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Guest AirForcePilot

Approach Problem

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Guest AirForcePilot

Hey all. Last night I flew the PMDG 737-800 from ATL to DCA. DCA has and LDA approach for RWY 19. RC told me to expect vectors to RWY 19....they didn't mention they were giving me an approach. FS 2004 has the LDA and for anyone that doesn't know, and LDA is like a localizer approach except that the localizer is slanted up to I believe 30 degress from the end of the RWY. In RL they use the LDA to 19 because a straight in approach would pass over the White House which is Prohibited airspace. Anyway, RC set me up with vectors to intercept as if it was a straight in approach. After the controller cleared me for the approach I had to make a huge right turn so I could intercept the LDA based on what my FMC was depicting. After making about a 70 degree turn to the right I was able to intercept the localizer and fly the approach. Anyone else ever experience this problem? Thanks.

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Hi,Rather sure the approach heading is offset by about 40 degrees from the actual runway heading.The glidepath angle should still be about 3 degrees.The LDA's are especially popular where you have to like fly between mountains for terrain advoidance.Guess you have to tell RC you need to fly it manually (FMC).Best Regards,Vaughan Martell

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Guest Douglas Thompson

I think I've tried that apch into KDCA. Respect to logical vectoring, RC crashed and burned horribly with that localizer offset. I don't see addressing such issues in v5 given the few approaches with that sort of offset. v5 will have alot more meat to it. In KDCA's case though, use IAP (and the FMC if you wish). That's what I did (and still screwed the approach up :D

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Guest AirForcePilot

Straight in minimums with the LDA only apply when the course doesn't exceed more than 30 degrees. If its more than 30 then only circling minimums apply. And yes, LDA's are used for a number of things including terrain avoidance.

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Guest AirForcePilot

Yeah I suppose that'll work. I've shot an LDA in RL and they're much easier in the actual plane then they are in the sim. You're right though, with so few LDA's in existence I wouldn't make it a top priority for V5.

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There are two RWY 19 LDA approaches. The LDA/DME uses a different localizer and does not tune a glideslope. The ROSSLYN LDA has aanother localizer with paired glideslope and lower minimums.Either way an IAP is necessary. The runway data file uses a heading of 185, which is what RC uses for vectoring but the localizer is at about 142. The way to get around this far down the road is to have makerwys provide the heading of the localizer which would then be the reference for vectors, not the runway heading. That would take care of merging with those weirdo offset approaches.Also for 19 at KDCA, the frequency given in r4 is for the approach without the coupled localizer/GS. The AFCAD is wrong for rwy 19 as the properties show a GS for both which probably confused makerwys.Just a bit of trivia.

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