Thanks for posting that story, Capitaine. Sad to hear of those problems, as well as yet another crap story about Calvi (these are found all over the aviation internet, not just on EuroGA). I had something very similar in 2005 at San Sebastian and eventually, magically, the blocked plug cleared, but ever since then I carry a big toolkit, enough to do a complete 50hr service – about 15kg.
Just read the shutdown thread – I’m well and truly down the rabbit hole, a bit like first discovering wikipedia.
Hopefully leaning after landing is the answer to keeping the plugs clean then. Carrying a toolkit is a good idea, but I’d have to learn what to do with it first – joking aside, I must learn enough to get myself out of trouble. The early Aéropostale pilots spent a year or two as mechanics before flying, so they could make proper repairs themselves after crashing in the desert
Thanks A_and_C, just found and read it. Everything makes sense, but not sure I agree with running up to 1800rpm before shutdown (but not sufficiently qualified to argue about it).
The biggest fleet that uses the Lycoming shut down as in the SI above is the RAF Grob 115 fleet that at its peak was about 120 aircraft, as you might understand this policy is enforced with military discipline so it is safe to say it happens on each shutdown.
I am in a position to know the engine overhaul company that is contracted to the RAF to overhaul these engines and the general opinion is there is no evidence whatsoever that the practice damages the engines as the vast majority reach TBO.
I don’t think anyone suggests the 1800rpm bit does any harm; the Q is whether there is any point in doing it.
One advantage I have heard is a cleaner shutdown (less shaking) and maybe less fuel left in the fuel pipes going to the engine which is safer especially if you are going to be starting again soon.
I did 7 flights today with 5 of those being almost immediate restarts, the 1800rpm procedure being done on each one, and we had 6 aircraft doing the same. Not one had an issue with a hot start.
That sounds like a very good data point for doing the 1800 rpm bit.
OTOH I have seen a lot of people struggle with hot starts, and IIRC none of them was following the POH procedure (instead using something they got from some type specific forum) which for me has always worked for the 16 years I’ve had the plane.
The biggest factor with the good hot re-start on the Grob 115 is that it is fitted with a slickstart.
Peter
I did have two C152’s ( working next door to Balliol I guess ) and we had plug fowling problems at about 25-30 from the last check, introduction of the Lycoming 1800 rpm shutdown completely stopped these problems with the plugs making it to the 50 hour check without fowling.
The other addition to standard to increase reliability was fitting slickstarts to the fleet, engines fired up instantly even with the most ham fisted student, after fitting the slickstart I never changed a starter motor and battery life extended. I would guess that the slickstart paid for its self inside 300 hours due to maintenance savings .
What’s a Slickstart?
Thanks Capitaine,
I am sure I must have come across this SB years ago but we never really absorbed it by the looks of it. The 1800RPM procedure sounds like a good idea, will introduce it to see if we get better results with it.
With consequent leaning whenever the engine is running we managed to get fouling almost totally stopped, but the 1800 RPM procedure appears to be an additional step to assure no more fouling.
I hope we will get UL91 soon everywhere, that is even more effective of course….
