Boeing: Flying LNAV/VNAV without VNAV
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Join Date: Nov 2008
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Dear Bracebrace,
thank you for your input. You may be very correct, but I can not find any regulations that supports your statement.
Can you please help me find it?
I found this in PANS-OPS 8168, and I'm getting more confident that this is the reason why we cant fly LNAV/VNAV without FD or AP in the 744:
thank you for your input. You may be very correct, but I can not find any regulations that supports your statement.
Can you please help me find it?
I found this in PANS-OPS 8168, and I'm getting more confident that this is the reason why we cant fly LNAV/VNAV without FD or AP in the 744:
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Banana Joe
Haha are we really seen like that
My comment was for the ILS of course. For RNP approaches, any type except RNP AR which required more automation, our procedures state the following :
at least 1 F/D is required from FAF to MAPt
- When using VNAV minimums, IAN or LNAV/.VNAV is required.
- When using LNAV minimums, IAN, LNAV/VNAV, or LNAV/V/S is required.
Obviously when suitable visual reference is established nothing is required anymore.
Haha are we really seen like that
My comment was for the ILS of course. For RNP approaches, any type except RNP AR which required more automation, our procedures state the following :
at least 1 F/D is required from FAF to MAPt
- When using VNAV minimums, IAN or LNAV/.VNAV is required.
- When using LNAV minimums, IAN, LNAV/VNAV, or LNAV/V/S is required.
Obviously when suitable visual reference is established nothing is required anymore.
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Interesting, so at least one FD is still required? From the FCOM of a german airline:
IAN may be used with the flight director, single autopilot, or flown with raw data. The procedure turn, initial approach, and final approach are similar to the ILS.
Which most of us used to fly most IAN approaches in "raw data" without any flight director help. Same as we did for most ILS and GLS approaches. When we phased out the 737 we sorely missed that feature on the A320, which theoretically could have it with FLS, but i have not seen a FLS equipped A320 in the wild despite flying it for numerous operators, unlike IAN which has been standard for since 2005 or so, same as GLS.
IAN may be used with the flight director, single autopilot, or flown with raw data. The procedure turn, initial approach, and final approach are similar to the ILS.
Which most of us used to fly most IAN approaches in "raw data" without any flight director help. Same as we did for most ILS and GLS approaches. When we phased out the 737 we sorely missed that feature on the A320, which theoretically could have it with FLS, but i have not seen a FLS equipped A320 in the wild despite flying it for numerous operators, unlike IAN which has been standard for since 2005 or so, same as GLS.
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Dear all.
Here's a scenario from a recent simulator exercise (a bit simplified).
On the MCP panel, both Vertical Navigation (VNAV) Switch and Approach (APP) Switch are INOP. Everything else is operational.
Can an ILS be flown to ILS DA(H) and/or can a LNAV/VNAV be flown to LNAV/VNAV DA(H), using the remaining operational functions of the autopilot (e.g. LOC+V/S or LNAV+V/S?
Here's a scenario from a recent simulator exercise (a bit simplified).
On the MCP panel, both Vertical Navigation (VNAV) Switch and Approach (APP) Switch are INOP. Everything else is operational.
Can an ILS be flown to ILS DA(H) and/or can a LNAV/VNAV be flown to LNAV/VNAV DA(H), using the remaining operational functions of the autopilot (e.g. LOC+V/S or LNAV+V/S?
2️⃣ Short Answer - NO can’t use LNAV/VNAN (DA)
You May want to read FAA AC 20-105A Appendix B for more info.
In principle, RNP APCH Approaches with LNAV/VNAV Minima are 3D Approaches. Once VNAV is lost, any other backup (A/p F/d) mode makes it a 2D Approach. You might want ask about FPA in that case, even use of FPA is considered 2D (refer DOC 8168 6th Edition 2.3.3)
The word ‘DA’ added to LNAV/VNAV minima mandates the Approach be carried out as a 3D operation. (refer DOC 8168 6th Edition 2.3.4)
(refer DOC 8168 6th Edition 2.5.5 foot note 1)
The biggest draw back is that the information on RNP APCH is scattered across many documents. If one would want to enquire if certain approaches could be carried out after certain equipment failure in their airplane it becomes difficult to determine the most legal course of action.
