Tried to post last night and this morning, but the internet at the cheapie hotel (USD 100 per night...) I was staying did not actually work for more than for a few seconds at a time. Status update: During the last 1-2 hours of the flight yesterday I noticed some weird fluctuations of the oil temp - it kept on fluctuating between 140 and 170 degF (OAT 6 degC, FL140). I initially thought it was a loose connection, since oil pressure and everything else was steady as usual. So I wasnt bothered, and in any case I was too busy dodging build-ups etc. After clearing immigration/customs I had to start up again to re-position the aircraft to another apron, and then I noticed (a) the battery seemed a bit down and battled to crank the engine, and (b) the voltage when running at 1100-1200rpm was only 12.8V against normally 13.4-13.9V. I explained the issue to Jan Troskie a bit later, and he immediately zoomed in on the likely culprit: the alternator belt was worn and had started slipping when the engine got hot and needed tightening. So after breakfast this morning I went back to the airport, and with the assistance of one of the Air Seychelles ground handlers took the top and bottom cowling off (the top cowling is easy to undo for one person - the bottom one is nearly impossible to do alone but easy when you are two). Inspection showed that the alternator belt adjustment bolt (or whatever you call it - its the bolt that slides up and down a curved metal rail) already was at the max position. When we installed the EIS electronic ignition in December 2012, Jan put on a spare belt before re-installing the prop - and thanks for that, it saved the day. After a bit of fiddling, we had swapped the old for the new and tightened it so that it had a sideways play or around 5-7mm when pulling it hard by hand. The play with the old one was around 1.5 cm, and there were signs of glazing on the side. I cannot be sure if its correctly tightened, of course, but I will keep a close eye on the voltage tomorrow for any sign of fluctuation (= the new belt initially stretching). The normal procedure is to check the tension with a torque wrench on the pulley nut, or to use a belt tension meter - I have none of those, so have to use gut feel. Its also normal to check the tension again after 1 hour of operations - again not very practical for me since my flight to Pemba early tomorrow morning is 6-7 hours... BUT if there are signs of renewed slipping, I will switch to the backup alternator and run on that for a few hours. Then we can check and re-tighten when doing the next MPI at Wonderboom. If everything goes according to plan, I will stay overnight in Pemba and then fly to Polokwane (6 hours) for entry formalities on Monday - before continuing to Wonderboom for the MPI (and a beer, I guess...). Im still keen to participate in the PTAR, even if unforeseen events means I need to find a new navigator within the next few days (my normal navigator Mike Visagie is on an oil platform on its way to Angola, and last years navigator Axel Matamba is on stand-by for his final CPL/IF test...)
Posted on: Sat, 24 May 2014 08:56:21 +0000
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