them.  Not so much a matter of time but a matter of time at operating temps."

 

 

 

It isn't all of them and never has been. I have friends with 3K-4K hours on their planes and have never had a failure. If there was a 100% failure rate regardless of time Rotax would have made major changes. Nobody keeps aviation parts in service with a 100% failure rate. If this were the case then I would be replacing these all the time with the 30+ aircraft I see a year.

 

The number one cause for Rotax engine issues are the owners. 

[Jacques]

The number one cause for Rotax engine issues are the owners.

 

  

[gbigs]

 

The number one cause for Rotax engine issues are the owners. 

 

Odd, the voltage regulator replacement is a Rotax originated issue.  The EGT sensor that went bad in my 912i was also a Rotax issue.  And the Sport Upgrade, though not a break-down is also something Rotax dreamed up. 

 

I was asked why I bought the aircraft new and why I want to buy my next aircraft new.  I answered simply, if not for the warranty I would be paying double for the product so much work has been necessary post purchase - none of it the owners issue.