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RMC
31st Mar 2019, 21:02
As a foreign operator fairly new to the USA can someone enlighten me as to whether the 50’ for a CDFA approach needs to be added to the TERPS minima for 22L of 440’ . We don’t add for RNP approaches to LNAV / VNAV minima but do add 50’ if flying to LNAV minima...neither of these appear on the associated US plates?

hans brinker
31st Mar 2019, 21:30
As a foreign operator fairly new to the USA can someone enlighten me as to whether the 50’ for a CDFA approach needs to be added to the TERPS minima for 22L of 440’ . We don’t add for RNP approaches to LNAV / VNAV minima but do add 50’ if flying to LNAV minima...neither of these appear on the associated US plates?

Short answer:
MDA/H add 50.
DA/H don't add.

Long answer:
If the minimum is a "decision" altitude you don't add the 50'. If the minimum is a "descend" altitude, but you fly using CDFA, you add the 50'. This is because while you decide to go missed on an ILS or CDFA you are still descending, while if you are level at the MDA you are not.

Don't have the plate, but hope this helps.

MarkerInbound
31st Mar 2019, 23:30
As Hans said, if it says DH treat it like an ILS or CDFA , otherwise it's a MDA and add 50 feet. It's actually a bit more complicated but that may be airline specific. In my airline's authorizations from the FAA we are allowed to treat the MDA for an ILS approach with the GS inop as a DH. Or if there is a note on the approach plate that authorized operators can use the MDA as a DH. I spent 5 minutes looking at a lot of the larger airports in the USA. I was (1) surprised how few non RNAV non precision approaches are left in service and (2) could not find any with the ball note.

I remember from years past we were also authorized to treat the MDA as a DH if the runway had a PAPI/VASI or if the runway had a precision approach even if we were not flying that approach. Those authorizations have gone away.

Smythe
1st Apr 2019, 00:20
whether the 50’ for a CDFA approach

The 50' is a minimum (for both MDA AND DA/H). Most find they need to add more than a 50' momentary descent to avoid busting the surface.

RMC
1st Apr 2019, 11:11
So TERPS is no different to EU LAND we treat these approaches as CDFA to plate LNAV minima and add 50’ to MDA minima for TERPS MDA of 440 also becomes 490’. Thanks