VASI Approaches ( Part 1 ) Actually, only three of the approaches in front of you rely on the VASI; the other three use the PAPI. PAPI, the Precision Approach Path Indicator, as its name implies, vertically guides you to the runway with a narrower beam of light, thus more precisely Since the PAPI systems uses a narrower beam of light you must fly the glide path more precisely than the VASI to stay on the bea m. You really have to stay on your toes when flying the VASI because there is no indication that you are drifting off the glide path until the lights switch to red-red or white-white. You may find yourself flying an S-slope down to the runway: bump the white-white, descend and bump the red-red, climb and bump the white-white, etc. The PAPI, with its extra lights, forewarns you when you are drifting from the desired glide path. If you see three reds or three whites, slightly off the glide path, its time to take the necessary action to stop the drift. Minor power adjustments should do it and knowing the correct RPM for the desired rate of descent puts you a jump ahead of the game, where the lights are determined that you shant stay between them. Its actually rather fun. You feel as if youve beaten the system when you slide all the way down the glide path with the PAPI lights properly remaining white- white-red-red. The approaches that you will fly begin 4.0 NM before reaching the FAF. This provides a little over 3 minutes to Ident the localizer and to stabilize the aircraft in straight and level flight on the localizer heading. All speeds are 75 kts., with one notch of flaps dropped. The intercept altitudes shown are taken from the approach plates for an ILS approach to the same runway. They are your expected altitudes as you cross the Outer Marker. These altitudes will differ from the approach altitudes shown on your approach plates. The intent here is to descend using the VASI rather than fly a full approach. Intercept the descent path when the Outer Marker sounds, dashed tones, and a blue indicator light illuminating on the instrument panel. In most instances, the VASI lights will not be visible from the Outer Marker in Flight Simulator. Dont worry, start the planned descent at the Outer Marker. The VASI will pop into view very shortly. Note the RPM column at the end of the table. Record the engine RPM here for each flight after you have achieved a stabilized descent down the glide path. The point is to learn what engine RPM provides the proper rate of descent for your aircraft in the approach configuration of 75 kts., and one notch of flaps lowered. Then when you fly the full ILS you reduce your engine power to this RPM setting when intercepting the glide path. To minimize porpoising, smoothly reduce the RPMs when throttling back to descend. The digital tach readout allows you to precisely set the desired RPMs. Admin : Hamed
Posted on: Fri, 18 Oct 2013 10:24:54 +0000
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