So I have been flying with a 3DR Pixhawk for 2 years or so now without a single hardware issue but how long can this continue to be considered as reliable?
I guess that's an almost impossible question to answer as it will be the subject of many external influences but assuming input voltages are within limits, is there any reason to consider swapping it out for a new one as I would rather do that than risk £2k or £3k worth of kit..
I would tend to agree with you.. :o)
I would say you got a pixhawk from a great batch!
Thanks everybody, long live Pixhawk! :o)
I've been flying with old 8 bit APM 2.5 controller for many years now and subjected to humid and wet condition flight. So far no problem. All my planes survived solo autonomous flight. Not going to go for Pixhawk yet. Not going to fix anything that is not broken. You just need to trust your build.
MTBF characteristics vary a lot regarding the type of device you are talking about.
Generally pure electronic devices have a very noticeable spike in failure rate initially, but that falls of rapidly to a very low failure expectancy which rises slowly over time.
So basically with pure electronic devices, if you get one that has survived an initial break in period, you are actually much better of than with a brand new one.
It is however at that point you need to take a look at the true long term MTBF and for something like this possibly replace it at about half way there.
No matter what you do, especially with something as complicated as a flight controller, it is always a crap shoot, a balance between the initial failure period and your gamble of when it is going to finally fail.
Forthunately our modern flight controllers, generally use reliable devices and assuming something external does not cause a failure, tend to last a long time.
In continuous commercial use you might want to think about replacing a Pixhawk or equivalent in 3 or 4 years, but even then to make it worth while you would need a burn in program for the replacement that insured you were beyond the initial failure period.
And as the other people said, most of the other components are actually more likely to fail than the flight controller:
Batteries fail a lot, ESCs suffer from high power dissipation, servos are complex mechanically and generally use brushed motors with teeny tiny brushes and even frames have problems with stress and fasteners loosening up.
The failure rate for electronics is high is high at first, then goes down and then goes up again in time.
So, if the flight controller has not failed in the first few months of use you shouldn't have anything to worry about for many years to come.
Thanks all, that's all very positive..
Here it is in action, will retain it: https://youtu.be/_iBh1XrxJXc
I've been experimenting with folding props but have now concluded that they are inherently more prone to vibrations so have reverted to one piece props with quick release adapters which actually work really and make it much more convenient for transportation and storage.
Skip to 4:30 for rock steady loiter..
Not to mention the servos, they can just stop working all of a sudden. With APM I will still able to fly without issues without rudder and with only one aileron, but the elevator would be catastrophic.
Regarding electronics, normally it doesn't 'wear' if used within specs, except the eeprom memories, which will support a certain number of write cycles before wearing off. Usually it's a huge number which is not expected to be reached for APM.
For example have a look at : http://hackaday.com/2011/05/16/destroying-an-arduinos-eeprom/
+1. I have an APM 2.0 flying for four years with no issues but I change two times failed servos (fortunetly discover fail on ground :) ) , perhaps you can think in that components first as Paul recommends, check motor bearings too or change them.
You could swap it out for a new one that might fail on its first flight.
As long as everything is kept within spec there is no reason why good quality electronics should not last for years, my Hi-Fi gear is all from the 80's and still working and sounding well.
I suspect other items might fail before you flight controller, Motors, Batteries, ESC,s Radio Gear are all more susceptible to early failures than a flight controller.