LDA/Glide Slope Approach: Precision?

MasterFly

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I heard that at the ACA interview, they ask about an LDA/Glide slope approach, namely the LDA 6 in ROA. It is so hard to get a straight answer. The FAR/AIM says that an approach with an electronic glide slope (like this approach) is a precision approach, but many say since it is an LDA, it is still not precision. I can't make up my mind. This LDA does have a glide slope, but the course is about 10 deg. off the runway, so maybe it is not.

I was hoping Avbug could enlighten us on this!

Here is a previous post about this argument:

http://forums.flightinfo.com/showthread.php?s=&threadid=5583&highlight=lda
 

hyper

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walkthasky

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...

**CENSORED****CENSORED****CENSORED****CENSORED** that was some argument...
It still leaves the question in the air, because everyone's answer is justified. I personally think they ask the question to see your rational with it.

p.s. im going with precision..hehe
:D
 

pilotyip

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look it up

This whole topic was discussed about a month ago on this board, and fairly well defiend. I took the interview at ACA in 1996 and was asked the same question, I told the interviewer it was a non-precision approach because of runway line up, I was offered a job, he must have liked my answer.
 

avbug

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14 CFR 1.1 clearly states that any standard instrument approach proceedure in which an electronic glideslop is provided, is a precision approach proceedure:

"Precision approach procedure means a standard instrument approach procedure in which an electronic glide slope is provided, such as ILS and PAR."

Alignment with the runway is not material to the question; precision is determined by the availability of both lateral and vertical guidance to a point in space (MAP at DA/DH). That particular point may be higher than standard, or farther from the runway than standard due to alignment issues, but that doesn't change the fact that precision guidance has been provided to that point.

An LDA proceedure without vertical guidance is a non-precision proceedure. An LDA proceedure with electronic vertical guidance (eg, glideslope) is a precision proceedure.
 

walkthasky

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well said...
 

flywithruss

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Not that simple ...

It takes more than Part 1 to answer this question ... to really research it requires an understanding of the rules governing instrument approach procedures when they're created. Yes, an approach must have electronic lateral AND vertical guidance to be precision. That's not enough, though. By that definition, an LDA-A (w/ GS) would be precision, even though it publishes NO straight-in minima. You just can't do a circling precision approach, by definition.

The rest of the definition requires alignment with the runway centerline, not to mention strict standards of course guidance, signal width, and the degree of accuracy of the signal involved. As a result, the ONLY precision approaches out there are ILS, MLS, and PAR ... GLS (precision GPS approaches) and TLS (transponder landing system) are likely to join the list in the near future.

To answer the original question, the LDA 6 at ROA is a non-precision approach, forever and ever, amen. The LDA/DME 19 and Rosslyn LDA 19 approaches at DCA (both of which have glide slopes associated) are also non-precision approaches. No LDA is ever precision, no matter what, because it does not provide the required alignment with the runway centerline. If it did, it would be an ILS! Some of us remember the old Kai Tak approach, the IGS 13, it was called (the "checkerboard" approach). Watch those airplanes (who had lateral and vertical electronic course guidance, per FAR 1) make that 47 degree turn to align with the runway at 300 feet and tell me how that is a precision approach!

I thoroughly understand the confusion here, but I've reached my conclusions only after discussing the matter in some detail with folks from two FSDOs as well as a good friend who is a DPE, and has also discussed it with the folks out in OKC.

These discussions are why I love this board ... I learn something new every day, and on a good day, I get to share it with the group.

Tailwinds, y'all ...

R
 

The FNG

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I agree that an LDA approach with or without a GS is technically a non-precision approach. However, when there is a GS associated it is flown like a precision approach (with the exception of autopilot minimums). Both the FAF and MAP are determined using precision approach conventions rather than non-precision, and I believe this is what really matters.
 

flydog

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In our Op Specs an LDA without vertical guidance is classified under Non-Precision. LDA with vertical guidance is classified as a "precision-like" approach whatever that means. In any case we are only authorized non-precision LDAs under 135 per our op specs
 

MasterFly

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Thank you for your responses. I think this can be debated forever. According to FAR Part 1, it defines it as a precision approach, but it is still hard to call it one.

