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During a recent sim session this happened:

ILS radar vectors I armed the approach late initially the aircraft went left and right but it captured the LOC but the G/S was not captured.

Could someone please help me out?

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FreeMan
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Deepak
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1 Answers1

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It sounds like you were high on the glideslope & getting higher by the time you got VOR/LOC capture. At that point, the GS typically won't capture unless you do something to get it centered again.

As a fix, if your procedures allow it, you could set a lower altitude such as localizer minimums into the MCP altitude window and then command a descent in Vertical Speed mode. That could get the GS centered, at which point the GS would capture, and you're back in business. It is entirely possible to capture the GS from above this way, but it has to be pretty well centered. If you're above it, the system won't dive down to capture it on its own.

Ralph J
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  • Sounds like quite the stabilized approach? Depending on how far out the GS is recaptured, it could be considered stabilized but it isn't starting out too well. – wbeard52 Mar 15 '24 at 02:20
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    @wbeard52 Definitely not the ideal case, but in the sim, like the real world, such things can happen. If a bad vector from ATC means you capture the LOC slightly inside the FAF but you're 9 miles out at 3,000' above the runway, you have plenty of time to do what I described & you'll be stable well before 1,000'. If you're trying to sort this all out at a 1,400' GSIA, well, that gets more sporty. As a matter of kicking off the automation & hand flying it, if you're comfortable with that, it'd probably be the best bet, but if that's not comfortable... going around may be the best option. – Ralph J Mar 15 '24 at 03:29
  • I agree with you. It is more important to be stabilized and there may be time to get stabilized by 1,000 FT AGL. I don't necessarily think sim instructors do a great job of instilling ADM and wanting the crew to go-around when the approach becomes unstabilized due to time factors and the need to finish checking the boxes. – wbeard52 Mar 15 '24 at 15:23
  • Hey yeah Ralph hit the nail on the head. you seemed to be above the glideslope and the aircraft was not able to change from "GS arm" (GS in white) to "GS active" (Green). A great way to get down is to use VS an put in about 1500-1800 to capture the GS. But be aware, it is poor form to have a VS that exceeds your altitude in AGL. – Scott Pearce Mar 23 '24 at 18:41