IFR LOC/DME APP HELP!

[TheAlchemist]

So here's my question about this particular LOC/DME app in Fullerton:

The mins are S-24 560-1 . I-FUL is 0.5 dme wich puts acft by taxiway Echo (the last one before reaching rny 06). Now even if I'm 1 dme from the DME at 560 ft that would still make it almost impossible to land the acft considering rny 24 ldg dist is only 2868 ft.

Here is the app for FUL:

Approach

What I'm asking is if a go to mins it will be impossible to land the plane so I'd have to go missed. What am I supposed to do in this case (besides going missed)? Should I use 1.5 dme as reference?

Thanks for your help

[Doug Taylor]

You've really got to compute a visual descent point. The missed approach point doesn't necessarily always bring you to a position where you can complete a normal landing.

[meritflyer]

Originally Posted by Doug Taylor

You've really got to compute a visual descent point. The missed approach point doesn't necessarily always bring you to a position where you can complete a normal landing.

Correct.

Take the HAT and divide it by 300 to compute your VDP in terms of distance.

Once you reach the VDP, you must be able to have the items listed in 91.175(c)(3) in sight to descend below the published MDA using a normal descent rate.

[Doug Taylor]

And if you're past the MAP, you're doing a 'rejected landing' so check the ODP.

[meritflyer]

Originally Posted by Doug Taylor

And if you're past the MAP, you're doing a 'rejected landing' so check the ODP.

Or the missed approach procedures.

[Doug Taylor]

At least the way my airline trains, you start the missed approach procedure no later than the missed approach point.

If you're dorking around looking for the airport AFTER the MAP, you may or may not meet the TERPS criteria for obstacle clearance so you revert to the ODP.

[TheAlchemist]

I see...so if I set my VDP at (eg. 1.5 dme in this case) and when I get there I don't see the rny environment then just continue to 0.5 and go missed from there unless I see the rny envmt at ( eg 1.2 dme) and determine that I still can make a safe landing then I could continue for the ldg...right?

Thanks a bunch!

[Doug Taylor]

Basically, in the old days of the 'dive and drive', we'd compute a VDP, start a 3:1 descent to the VDP and if we didn't see the airport, start climbing on final approach course, hit the missed approach point and then conduct the missed approach procedure.

[meritflyer]

Originally Posted by TheAlchemist

I see...so if I set my VDP at (eg. 1.5 dme in this case) and when I get there I don't see the rny environment then just continue to 0.5 and go missed from there unless I see the rny envmt at ( eg 1.2 dme) and determine that I still can make a safe landing then I could continue for the ldg...right?

Thanks a bunch!

Exactly.

On a sidenote, dont attempt a chop and drop close to your MAP. Remember you need to be in a normal position to land using normal maneuvers (no more than a 1000' FPM descent). If you get too close to the runway, go missed or simply (and weather permitting) go around for another approach.

[TheAlchemist]

Originally Posted by meritflyer

Exactly.

On a sidenote, dont attempt a chop and drop close to your MAP. Remember you need to be in a normal position to land using normal maneuvers (no more than a 1000' FPM descent). If you get too close to the runway, go missed or simply (and weather permitting) go around for another approach.

Got it! Thank you!

J/C kick a$$...you guys just saved me .2 hr of ground instruction plus last time my cfii didn't have a definite answer for that

[Doug Taylor]

That's why we're here!

[fish314]

A good memory jogger for computing the missed approach is "Gus wears a Hat".

Basically that's HAT/GS, or Height above terrain/Glideslope.

Now, you're legal to stay at the MDA all the way up to the MAP, and if you see the runway and are in a safe position to land using normal procedures, you can still land. (Even if you are after your VDP).

But LOTS of approaches put the MAP very close to, or right over, the runway threshold. The only way you'd be in a safe position to land is if you were able to accept a long landing... Say for example you are landing on a 12000 foot long runway, and your landing distance was only a couple thousand feet. In that case, it might be no problem to land 4 or 5 thousand feet down.

But obviously that wouldn't work on a "short" runway... Using whatever you'd consider "short" for the type of aircraft you're flying.

[deadstick]

One "gotcha" with the GPS:

If you select the LOC/DME approach in the IFR/APPR GPS "for situational awareness" and to use the GPS ILO DME, watch out for the distance. I've seen many people execute the missed too early. The GPS will probably have the final segment of QEWTI - RW24. The distance shown on the GPS will be FROM RW24, the approach end of Runway 24. The step downs (like at CONGA) and the MAP are based on I-FUL. In this case, pilots would descend for the step-down or go missed about 0.5 nm early. For the GPS to be used ILO the DME, the LOC has to be the active waypoint. This is one reason you get the warning while loading the approach that does not have a GPS overlay.

Look at the 439 +/- ft tower outside of CONGA. If you step down early to 560 ft, the altimeter is 74.5 ft off, you're a bit rusty and are north of course and a little low, and there is some turb...bad stuff, Maynard.

[Timbuff10]

Wow, you guys really picked apart that approach. I never really thought about picking a VDP for an approach like this. I figured you just use a normal descent rate and drop down to 560 after CONGA and if you didn't see the runway environment by then, it is time to go missed and set up for the ILS at SNA or LGB.

Good reading though... We need more of this!

[meritflyer]

That is one way to do it per se but it is a MDA not a DH.