Don't Fall for a False Glideslope! | ILS Glideslopes Explained

[Dante_Vicino]

Best advice ever given to me was to make sure that you're arriving at the FAF at the right altitude and not pay attention to any other GS indication before then.

[cobra]

Don't forget about the FAF Altitude cross check! I'm not sure about in the USA, but in many other places not crosschecking your altitude at FAF is a check ride bust

[ahmadsamadzai]

As usual the best content on yt. Thank you Dan.

[pilot_in_commend]

Hi there. Another masterpiece. We just discussed the false GS phenomenon with my subscribers few days ago.
Speaking, I thrown a couple of email but unfortunately no reply. I seek for your permission to translate a bunch of your educational videos into Russian for my audience. Some of are just aviation enthusiasts, some of them - potentially future pilots in US. But the most of them are Russian-speaking. I'd like to have some of your videos translated into Russian to cover some topics we discuss during my live streaming events or in other social media. I'll put the link to the original video/channel in the description and will encourage my audience to learn in in English rather than interpreted materials, however it would be a good start for them. What do you think?

[markdawson]

Dan - After locking in on a false GS signal, but subsequently descending to the proper altitude prior to crossing FAP, will the instrument release that false signal and acquire the proper 3 degree slope? Or does it stay “locked” onto a false reading?

[jimallen]

Excessive elevator pressure to maintain descent (on the false glide slope)?!? You mean excessively reduced power! 

Perhaps even an inability to pull sufficient power. Such also reveals itself both manually and coupled presuming no auto-throttles. Even with auto-throttles, they may be limited so as to cut out for need being excessively reduced

Though, correct, for both manual and auto/auto-throttle, VVI will reveal the correct beam. If you’re doing 90 kts GS, your VVI is 450 fpm. At 120 kts, it is 600. And, intercepting from below really does remove the problem. As does knowing proper altitudes to range remaining assuming you have dme, 300 feet above touchdown per mile to go.

Now, go have a look on Medium for AOA and power techniques followed by its case study with F-35C crash in the South China Sea. Airplanes descend with reductions in power; they dive if you push the nose down. Descents are adjustments in chemical energy rates to change potential energy. Dives are trades PE for KE. Similarly, climbs are CE for PE while zooms are KE for PE. You should be using power techniques excluding airplanes with excessive spool-up times like certain turbine platforms. Even with these, you’re going to have to adjust power so as the dive won’t get away from you thus converting the dive to descent and therefore even in these, it is with excessive power not stick pressure for which you will likely sense being too steep. Excessive stick pressure means you are going too fast. But, yes, VVI will quickly illuminate.