# Tag Info

12

If a plane traveled $8\ \mathsf{cm}$ on a map with a scale of $1:1\ \mathsf{million}$, then it traveled $8\ \mathsf{million\ cm}$ in the real-world. $$8\ \mathsf{million\ cm} = 80,000\ \mathsf{meters} = 80\ \mathsf{km}$$ Convert 80 km in 18 minutes to a speed of kilometers per hour: \frac{80\ \mathsf{km}}{18\ \mathsf{min}} \cdot \frac{60\ \mathsf{min}}{...

10

Precision Approaches (PA), as you mention, have specific performance requirements, one of which is how "good" the vertical position measurement must be during an approach. In the case of a PA, ground systems either directly measure the aircraft's vertical position on the glide path (Precision Approach Radar in the case of parallel approaches), or provide a ...

8

The ICAO classifications have changed: (eurocontrol.int, 2017) ICAO has been reworking the approach classifications since c. 2012, because of the confusion they were causing in the PBN environment. Good news is, LPV SBAS Cat I is now (since at least 2013) a precision approach. Approaches now are two types, A and B. The approach minima are ≥250 feet and &...

5

Is GLS an RNAV approach? Short answer is no. It is also not in the framework of PBN. RNAV approach Out of confusion the naming was not standardized, which led to more confusion. This will be fixed, from 1 Dec 2022 only the term RNP will be permitted for the minima you mentioned. (ICAO Circular 336, starts at page 19) RNAV? It stands for area navigation, ...

5

When it is not stated, it means it is the nominal value of 2.5%, i.e., for the first example, the LPV climb gradient is 2.5%. When an additional OCA/H is published, then the OCA/H and gradient values are published (second example). From PANS-OPS: 6.2.2.2 Climb gradient in the intermediate phase. The nominal climb gradient (tan Z) of the missed approach ...

4

You are confusing some terminology. RNAV (GPS) approaches can have several different sets of minima. See the example RNAV (GPS) Y 28L at O'Hare: It has: LPV LNAV/VNAV LNAV sets of minima. LPV is an instrument approach procedure (IAP) with localizer-type precision and with vertical guidance, (hence the name LPV), provides a pilot with a "ILS-style" ...

2

First is understanding the difference between RNAV and RNP. This related question: What is the difference between RNAV and RNP? provides a basic answer to that part of your question. To your specific question, RNAV procedures predate the acceptance of RNP standards. Since RNP standards have been established as the basis of navigation, you should expect ...

2

RNAV(GPS) procedures being combined with LPV or LNAV/VNAV, which are Landing Systems Your confusion here is that LPV is a landing system which it is not. It is a way of saying your GPS is going to work kind of like an ILS and will have similar horizontal/vertical responses on your way down or as the FAA puts it Localizer Performance with Vertical ...

2

I will have to answer my own question, since I have noticed that in FAA's PBN Manual it states: PBN 8260.58A 1-2-5c . Turn parameters. For OEA construction, a turn is indicated when the course change exceeds the alignment tolerance of 0.03 degrees. So, at least as far as route design is concerned, the alignment threshold for turn indication is 0.03 ...

1

I think what you're talking about are what pilots refer to as "fly-past" and "fly-over" waypoints. Up until recently, all waypoints in the world were "fly-past", ie you could cut the corner from one leg to the next and not actually fly over the waypoint itself. This is still the standard, unless otherwise stated. But then some SIDs and STARs needed people to ...

1

Im more familiar with EASA then FAA but im sure there are similarities: why a desired ground track would require a smaller navigation accuracy value? RNP 2: the aircraft must be within ± 2 nm of the indicated position 95% of the flying time (Required for Basic RNAV). RNP 1: the aircraft must be within ± 1 nm of the indicated position 95% of the flying ...

1

There is a substantial distance between actual GPS/SBAS performance AND theoretical error modelling done to bound SBAS performance. In the real world, HPL/VPL (horizontal/vertical protection levels) are in the 15 meter levels while measured errors are in the 2-3 meters level, rarely getting to 10 meters. Actual errors are always 5-10 meters better than HPL/...

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