Hi Guys,

The AIP's requirments for aids is layed out in AIP GEN 1.5 2. RPT & CHTR req 1GNSS 129 or later + 1ADF / 1VOR or 2GNSS 145/146
PVT & AWK is the same except only 1 GNSS is req if 145/156 (not 2)

Everyone is familiar with this.

My question arises from your book, where is states under the PBN section that ADS-B is a requirement for ALL IFR from Feb 2017. I only have the online e-text, it is page 108/109. Considering GNSS TSO129 does not support ADS-B, how can any aircraft fitted with 1GNSS 129 or later + 1ADF / 1VOR (RPT,CHTR,PVT,AWK req) be allowed to take off?

CAO 20.18 section 9D.3 (etc) has new standards for aircraft fitted with GNSS (from my understanding all aircraft manufactured after Feb 2016 or GNSS installed after Feb 2016 are not permitted to have TSO129 equipment, it must be 145a/146a - I assume to support the ADS-B requirement)

SO, exam wise, have you got any ideas what I should base my answers from? If a question arose about the nav / alternate requirements for a PVT flight (for example) fitted with a TSO129 + ADF/VOR then technically it can't depart IFR without an ADS-B supported GNSS (which it does not have). Unless the date of manufacture / GNSS instillation is detailed in the question.

Or does the ADS-B functionality come solely from the Mode S Transponder and I'm reading the book wrong where it says 'ADS-B requires a TSO145a/146a or 196 GNSS'

Also, any idea why the AIP makes no mention of the Feb 2016 requirements that are mentioned in the CAOs? Which one should I trust the most?

Cheers,
Scruffy

It would appear that the 1 x 129 GPS plus 1 x ADF or 1 x VOR was meant to be a transitional requirement to allow time for operators to update as necessary. However, the exam aeroplane (VH-OZY), is equipped with two TSO 146 RNAV/GNSS receivers so that solves that problem. The exam question will have to specify VH-OZY or any other specific aeroplane appropriately equipped after the change-over date. It will be up to the examiner to ensure that the question is worded accordingly.

Thanks Bob, I am still a little confused as to where exactly the ADS-B comes from. The transponder OR the gnss unit. As I have read multiple things that say ADS-B is a requirement of TSO145/146 and also that Mode S Transponders have ADSB.

Any clarification would be greatly appreciated

ADSB gets positional (position altitude and velocity) information from the GPS and transmits it automatically via the transponder Mode S. That's called ADSB (out). ADSB (in) allows the aircraft to receive those transmission to provide the pilot with information on the position of other aircraft.

OK, so if your GNSS (GPS) unit wasn't working - but you had a different aid (VOR eg) and a Mode S Transponder. Are you still able to fly IFR? Are you still able to output an ADS-B signal?

ADSB requires GNSS and mode S transponder. The VOR signal is not compatible with the transponder and, even if it was it would give no useful information as to the aircraft's position. A VOR must be interpreted by the pilot and gives the aircraft's position relative to the VOR's location, whereas GNSS gives the actual aircraft's position position as lat and long coordinates. The GNSS's solution for the aircraft's position is required for the transponder to broadcast the aircraft's current current altitude, position, and velocity along with other data

OK so it would be fair to say that if you had a TSO129a GNSS unit as the only GNSS unit in your aircraft - even if it was installed pre 06/FEB/16 you are unable to fly IFR because the unit is not ADS-B compatible with the transponder?

P.S. Thank you for continuing to reply to this thread. It is really helpful with my understanding.

That's the way I would interpret it.
See also
www.airservicesaustralia.com/projects/ad...-mandates-2014-2017/

Thanks for the link - the way I read the mandate is that continued operation without an ADB-B compliant GNSS unit is only available to IFR PVT flights in only some airspace and only until 2020.

So why then does the AIP have a whole table dedicated to flights using ground based aids only (AIP GEN 1.5 2.2 (Radio Nav Systems) if operations without a suitable GNSS unit is compulsory? and by suitable I mean ADSB compliant (145/146/196).

2.1 of the AIP says RPT & CHTR can also have a 129 plus an adf or vor, but we just discovered that having a 129 does not meet the requirements of adsb.

Is the AIP out of date with regards to nav aid requirements? Or am I missing something?