Equipment & installation requirements

Performance standards

The performance requirements for ADS-B OUT systems are set for the data transmitted by the on-board ADS-B OUT system. The standards ensure that the ADS-B OUT data transmitted by aircraft can be used by the ATS.

The performance standards for ADS-B OUT systems are:

TSO-C166

Please note TSO 166 can only be used for existing installations.
Must provide a NUCp of 4 or greater

TSO-C166a and TSO-C166b

NACp figure must be 5 or greater

NACv figure must be 1 or greater

SDA must be 2 or greater

For TSO-C166a, the SIL must be 2 or greater

For TSO-C166b, the SIL must be 3 or greater

• Any changes in the NACp, NACv, SDA, and SIL must be broadcast within 10 seconds
• Changes in the NIC must be broadcast within 12 seconds
• ADS-B OUT transponders must transmit updates at least once a second

Please note: New installations must meet TSO-C166b requirements. However, if you have an existing installation, it can meet TSO-C166 and TSO- C166a requirements.

Low power ADS-B transponders (LPAT) and Traffic Awareness Beacon System (TABS)

Automatic Dependent Surveillance – Broadcast (ADS-B) Trials Outcomes

In early 2017, the New Southern Sky (NSS) programme contracted BECA to conduct a Feasibility Study to determine the suitability of ADS-B Transponder and GNSS position source equipment that were not certified as per the applicable TSOs listed in NTC91.258. As part of this task it was decided that candidate low power ADS-B transponder (LPAT) options and Traffic Awareness Beacon System (TABS) options would also be examined. Primary drivers for this study included the cost and the size and weight of ADS-B equipment. 

This Feasibility Study was completed and BECA provided a report dated 29 June 2017. The report recommended a plan to test various combinations of non-TSO, LPAT and TABS equipment. The initial plan was as follows;

1. Desktop Specifications Testing
2. Benchtop Test of candidate combinations
3. ‘Real-world’ trials of candidate combinations that had been recommended at Stage 2. 

Stage 1 of the proposal was completed towards the end of 2018, and a proposal to bench test 10 combinations of transponders and GNSS position source equipment was provided in February 2019.

Following this proposal, planned changes to AC43-14 were advised. Whilst these changes to the AC do not include non-TSO devices, they included expanding the AC to include not only ‘all-in-one’ ADS-B equipment, but also to allow some TSO component/combination options. This increased the practical options available (potentially decreasing total upgrade costs), and also reaffirmed CAA messaging that non-TSO’d equipment would not be considered.

Furthermore, it was also confirmed technically with Airways that equipment with a power output of below 75 watts would not be acceptable in the New Zealand surveillance system. It was therefore concluded that further investigation into LPAT options would not be a valid use of resources.  

A decision was made in June 2019 to suspend further investigation due to;

• The high cost of continuing to investigate non-TSO options against the expected benefits;
• LPAT options being unsuitable for the New Zealand Surveillance System due to the power output being below 70 watts, while the system is designed on a minimum of 75 watts, and;
• TABS options being unsuitable for the New Zealand surveillance system due to them being certified to TSO-C199 which is not approved in the CAA Notice of Requirements, and specifically designed for awareness purposes as opposed to being for surveillance purposes.

Furthermore, with the grant announcement pending, it was noted that the perception of cost advantage gained through acquiring non-TSO’d equipment, might not remain valid. The recent announcement of the ADS-B grant to assist operators with the cost of equipping ADS-B has significantly reduced any cost driver for this activity. 

In the background, the unanticipated departure of key project personnel in mid-2019 delayed project closure and the sharing of results. Following the very recent recruitment of a new NSS ADS-B project lead we are now able to share information from this activity, and the NSS team will be actively engaging with all in the sector to clarify messaging in the lead up to the proposed mandate of 31 December 2021. 

For further information regarding ADS-B options please contact an avionics workshop (a list of workshops can be found below), or for any technical queries you can contact the Airworthiness team at the CAA at airworthiness@caa.govt.nz.