Hi There

Just confused about alternative aerodromes under AIP ENR 1.1 (58.3.1) as it relates to Private and Charter only. If the Private plane has a 146(a) approved GPS, does a GPS approach count as an instrument approach and therefore an alternate is not required?

It says
58.3.1
A flight which is planned to be conducted under the IFR on the last route segment to its destination must provide for a suitable alternate aerodrome, unless:

for Aerial Work and Private operations
:
the destination is served by a radio navigation aid for which an
instrument approach procedure has been prescribed and the
aircraft is fitted with the radio navigation system capable of
using the aid.

Hi Anton,

Yes, an RNAV approach is considered an instrument approach. Therefore, if you have a TSO 146 GNSS unit in the aircraft, there is an RNAV approach for your destination, and you are current on RNAV/GNSS approaches, you will not need an alternate based on aids.

You may still need an alternate based on the other criteria though as covered by the mnemonic "Alternates Could Very Well Prove Life Savers" (Aids, Cloud, Visibility, Wind, Prob/Prov, Lights, Storms).

An interesting side note, by the way. The TSO 129's now are considered to satisfy the Aids requirement for RNAV/GNSS approaches but there is a special condition on them if you need an alternate for some other reason.

For example, if you use TSO 129 unit(s) and you are flying to an aerodrome that only has an RNAV/GNSS approach defined, you can continue without an alternate. However, if for example, the weather conditions or lighting dictate the need for an alternate, then you need to navigate to the alternate via ground-based aids, the alternate itself must be serviced by a ground-based aid and have a suitable approach based on that aid, or be in VMC. You are not allowed to use the TSO 129 to navigate to or to execute the approach at your alternate. Kind of weird, but that's how it reads in AIP GEN 1.5 2.1 and AIP ENR 3.3 Table in 2.1.

Cheers,

Rich

Many thanks Rich, really appreciate you taking the time to respond so comprehensively

Anton

Rich, just one final point of clarification. If I need to have an alternate (planned) and the weather at that alternate is in VMC, then is it ok to use a 129 to get you to that alternate??, if there are no other ground aids at the alternate. By VMC I am assuming LSALT+500 + 8km VIZ, and then VMC below LSALT.

Thanks

This exact question was on my IREX exam.

You can use the TSO 129 unit for track guidance but you cannot use for instrument approach - must use ground based aid - VOR or NDB at alternate destination
- see CAO 20.18 9D.10 (note 1)
unless
For aerodromes without an instrument approach procedure, the alternate minima Is the lowest safe altitude for the final route segment plus 500ft and a visibility of 8 km
- see AIP 1.1 - 59.2.12 (c)

cheers
R