There is an LDA approach to DCA where there is a glide slope, but it takes you only to an MDA where you then have to fly around a building and fly visual down the river to the runway.

According to Part 1, it has a glide slope and is precision, but how can you really justify that this is a precision approach?
 

avbug

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"You just can't do a circling precision approach, by definition."

Oh yeah? What definition?
 

pilotyip

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Check rides

both 121.441 and 135.297 require pilots to demonstrate proficiency in all precision approaches the company uses on every Proficiency Check. If the LDA/w GS was a precision approach every company pilot would have to shoot one every check ride along with the ILS and PAR if authorized by the op specs. We do not demonstrate proficiency in the LDA because it is a NPA.
 

avbug

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Neither Part 121 nor Part 135 require that a pilot demonstrate all precision approaches authorized on every checkride. During a proficiency check, a pilot in command must execute at least one normal ILS approach, and one with a simulated engine failure. The pilot must also execute a non-precison approach.

You refer to 121.441, which uses Appendix F of Part 121 as the guide, the relevant portion copied below. In no way does it state that every precision approach must be executed, for which an operator is authorized. Regardless, this does not define the nature of a precision approach. The definition of a precision approach is specified in the opening part to 14 CFR.

A precision approach is clearly defined as one having vertical guidance, while a non precision approach is clearly defined as one that does not have vertical guidance, as previously given. How much more clear can this be?

Part 121, Appendix F, subparagraph (c):

(c) ILS and other instrument approaches. There must be the following:

(1) At least one normal ILS approach.

(2) At least one manually controlled ILS approach with a simulated failure of one powerplant. The simulated failure should occur before initiating the final approach course and must continue to touchdown or through the missed approach procedure.

(3) At least one nonprecision approach procedure that is representative of the nonprecision approach procedures that the certificate holder is likely to use.

(4) Demonstration of at least one nonprecision approach procedure on a letdown aid other than the approach procedure performed under subparagraph (3) of this paragraph that the certificate holder is approved to use. If performed in a training device, the procedures must be observed by a check pilot or an approved instructor.

Each instrument approach must be performed according to any procedures and limitations approved for the approach facility used. The instrument approach begins when the airplane is over the initial approach fix for the approach procedure being used (or turned over to the final approach controller in the case of CA approach) and ends when the airplane touches down on the runway or when transition to a missed approach configuration is completed. Instrument conditions need not be simulated below 100 feet above touchdown zone elevation.

Regarding 135.297, it would appear you alluded to subparagraph (b), which states:

"(b) No pilot may use any type of precision instrument approach procedure under IFR unless, since the beginning of the 6th calendar month before that use, the pilot satisfactorily demonstrated that type of approach procedure. No pilot may use any type of nonprecision approach procedure under IFR unless, since the beginning of the 6th calendar month before that use, the pilot has satisfactorily demonstrated either that type of approach procedure or any other two different types of nonprecision approach procedures. The instrument approach procedure or procedures must include at least one straight-in approach, one circling approach, and one missed approach. Each type of approach procedure demonstrated must be conducted to published minimums for that procedure."

This is not to be construed as meaning that a pilot must demonstrate every approach authorized that operator. However, if a pilot wishes to execute a precision proceedure that is authorized to that operator, then he or she must have demonstrated it within the preceeding six callendar months.

As we discussed by PM, your ops specs do not place an LDA with a glide sloope under the heading of non-precison, as this was changed two years ago to a heading describing approaches other than an ILS, MLS, GLS, etc. This is an important distinction, and it was made with the intent of recognizing the upcoming of other types of precision approaches, or approaches which are not nonprecision.
 

pilotyip

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135.297 (b)

135.297 (b) No pilot may use any type of precision instrument approach procedure under IFR unless, since the beginning of the 6th calendar month before that use, the pilot satisfactorily demonstrated that type of approach. got to on 135.
 

avbug

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I belive that's what I quoted. What's the point?
 

pilotyip

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Must shoot the PA

That is what I said, you said I did not have to shoot every PA in my op specs, my POI says we must demonstrate proficieny in every PA in our Op specs. she and her FSDO call the LDA/w GS a NPA.
 

avbug

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No, Pilotyip, this is not correct. You do not have the power or authority to interpret the FAR; neither does your POI, or anybody at the FSDO level.

You are NOT required to demonstrate every approved precision approach in your opspecs. You may not fly an approach you have not demonstrated in the previous 6 months, but nowhere under Part 135 are you required to fly every approach. If you don't demonstrate each precision approach, you may not fly it, but there is NO requirement to demonstrate it, or to later fly it. If you don't demonstrate it, you're simply restricted from flying it.

Do you demonstrate a MLS approach every 6 months?

Part 121 doesn't require even this; only the three approaches as given in my previous post, and quoted from Appendix F.

The CFR, however, is legal evidence of itself, as a codification that stands alone without specific constitutional reference or enpowerment. Being self-evidentiary, the provision of definition set forth in 14 CFR 1.1 is ample description and conclusion as to the nature of an approach that includes vertical guidance.

What does that all boil down to? Your OpSpecs don't define the FAR, or the terms set forth in the FAR. Your POI doesn't have the ability to do so, either. Neither does a soul at your FSDO. The power and authority to do so is not granted at that level.

Any classification in your OpSpecs does not define the FAR, nor does it define TERPS. The OpSpecs do not clarify or represent the FAR, nor may they be used as evidence to interpret the FAR. How should one view an approach if one does not work for a certificate holder, and has no OpSpecs? Would your OpSpecs be applicable to such a person? Of course not. However, 14 CFR 1.1 would be, and is.
 

pilotyip

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MLS

can not do MLS or PAR or ASR, not in our ops specs, you are telling me a FSDO can not define how it views the regs? An LDA with gs is a NPA
 

The FNG

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Avbug,

This is a bit off the original subject, but since it came up I have a question. You stated that "Opspecs don't define the FAR" and "do not clarify or represent the FAR" but 121.625 Alternate airport weather minimums states in part that, " weather conditions will be at or above the alternate weather minimums specified in the certificate holder's operations specifications".

Isn't this an example of Opspecs defining an FAR?

Because my Opspecs define LDA w or w/o GS as nonprecision then for me, and everyone at my company, it is nonprecision.

The LDA issue is a matter of semantics. What difference does it make what you call it as long as you know how to fly it and how to make decisions based on your understanding of the approach.

My.02
 

avbug

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When the OPSS provides information or direction to an operator, it is binding to that operator, only. Takeoff minimums and alternate minimums may vary, according to the pilot qualifications and experience, as well as the operator limitations. This doesn't redefine the FAR, but only provides on an individual basis the limitations for a given operator or pilot. This is the purpose of OPSS, or OpSpecs.

OpSpecs are approved data, meaning data approved by the administrator for a particular purpose In this case, for a particular operator, and a finite group of pilots. OpSpecs do not define the FAR.

As for inspector opinions and the FSDO...yes, I mean exactly what I said. The FSDO does NOT have the right or authority to interpret regulation or to issue interpretations. The FSDO has the authority to initiate enforcement action (but not to follow through or complete that action).

Does your OPSpec C052 classify an LDA w/gs as nonprecision, or does it classify it under "Instrument Approach Procedures Other Than ILS, MLS, and GLS?" It should include in parenthesis "(eg, nonprecision approaches)." This change was made two years ago, and has been referred to several times here.

According to HBAT 99-17, "C. The general classification of "nonprecision" was replaced in order to recognize current and future authorizations for RNAV and other approaches that may incorporate the use of barometric VNAV to provide a stabilized descent."

Be that as it may, the OPSS doesn't define the FAR. What may be for you, or for your company, is not for everybody. The OpSpec doesn't represent an interpretation, but a set or restrictions and limitations applicable only to the user. Any classifications therein are not evidence of the FAR, and OpSpecs can't b used to define TERPS or Part 97 of 14 CFR.
 
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