i decided to go out for a few landings today at KJYO (leesburg). it was pretty hot but i wanted the practice. during the preflight i discovered that the stall warning horn didn't work (used the inhale test on the wing opening) which i'd never seen happen before. since i was just going to do pattern work i decided to continue (i would not have done that if i was leaving the pattern). while taxiing the run-up area i noticed that the gps had powered itself off so i turned it back on thinking that might have toggled it myself. at the run-up i noticed that the gps was off again so something was wrong with it. once again, since i was just going to do pattern work i continued with the run-up procedures. when i did the run-up i then noticed that the EGT (exhaust gas temperature) needle pegged itself (which i had never seen happen before). i pondered that a bit and pulled the throttle out to idle. after a few seconds the needle dropped back to normal. i did the run-up again and, once again, the needle pegged itself. i kept checking the oil temperature and pressure gauges and they appeared pretty much normal. after a few tries of run-up and watching the needle i decided that 3 issues were enough so i called potomac (i had already gotten my ADIZ transponder code) and told them i was delaying takeoff due to an issue. i taxied back to the ramp and put the chocks and went to ask if i should really abort. a maint guy said that the EGT reading was probably not an issue but the stall horn was. i went back and tied down and called potomac to cancel (was a ADIZ flight plan).
i am continually uncertain about the EGT in terms of leaning and general indications. some percentage of the times that i fly the EGT seems to not be a reliable indication of engine temperature. i suppose that the oil temperature gauge is the best thing to check. i'm still pretty cautious about gauge issues. i definitely don't feel like i'm at a point where i can ignore unusual things that i haven't seen before. i'm probably being overcautious so it's time for some more reading i think.
2 comments:
I know its tempting to be concerned about being "too cautious", but honestly, I am not sure that is a bad thing when it comes to aircraft maintenance. Unfortunately, the NTSB's files are full of the stories of people who decided that a few small problems were no big deal, only to find results that were often disastrous.
For me, three relatively minor things is about the point when I consider it enough to call it quits as well.
Anyway, thanks for the nice story. Its always interesting and insightful to hear about the unusual things that happen in flying, and how we respond to them.
I also use the strike three method to determine when to call off a flight due to minor issues. I wonder if this mentality stems at all from the three strikes in baseball-- or if the three strikes comes from this mentality!
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