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Preventative Maintenance - A networking idea

Discussion in 'General Discussion' started by Tq2Jetman, Mar 22, 2016.

  1. Yes and if it was in place I would use it.

    0 vote(s)
  2. Not interested at all - waste of time

  3. Yes - but its something DJI should run with.

Multiple votes are allowed.
  1. Tq2Jetman

    Mar 6, 2016
    Likes Received:
    Beechboro, WA
    I am relatively new (about 9 months) into Remotely Piloted Aircraft (RPA) but I have been around aircraft in maintenance related matters since 1965 (Yes 51 years). I live in Perth, Western Australia. Purchased my Inspire 1 Pro a few weeks ago now. Had P3 since July 2015. The thought of losing either with no warning is a major concern even though both are well insured.

    The basic question I would like to get my head inside is "Is it possible to better define how to mitigate the risk of crashing by some type of preventative maintenance program?".

    Aside from the bleeding obvious - flying into trees, houses, power lines etc what are the key risks for the Inspire 1 RPA?

    a) Engine failure
    b) ESC failure
    c) Propeller failure

    Can we mitigate the risk for these?

    In a normal aircraft one relies heavily on the various equipment manufacturers for such key data as "Mean Time Between Failures (MTBF)" and "Recommended Lives". But as stated in several other areas, for electrical components this can be a tad tricky.

    Now to date I have been singularly unsuccessful in engaging DJI techs on such mundane things as MTBF's. If anyone might have a clue, based on sales of spares and reported crashes I would have thought DJI would.

    So be it. Is there another solution to tracking/collecting these failures? Well I think there is. If suppliers and users could easily contribute to one data collection source perhaps over time some meaningful stats could be seen. Data needs to be tabulated so that it is good and easy to understand reports can be used. Is this forum the place for such a feature or would any readers feel interested in such a database if one were available?

    In the short term I plan to commence the following data collection on both my RPA's.

    a) Engine/ESC condition:
    i) Within 1 min of last flight, measure and record each engines temp using an infrared thermometer. This is in addition to checking by hand for temp and ease of turning.
    ii) Every routine inspection check engine rpm again using an infrared rpm gauge.

    Q. At what temp and/or rpm should the engine and/or ESC be replaced. To leave it "On Condition" is just asking for serious trouble at some future point.

    b) Propeller condition (Regardless of type):
    i) At each removal check with extreme care for any cracks or other defects, including the attachment mechanism. Paying particular attention to the hubs and leading edges. If in doubt - chuck it out. Cheap option compared to a failure.

    In both cases record the event in the RPAs maintenance log.
  2. Kilrah

    Feb 3, 2015
    Likes Received:
    But the full scale equipment manufacturers are obligated to do the required large scale and real-time testing to determine those - no such thing in the hobby or UAS market yet so basically you build a thing and send it out with no idea of its long term reliability. They simply have no clue.And given there are no SN's for parts they won't be tracking anything or building a database from returns/repairs.

    IMO without a centralized database (DJI) you won't get a meaningful sample size.

    That's good

    That's useless. RPM is regulated so you'll always measure the same. The ESCs would need to measure and provide their regulation parameters for us to be able to see the evolution (= see that the power required to reach a given RPM incresases), but they don't (or if they do we don't have access to that data). The closest thing now is temperature as above. And you can't really measure ESC temp (which is probably more important than the motor's) on the I1 given it's buried below the motor.
  3. The Editor

    The Editor Moderator
    Staff Member

    Aug 7, 2013
    Likes Received:
    I applaud your sentiment but as Kilrah states above, there is no regulatory mechanism in place and no way to trace parts via serial numbers (with the exception of a few)
    I fly commercially and have a maintenance regime that I follow as well as always checking my motor temperatures by hand after every flight and the free running of the motors. This helps identify early problems with the bearings which I replace at 100 hours or sooner if required.
    ESC's cannot be serviced and they either work......or they don't. Nearly every single esc fault is a FET failure and with the amount of current the arrays are switching it's no surprise that failures are sudden and non predictable.
    I have found that multirotors follow the bathtub curve as regards to failure rate and if you do not have any problems in the early life of the machine you will follow this curve and probably have a reliable aircraft.
    With a quad, inherently by design, if any one corner fails it's good night! It's just something we all live with but a comprehensive checklist before each flight together with sensible 'maintenance' regime helps mitigate any 'stupid' or preventable errors/failures.