LDA w/Glideslope

[CRJCptn]

If you have to manuver to join final, can it really be precision?

 

[JettBoii]

I missed the 1.1 but just read it and it does say that a precision approach has a glideslope "like a ILS or PAR". The definition if a non precision is one that has no glide slope; the LDA/GS of course does.

What would you say on an interview?

 

[peter185]

The LDA is of comparable utility and accuracy to a localizer but is not always aligned with the centerline of the runway. Terps requires the localizer signal alignment with 3 degrees of the runway alignment. If the alignment exceeds 3 degrees, the localizer will be identified as an LDA.

Once designated as an LDA, the max angle of convergence of the final approach course and the extended runway centerline is 30 degrees. The signal accuracy of the LDA is the same as a Localizer, however the LDA course alignment will be greater than 3 degrees, not to exceed 30 degrees. Straight-in minima can be published only where alignment conforms to the straight-in criteria. Circling minima are published where this alignment exceeds straight-in criteria.

The LDA is usually considered a non-precision approach; however, in some installations with a glide slope, a decision height will be published. If a decision height is published, it can be flown just like an ILS approach.

 

[JettBoii]

1-1-9 C) #3 - LDA/Glideslope falls under the APV category (approach with vertical guidance).

5-4-5 7.(b) - APV approaches based on a navigation system that is NOT required to meet the precision approach standards of ICAO annex 10.

 

[avbug]

If you have to manuver to join final, can it really be precision?

That's really irrelevant, but to reply, yes. ILS approaches frequently require maneuvering to join the final approach course, too.

What your OpSpecs say is also irrelevant. OpSpecs do not define the regulation, and only apply to your company operations.

The AIM does provide a definition that has been given. Until recently, any approach with a glideslope was precision. The LDA with a glideslope contrary to popular belief, was a precision approach. It is now considered "precision-like" due to an expansion in the definition.

 

[CRJCptn]

I worded my last statement badly. I sould have said manuvering at minimums, not final. sorry...

 

[Amish RakeFight]

Perhaps it has been changed, but I affirmatively recall reading in the AIM a long while ago that the LDA/GS is NOT considered a precision approach.

 

[AC560]

Where this has become relevant from my perspective is that WAAS allows for GPS only airports to be alternates. So if you are part 91 it makes a difference as to which it is for alternate minimums (600/2 or 800/2).

AIM 1-1-20
(a) Due to initial system limitation, there are certain restrictions on WAAS operations. Pilots may plan to use any instrument approach authorized for use with WAAS avionics at a required alternate. However, when using WAAS at an alternate airport, flight planning must be based on flying the RNAV (GPS) LNAV minima line, or minima on a GPS approach procedure, or conventional approach procedure with "or GPS" in the title. Code of Federal Regulation (CFR) Part 91 nonprecision weather requirements must be used for planning. Upon arrival at an alternate, when the WAAS navigation system indicates that LNAV/VNAV or LPV service is available, then vertical guidance may be used to complete the approach using the displayed level of service. The FAA has begun removing the

NA (Alternate Minimums Not Authorized) symbol from select RNAV (GPS) and GPS approach procedures so they may be used by approach approved WAAS receivers at alternate airports. Some approach procedures will still require the

NA for other reasons, such as no weather reporting, so it cannot be removed from all procedures. Since every procedure must be individually evaluated, removal of the

NA from RNAV (GPS) and GPS procedures will take some time.

So whatever it is classified as it would seem to indicate that it needs to be considered as non-precision for planning purposes.

 

[avbug]

WAAS has nothing to do with an LDA approach with a glideslope. What are you talking about?

 

[AC560]

WAAS has nothing to do with an LDA approach with a glideslope. What are you talking about?

No but whether a LDA approach with a glide slope is precision or non-precision is necessary to know to determine if an airports weather is suitable for use as an alternate. This is especially true when the airport is only served by a GPS approach (which WAAS allows for).

I can't really think of any other reason why you would care if it is precision or non-precision (aside from taking the requirements of the instrument PTS). The relevant AIM section shows that for alternate planning you consider non-precision which means 800/2.