David Megginson <[EMAIL PROTECTED]> writes: > [EMAIL PROTECTED] writes: > > > And having experienced exactly this in a real airplane, in > > instrument conditions, I can tell that what you're seeing is quite > > realistic. > > A full narrative would be very welcome, if it's not too emotionally > difficult.
Hmmm... Fortunately, there's not a lot to tell. I was on an instrument proficiency check, because I hadn't done any instrument flying in the previous six months. We were mostly in the clouds although we'd occasionally see ground below us. What I noticed in this case was an inconsistency between the DG and the AI. The AI said I was banking but the DG wasn't changing to indicate the turn I would expect in a bank. When I began to "correct" the bank with a little bit of aileron input, these two instruments also didn't behave as I would expect. A cross check of the turn coordinator indicated that it did not correspond with the AI. A glance at the vacuum gauge confirmed substantial loss of vacuum, i.e. it wasn't quite a complete failure, which was why the instruments appeared ok -- the AI didn't tumble or anything drastic like that -- but rather they spun down slowly, becoming more and more unreliable. I transitioned to using the magnetic compass and the turn coordinator as my primary instruments, requested a descent to below the clouds, and flew home in VFR conditions. We're all trained, during instrument training, to do a complete instrument scan. The way I was trained was to use the standard "T" instruments [1] in my primary scan, and expand to the rest of the panel every 30 seconds or so. If anything looked "funny" or didn't correspond, then crosscheck right away. I had no way of knowing how quickly I would catch a vacuum failure. It was really nice to find that I did, in fact, notice that things were awry, and transitioned to the alternate instruments properly and quickly. Doing instrument proficiency practice in a simulator (whether during initial instrument training or post rating) would do loads of good for any pilot, to reinforce the need to (and force the practice of) crosschecking the instruments. Having realistic instrument behavior in FG and adding an "instructor" station with the ability to create failures will be really nice. Cheers, Derrell [1] The standard "T" instruments on the panel are the top 3 directly in front of you (airspeed, AI, altimeter), and the middle instrument of the bottom 3 (DG). _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
