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Predictive maintenance for GA

I think the main problem is we have no data collection taking place, and rigging something up is really complicated.

The nearest you can get is engine monitoring, with the various products out there (EDM700 being the bottom end). AFAIK none have internet connectivity; you would need a SIM card, or wifi which connects in the hangar, or connects to your phone like the Golze ADL can do. These can detect some early signs of valve failure, but not all, and sticky valves are likely to show up only at startup, and there is no way to detect them running too hot (as a result of not sitting down fully) during flight.

The standard service regime, where you do a “50hr check” during which you eyeball as much as you can, works generally well enough.

And sensors tend to fail more often than the thing being monitored, unless you spend serious money, which doesn’t happen in GA which uses mainly 1970s Vauxhall Viva quality electrical parts

One thing which I wondered about is vibration spectrum monitoring. This is used on upmarket helicopters and apparently with good success. They also have chip detectors in their gearboxes; that might be a really good thing to have in our engines and not hard to make.

Administrator
Shoreham EGKA, United Kingdom

We’ve found the Savvy Analysis service very useful. Upload data from the JPI engine monitor periodically and this highlights any unusual issues, especially overheating, in any of the cylinders. Helps spot a faulty cylinder early which can then be borescoped before it gets worse. One advantage is that with so many aircraft uploading data, they can compare measurements across many aircraft of similar type, highlighting if yours is operating out of the normal envelope. There has been some useful advice provided. It’s also a good way to determine if GAMI injectors would be worthwhile and what the settings/size of those need to be.

We also take oil samples every 50 hour oil change and send them off for analysis. That (and opening up the oil filter) was what finally got us to determine when to overhaul the engine – we got a reasonably early warning that it was coming.

Without further sensors fitted, it would rely on pilot reports and record keeping about flight conditions etc. I could imagine that where an aircraft is shared between more pilots, or general club use, reports of hard landings etc would not always be forthcoming, especially when some would say that’s quite subjective to determine.

Perhaps a bit more information and tips about what owners can do to optimise maintenance costs would be useful – the adoption of Part ML for ELA2 from March 2020 hasn’t been well publicised, so when developing the new approved maintenance program (required before next ARC issued), the kinds of things that could sensibly be checked or replaced less frequently would be good to know. I suspect many pilots leave this entirely to their maintenance organisation who are of course primarily concerned with safety whereas the pilot might have slightly more interest in balancing the total cost. I mean no disrespect to the professionals who keep us airborne by saying that. Mike Busch’s book on aircraft ownership (while focussed on the US private owner) makes many good points in this respect and gives relevant examples.

The information doesn’t have to be for the most complex aspects. For example, I have been quite surprised to come across more than one owner who recorded hours until next service based on Hobbs rather than airborne flight hours.

So rather than having purely a computerised Cloud offering, I wonder if something similar to Savvy’s expert mediation service between owners and maintenance organisations might be of interest in Europe. There are some voluntary standard procedures which maintenance organisations can adhere to, such as AOPA code of practice, but an expert third party who can understand the issues and explain/mediate where unexpected high costs are involved could be very useful. I’m pleased to say we’ve never required that for our aircraft.

EGBJ, United Kingdom

You will have 3 main problems vs airlines:

  • Number of flights to get data from
  • Lack of sensors and data-logging devices
  • Lack of SOPs (human and electronic)
    All these compound to give poor statistics and a low signal-to-noise ratio, ie difficult to extract trends and achieve the preventive part.
ESMK, Sweden

Thank you everybody for the answers.

@DavidC I haven’t heard of SavvyAnalysis or SavvyAviation. Now that I have reviewed their SavvyAnalysis app I can say it looks a lot like what I wanted to build (huh!). As far as I know, they are the only ones who provide this type of analytics, and they even include it with their annual mx management package. As I understand, SavvyMx is not that popular in Europe, so there should be room for competition.

DavidC wrote:

I wonder if something similar to Savvy’s expert mediation service between owners and maintenance organisations might be of interest in Europe.
isn’t CAMO supposed to do a lot of what SavvyMx does?

I also see that maintenance papers are stored offline. Wouldn’t it be a good idea to have an online backup?

At our airline maintenance crew used AMOS for maintenance tracking. They provide an app where you can conveniently log everything you do. Then you can print out a report, if you need to. What if this approach is adopted in GA? Maintenance crews could use an app for logging, and the log would be stored in the cloud. Aircraft owners could log in and view all the maintenance records.

Now, what if we combine the predictive analytics and monitoring part with the digital mx part? We could have a service where aircraft owners share data with their mx crew, and visa versa. That way, we have a full digital footprint of an aircraft. Engine data would help mx crew with diagnostics, and maintenance logs would be in the cloud for the owner to access at any time. Should you decide to sell your plane or change a mx shop, your plane’s data is all gathered in one place and can be easily shared with anyone interested.

Russian Federation

soin08 wrote:

isn’t CAMO supposed to do a lot of what SavvyMx does?

If you have a CAMO that is independent of your repair shop, it is exactly like this – the reality is, however, that in Europe there are very few independent CAMOs.

Germany

The CAMO documents I’ve seen have been excel files mostly. An app would be nice.

CB IR Instruction
LOWG, LOWW

LeSving wrote:

The reason is that since there is no cost related to unreliability (other than grief), this will be the cheapest method, by far. What we want, is only to be reasonable sure that the aircraft will fly trouble free the next hour.

I don’t completely agree with this. One significant profile of GA’s utility is going to places you could never go to, in the available time (e.g. a weekend). If you are stuck on Sunday in the very nice place you spent the weekend / week at, but it doesn’t have good CAT links (a very typical case), because your GA plane was unreliable and cannot bring you back, you are in trouble. Your Monday appointments are toast; you are missed at work. Going home by rail / rented car can easily take a day or two.

People using GA for travel, rather than only for “bimbling”, would, I think, gladly increase their costs by say 10%, in exchange for getting a factor of 10 reduction in such “unreliability”.

ELLX

I agree. That is why I maintain my plane on a “fix everything immediately” basis. Downtime is a big hassle and corrosive to one’s interest in using the plane.

Actually deferring maintenance doesn’t save money. You still have to do it. The only time it’s “worth doing” is if you are selling the plane and hoping to find a buyer who didn’t get a good prebuy done

Administrator
Shoreham EGKA, United Kingdom

soin08 wrote:

As I understand, SavvyMx is not that popular in Europe, so there should be room for competition

It’s not only that: Savvy (and Mike Busch in general) have a Philosophy that is kind of the exact opposite of preventive maintenance. They have a very strict “If it’s not (yet) broken don’t fix it” policy.
Therefore they do the very same kind of Analysis one would need for preventive maintenance but apply it “only” for detecting broken things a s rapidly as possible rather than detecting things that could brake soon and therefore need to be fixed preventively…

Therefore there might be even more room for competition – if (and only if) the financial value of preventive maintenance in GA can be demonstrated…

Germany

They have a very strict “If it’s not (yet) broken don’t fix it” policy.

In reality, that policy – depending on details – is justified for the machinery we operate.

Obviously one cannot take it to the extreme e.g. not inspect the control linkages until the aileron falls off But the Annual inspection deals with that.

On the engine, provided it is run regularly, and not grossly mismanaged thermally, there isn’t much you can do differently which will make it last longer. As far as anyone can tell it doesn’t even matter which oil you use, whether it will make say TBO plus 50%.

Administrator
Shoreham EGKA, United Kingdom
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