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A is for Aids
Carello
Topic Author
Carello created the topic: A is for Aids
Hi
Working through the e-text IREX book I encountered Example 2 in the section "A is for Aids" - see attachment.
At the end of the exercise the following comment was made " Note that the GNSS equipment you have would satisfy the alternate requirement for navigation aids and if the weather had been above the alternate minimum, you would not have needed an alternate"
In the past RNAV(GNSS) and GPS arrivals were not available for planning purposes unless the GPS receiver was certified to TSO-145/146. For a TSO129 aircraft, this would then mean an alternate would be required for Corryong in all cases - assuming a visual approach was not possible.
So, in summary, under the new rules, an alternate for Corryong is not required if the weather was above the alternate minima but under the old rules an alternate would be require.
Can anyone explain this paradox? Are TSO 129 receivers smarter now or have the rules regarding there use simply been relaxed
Not really a paradox. The old rule was replaced by the new rule and the old rule no longer applies - happens all the time.
The exam aeroplane, VH-OZY, has been modified. It once had only one TSO 129 GPS. It now has 2 TSO 146 GPSs. Under the old rule, if you had only a TSO 129 GPS, it didn't count when considering the need for an alternate. The new rule says that you can count a TSO 129 GPS, but if you do need an alternate for any reason, the alternate you choose must have a ground based navigation aid and you must be capable of navigating to that alternate using the ground based aid.
