Flying a Cirrus SR22T in to Gloucester Airport UK on a bumpy day. Setting up RNP Instrument Approach and confirming ATIS and the autopilot performs correctly.
Beautiful and educational video albeit a bit bumpy and without seeing the landing. The RNP process so well illustrated in the Perspective avionics. Thank you !
l like watching your videos. Quick geeky question. Since you're flying an N number plane, is there a feature where you can set the altimeter from inches to HP? or did you need maintenance to do that?
Thanks for sharing. Something I noted; the published minima is LNAV only and not LNAV/VNAV yet you used approach mode and descended using GP. The aircraft will fly the approach because it can calculate a geometric profile from the FAF to the Runway, however, it’s worth noting that the procedure designer did not calculate or validate a vertical profile, hence the minima is published as LNAV only I.e.it is a 2D approach and not a 3D approach and, as far as I am aware, the vertical profile should be managed by the pilot (using VS or FPA) and not the avionics.
Hi David, Thanks for the comment. The approach isn’t an LNAV/VNAV it is an LNAV. The avionics which have the ability to generate a pre coded GP creat an LNAV+V approach. So it is a 3D approach, but not a precision approach. There is nothing to say that you can’t let the autopilot follow the GP, which in effect is a FPA. If the avionics were not SBAS capable then it would be a 2D approach without a GP. In this case you would need to us VS at the FAF to manage you descent. Granted, maybe I should emphasise the need to cross check the altitudes with distances while the aircraft follows the generated GP as if it wasn’t there. However there is no need not to let the avionics follow the GP. Because they are very good at doing that. Thanks again for the input.
@@johnpage8364 Hi John. Thanks for your response. I’m always interested to see how others interpret, either the approach chart or their avionics capabilities, or both. I’ve always been interested in how instrument procedures are designed. I must admit, after reading through Document 8168 of ICAO PANS-OPS more than once, I still can’t find a definite statement about how pilots should fly certain RNP/GNSS approaches. I only saw, very briefly, that the approach that you filmed into Gloucester, had a charted minima box stating LNAV only. What this means (to me) is that the person(s) who designed this procedure, based the OCA(H) for this approach on LNAV functionality only and did not consider APV/Baro-VNAV in this design. Needless to say, there is a long explanation about this, but I don’t want this to seem like a seminar, rather a dialogue between us. I do agree with your comment that states that following the (V)GP is, in effect like following a FPA, which makes sense as this is an angle calculated by the on-board avionics. Unfortunately, the starting and end points of this calculation would not necessarily be the same had it been calculated using APV/Baro-VNAV principles. Also, SBAS, whilst providing your GNSS receiver with much higher integrity and accuracy, doesn’t do anything for you on this approach as this is not an LPV approach. Thanks for your video again.
@@davedebz Hi David, This video is less about the actual regulations and more about the ability of the avionics and the reality of what actual pilot do rather than what the regulations say you are suppose to do. Yes I know that the SBAS is not required to fly an LNAV+V, however unless the system is SBAS capable it won’t have the LNAV+V ability. Take a GNS430 and a GNS430W, one will do it and the other won’t. So you are telling me that with a GP on the PFD, even if it’s a LNAV+V, you wouldn’t use one of the most advanced GA autopilots to follow it, you would select VS and come down at a VS adjusting as you went? I discussed this with 2 CAA examiners, they both said, of course you’d follow it. None of the approach plates will have LNAV+V minima. As this is a function of the Avionics ability to generate the +V. They all have LNAV minimum written as if you didn’t have an SBAS capable system then pilot would potentially think that their aircraft can do it when it can’t. I’ve seen it many many times. I know the document with all the definitions etc. Yes, it’s an interesting read. This is Reality over Regulations. Regards
@@davedebz- I have flown this approach many times. It is absolutely fine to use GP mode on the G1000. It's there as a convenience/capability of the avionics. It's simply that the approach is LNAV only and therefore non-precision, as John said. Why would anyone choose to employ lower accuracy by manually trying to vertically track the computed GP, using VS mode? This is a case of the technology being there to add to safety factors. Approach status does not mandate how the pilot uses his/her aircraft to *execute* that approach. Again, APR/GP mode will afford the pilot with greater accuracy for the vertical aspect of this non-precision approach. This is no different to someone flying a fully visual approach into an airport, but choosing to have the ILS tuned and having the AP engaged on LOC and GS. By your thinking, this would not be permitted but it's perfectly legal and widely practiced.
@@davedebz- I'd sooner fly with a pilot that is taking advantage of the additional safety offered by a computed GP, rather than someone twiddling vertical speed knobs to try to stay on the profile. Why on Earth would he not be permitted to use a function of the G1000 that is designed exactly for this purpose? If the approach were annunciated as "LNAV/VNAV" this would be a precision approach. For N-P approaches like this one, the G1000 computes it's own vertical path and they are annunciated as "LNAV+V". This is telling the pilot that the LNAV component is the actual (non-precision) approach, and the "V" - not VNAV - is guidance only. Are you a pilot? Genuine question as I think 100% of pilots would understand that what was executed in this video was (a) legal and (b) best practice.
