Explanatory Statement
Civil Aviation Regulations 1988
Exemption — carriage and use of automatic dependent surveillance – broadcast equipment
Legislation
Section 98 of the Civil Aviation Act 1988 (the Act) empowers the Governor-General to make regulations for the Act and the safety of air navigation.
Under subregulation 207 (2) of the Civil Aviation Regulations 1988 (CAR 1988), a person must not use an Australian aircraft in a class of operation if the aircraft is not fitted with the instruments and equipment approved and directed by CASA.
Under subregulation 207 (3) of CAR 1988, where CASA approves or directs that an instrument or item of equipment be fitted or carried on an aircraft, a person must fit, carry or use the instrument or item of equipment on the aircraft only in accordance with the directions of CASA.
Under subregulation 308 (1) of CAR 1988, CASA may, in relation to a particular aircraft, or a specified type or category of aircraft, exempt the aircraft, or persons in, on or otherwise associated with the operation of the aircraft, from compliance with specified provisions of CAR 1988.
Under subregulation 308 (3) of CAR 1988, CASA must first take into account any relevant considerations relating to the interests of safety.
Automatic dependent surveillance — broadcast (ADS-B)
For subregulation 207 (2) of CAR 1988, CASA made Civil Aviation Order 20.18 (CAO 20.18) setting out approval and directions for aircraft instruments and equipment to meet basic operational requirements.
On 6 June 2007, CASA made Civil Aviation Order 20.18 Amendment Order (No. 1) 2007 (the CAO Amendment) to insert a new subsection 9B into CAO 20.18.
Under new paragraph 9B.2 of CAO 20.18, ADS-B transmitting equipment carried by an Australian aircraft for operational use in any class of operation in Australia must comply with an approved equipment configuration set out in new Appendix XI, or as approved in writing by CASA.
Under new paragraph 9B.3, ADS-B transmitting equipment that does not comply must be deactivated before flight in Australia. Under new paragraph 9B.4 of CAO 20.18, ADS-B transmitting equipment must transmit particular flight identification particulars.
Appendix XI sets out the standards that ADS-B transmitting equipment must meet if it is to comply with the requirements under the CAO Amendment. Those standards are in conformity with the relevant ICAO standards and recommended practices.
Background to the exemption
Qantas Airways Limited (the operator) applied for a 12 month exemption from subsection 9B of CAO 20.18 because, due to a recently identified software design problem, its Boeing 747-400 fleet of aircraft could not meet the requirements of the subsection.
Over the last few years these aircraft have been modified to meet European (EuroControl) Elementary and Enhanced Surveillance mandates. The modifications also enabled ADS‑B Out functionality.
Subsequently, it was discovered that, during flight, the “Aircraft Identification” downlink parameter, otherwise known as “Flight ID” was periodically corrupted. This was due to a design flaw in the operating software of the relevant transponder. The problem is not restricted to Qantas aircraft but to many other B747-400s worldwide. Thus, although for the greater part of any flight, the aircraft transmits the correct flight identification data, for certain aircraft input database configurations, the transmission is corrupted by a design flaw in the transponder’s software.
Under paragraphs 9B.2 and 9B.4 of CAO 20.18, ADS-B transmitting equipment must comply with the approved equipment configuration and transmit exact flight identification particulars. Thus, the design flaw means that the operator’s Boeing 747-400 fleet is non-compliant with paragraphs 9B.2 and 9B.4 of CAO 20.18 even though, for the greater part of any flight, the aircraft transmits the correct flight identification. Under paragraph 9B.3, ADS-B transmitting equipment that does not comply must be deactivated before flight. This would be the case unless the transponder is appropriately modified or replaced.
The Boeing Aircraft Corporation is certifying a new transponder and following that the operator proposes a managed rectification process, first to obtain CASA approval for, and then to install, some 80 of the new transponders on some 30 aircraft over a period of 12 months. Application for approval under subsection 9B of CAO 20.18 will be required for use of the new transponder in combination with the aircraft’s existing global positioning systems receivers.
Safety issues
Airservices Australia Aeronautical Information Package (AIP), dated 7th June 2007, General (GEN) 1.5 Aircraft Instruments, Equipment and Flight Documents, paragraph 11, ADS-B Operations, states the following:
“To receive ADS-B derived ATS surveillance in Australian airspace, aircraft operators must make application to Airservices Australia. Only aircraft meeting the criteria for ADS-B operations in Australia shall be eligible to receive ADS-B derived services. ADS‑B data from ineligible aircraft will not be displayed to ATC.”
Qantas has not applied to Airservices Australia for ADS-B derived surveillance services for the Qantas B747-400 fleet.
The fact that an aircraft will not receive ADS-B derived services does not of itself raise any safety concern. Subsection 9B of CAO 20.18 does not make use of ADS-B compulsory. To ensure that there is no interference with the operations of those aircraft that are compliant, subsection 9B of CAO 20.18 requires non-compliant ADS-B equipment to be deactivated. Activated, but non-compliant ADS-B equipment can cause confusion in transmissions.
However, in the case of the operator, to deactivate the ADS-B equipment would also deactivate the transponder which, although causing intermittent corruption of flight identification data transmission, is otherwise essential for the safe operation of the aircraft. Hence, the effect of the exemption is that the operator need not deactivate its non-complying ADS-B equipment.
CASA is satisfied that this activation does not give rise to any safety concern in respect of either the operator’s Boeing 747-400 fleet or other aircraft carrying compliant ADS-B equipment.
Since the Qantas B747-400 aircraft are not currently approved by Airservices Australia (AA) for ADS-B operations, the ADS-B data from these aircraft will not be displayed to air traffic control. It will not cause confusion in transmissions and the safety of aircraft operations is not affected. Similar arrangements are in place for this Boeing 747-400 anomaly in the European Aviation Safety Authority.
The exemption will not result in a lowering of pre-existing safety standards or levels. However, during the period of the exemption, the subject aircraft will not be eligible to receive, or be capable of receiving, ADS-B related services from AA.
Legislative Instruments Act
Under subparagraph 6 (d) (i) of the Legislative Instruments Act 2003 (the LIA), an instrument is a legislative instrument for section 5 of the LIA if it is declared to be a disallowable instrument under legislation in force before the commencement of the LIA. Subregulation 308 (4) of CAR 1988 declares an exemption to be a disallowable instrument. The instrument is, therefore, a legislative instrument and is subject to tabling and disallowance in the Parliament under sections 38 and 42 of the LIA.
Consultation under section 17 of the LIA has not been undertaken because the instrument is for a specific operator.
The instrument comes into effect immediately after the registration of Civil Aviation Order 20.18 Amendment Order (No. 1) 2007.
The exemption has been made by the Deputy Chief Executive Officer, Strategy and Support, a delegate of CASA, in accordance with subregulation 7 (1) of CAR 1988.
[Exemption number CASA EX27/07]