pilotrobbie wrote:
Good points noted. Presumably an RNAV approach rather than an NDB? or would that be 3 approaches? ILS, NDB and RNAV?
To my understanding all RNAV approaches in the UK are classified as non-precision (even the few LPV ones?) and hence yes you’d do one precision (ILS) and one non-precision (RNAV).
The choices are often simplified by a mixture of
TimR wrote:
Verifying the GPS is functioning correctly
Correctly verifying that the GPS database on your navigator matches the plate
Ensuring that the GPS is flying the approach to the correct level of accuracy / is in the correct approach mode
Dealing with loss of integrity on approach (pre/post final fix)
Flying an RNAV missed
One step is missing. There are a number of ways (website, panel in the GPS) that allow you to predict whether the satellite constellation at any given point in time/space is good enough, meaning sufficient satellites visible sufficiently high above the horizon, for LPV or other approaches. This is called RAIM prediction. If you do it properly, like on your IR exam, you go to the website beforehand and take the data with you to the exam.
https://augur.eurocontrol.int/ec/terminal-approach
(More practical people just wing it – if RAIM prediction fails you just fall back to a less critical PBN approach: LPV → LNAV/VNAV → LNAV+V → LNAV. This normally leads to higher minima though.)
BackPacker wrote:
One step is missing. There are a number of ways (website, panel in the GPS) that allow you to predict whether the satellite constellation at any given point in time/space is good enough, meaning sufficient satellites visible sufficiently high above the horizon, for LPV or other approaches. This is called RAIM prediction. If you do it properly, like on your IR exam, you go to the website beforehand and take the data with you to the exam.https://augur.eurocontrol.int/ec/terminal-approach
(More practical people just wing it – if RAIM prediction fails you just fall back to a less critical PBN approach: LPV → LNAV/VNAV → LNAV+V → LNAV. This normally leads to higher minima though.)
If you have SBAS, you don’t need to do RAIM prediction. (But you do need to check NOTAMs for SBAS unavailability.)
@BackPacker although I agree with you that one should be able to do a manual RAIM check – on most modern avionics with SBAS equipment this is not required. Not even on an exam.
You would state pre-flight:
@Airborne_Again – or as you put it more concisely. Good timing 
TimR wrote:
To my understanding all RNAV approaches in the UK are classified as non-precision (even the few LPV ones?) and hence yes you’d do one precision (ILS) and one non-precision (RNAV).
No, that’s not correct. The revisions to the ICAO approach classification differentiate between approach procedures and approach operations.
Approach procedures are:
Non-precision: LOC, NDB, VOR and RNP with an LNAV minima line
Approaches with vertical guidance: RNP with an LNAV/VNAV minima line and most RNP with an LPV minima line
Precision: ILS, RNP with GBAS (“GLS”) and some RNP with an LPV minima line (“SBAS Cat I”)
Approach operations are:
3D: flown with continuous vertical guidance, i.e. a vertical deviation indicator
2D: flown without continuous vertical guidance, i.e. with the levels managed manually, e.g. using a level-distance table based on DME
It’s possible to fly a non-precision approach as a 3D approach operation, e.g. using Garmin’s LNAV+V advisory guidance, or an FMS.
The revisions to the skill test and prof check introduced with the PBN changes to FCL (2016/539) now require each skill test or prof check to include one 3D approach operation and one 2D approach operation (and for PBN privileges, one of them must be RNP). That could be an ILS and an RNAV to LNAV minima, or it could be an LPV and an NDB.
@bookworm very interesting. So to put it slightly differently, you agree most RNAV/RNP approaches (even some to LPV minima) are non-precision in the UK but since the exam requirement is 3D + 2D you can theoretically do LPV + NDB or LPV + VOR/DME for a checkride.
I guess that means you could even do a VOR/DME for the 2D part and an LNAV+V (Garmin creation available for thousands of airports) for the 3D approach?
So to put it slightly differently, you agree most RNAV/RNP approaches (even some to LPV minima) are non-precision in the UK but since the exam requirement is 3D + 2D you can theoretically do LPV + NDB or LPV + VOR/DME for a checkride.
I agree if you change a word: “most RNAV/RNP approaches (even some to LPV minima) are not precision approach procedures”. But they are not “non-precision approaches”. There are 3 types of approach procedure, and RNP to LNAV/VNAV or LPV minima fall under the middle category of “APV”.
Indeed yes, VOR/DME for the 2D part and an LNAV+V is compliant with the test protocol. If the LNAV+V DH is 700 ft though, you may find your examiner would rather you demonstrate something where the needles get a bit more twitchy…
TimR wrote:
To my understanding all RNAV approaches in the UK are classified as non-precision (even the few LPV ones?) and hence yes you’d do one precision (ILS) and one non-precision (RNAV).The choices are often simplified by a mixture of
not being equipped with an ADF
plane only certified for LNAV or LNAV+V (automatically non-precision)
the likely exam route airport not having an NDB approach
I presume even with ADF equipped, most examiners (although don’t quote me on that) are looking at GPS based approaches as the secondary approach on an IRT?
Standards Document 1 – Section 5. Point 3.6.16 – Precision Approach (Section 4) & Non-precision approach (Section 5) says the following;
The non-precision approach requirement may be met by NDB, VOR, RNAV or Localiser only procedures as briefed by the examiner. A RAIM check must be completed prior to any RNAV GNSS approach (before or during flight). Any published RNAV approach will be treated as a procedural approach for test purposes and all information required to fly the procedure, including moving map displays, may be used. However, where a moving map is available for a GNSS approach, the examiner should assess the applicant’s situational awareness and tracking by using “conventional” instruments at some other stage of the flight. This might be achieved, for example, by briefing the applicant to fly the precision approach (ILS) also as a procedural approach but with the moving map display inhibited. At the time of drafting this document, a GNSS approach that provides scaled lateral and vertical guidance (i.e. LPV approach) is not currently accepted as a precision approach and will not substitute for the ILS approach. Similarly, a GNSS approach that provides vertical guidance (e.g. LNAV+V) will not be accepted for the purposes of assessing Section 5, the non-precision approach unless the vertical guidance is inhibited.
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