LDA Approach

[skydrvr]

On LDA approach with a glide slope is this a prec. or nonprec. approach.

 

[VelcroJetDriver]

If electronic vertical navigation is provided from a ground-based transmitter from the FAF to the MAP, it is a precision approach

 

[flyinhard]

I thought that you needed to have an approach that was within 30 degrees of the runway and have vnav. I don't believe that an LDA goes outside of this 30 degrees for the most part. There are some that run you to the run perpindicular, but to answer your question, as long as you break out 30 on either side of the runway and have vnav for the approach, it would be considered precision.

 

[pilotyip]

NPA

It is a non-precision approach because it does not align with the runway within 2.5 degrees on centerline. This comes from the FAA via our POI. We list the LDA w GS as a non-precision approach in our Op Specs. If it was listed as a precision we would have to shoot one on ever check ride to stay current.

 

[flywithruss]

Non-precision!

The LDA/GS approach is non-precision ... to qualify as precision, an approach must have sufficiently sensitive lateral and vertical guidance (for this reason, an SDF with GS ... if there is such a thing ... would be non-precision as well ... signal width provides half the sensitivity of a localizer), and align the user with the runway w/in 2.5 degrees ... the 30 degrees alignment from a prior post differentiates between a straight-in and circling approach.

I've had this discussion a few times with a good friend of mine who is a DPE, as well as with SPMs from two different FSDOs, and the answer was unanimous.

Take a look at some specific IAPs and think this through ... good examples off the top of my head include the LDA/DME and Rosslyn LDA 19 approaches at DCA, the LDA 6 at ROA, and the LDAs to 12L and 30L at STL. By the way ... these are all installed for different reasons ... good teaching tools for CFIIs out there ... I used them all the time for instrument students.

Tailwinds, y'all ...

R

 

[ALGFLYR]

I would argue that a LDA with a glideslope IS a Precision Approach. Under the definition in your Jepps (page 9 - intro tab) it defines a precision approach as: " A standard instrument approach procedure in which an electronic glideslope/glidepath is provided". Using that definition, it would classify as a precision approach.

Also, if you look at a LDA approach with a glideslope (for example: the LDA Rwy 6 in ROA), it lists a DA as opposed to an MDA. And the definition of a DA is "A specified altitude or height in the PRECISION approach at which a missed approach must be initiated..." Reference page 4 in the intro tab of your Jepps.

The mystery continues....

 

[Timebuilder]

Years ago, an instructor taught me that vertical guidance meant precision, and that only a precision approach had a DH.

Who has the answer?

 

[gump88]

I have been asked this question several times at interviews. I always answered "precision". Never been turned down for a job - 4 times.

It has vertical NAV and a DH ------- PRECISION! An LDA has the same lateral sensitivity as an ILS. It is just not aligned with the runway centerline. That is why you will not see an LDA/GS approach to a DH of 200 AGL.

gump

 

[pilotyip]

Interviewers

could be the interviewers did not know the answer, or your strong points overcame the answer on this question.

 

[flx757]

An LDA approach, regardless of whether or not it has a GS, is a NON-PRECISION approach.

Period.....End of discussion.

 

[gump88]

Re: Interviewers

could be the interviewers did not know the answer, or your strong points overcame the answer on this question.

PILOTYIP,

That is very possible. However, I have always been taught that it is a PRECISION approach. If you ask 3 different POIs or DEs a question about any specific FAR you will likely get 3 different answers! I will continue believing that an LDA/GS is a precision approach. By the way, a PAR is not an ILS but is also a PRECISION approach. Take away the GS and they are both non-precision.

gump

 

[gump88]

An LDA approach, regardless of whether or not it has a GS, is a NON-PRECISION approach.

Period.....End of discussion.

Then next time you shoot one, use the MDA for the GS out minimums instead of the lower DH with the GS! That way you will have your NON-precision approach.

 

[flx757]

Re: Re: Interviewers

If you ask 3 different POIs or DEs a question about any specific FAR you will likely get 3 different answers!

gump

That may very well be true, however if you consult the AIM or, if you fly for a 121 carrier your ops specs (Para C052), regarding this particular question, you will get the SAME answer. That an LDA is a non-precision approach...glideslope or no glideslope.

There are 3 "precision approach systems"; ILS, GLS, and MLS.

The PAR is also a precision approach but is based on radar.

Once again, and finally...an LDA is a non-precision approach. The fact that there may be a glideslope associated with it does not make it a "precision approach system".

 

[gump88]

Re: Re: Re: Interviewers

That may very well be true, however if you consult the AIM or, if you fly for a 121 carrier your ops specs (Para C052), regarding this particular question, you will get the SAME answer. That an LDA is a non-precision approach...glideslope or no glideslope.

There are 3 "precision approach systems"; ILS, GLS, and MLS.

The PAR is also a precision approach but is based on radar.

Once again, and finally...an LDA is a non-precision approach. The fact that there may be a glideslope associated with it does not make it a "precision approach system".

True, the ops specs state that an LDA approach is non-precision, but I cannot find where it says "glideslope or no glideslope." This section, Para C052, is referencing a stand-alone LDA approach. I believe according to definitions already posted on this thread, adding a GS makes it precision.

Lets just agree to disagree on this subject!?!?

Respectfully,
gump

Former 121 puke - 8 years