Recommendation R19970151

Recommendation issued to: Civil Aviation Safety Authority

Recommendation details
Output No: R19970151
Date issued: 01 October 1997
Safety action status:


Comprehensive systems safety analysis of the simultaneous opposite direction parallel runway operations (SODPROPS).


Occurrence 9700052

Simultaneous opposite direction parallel runway operations (SODPROPS) were introduced at Sydney (Kingsford-Smith) Airport, whereby arriving aircraft approach and land on one runway concurrently with aircraft departures from the parallel runway, in the opposite direction.

In this occurrence, an A320 aircraft was to depart from runway 16 Left and the A320 crew were assigned a radar departure with an initial left turn onto 115 degrees. The crew mistakenly dialled 155 degrees into their flight management system (FMS), despite correctly acknowledging the assigned heading of 115 degrees.

There was an aircraft approaching runway 34 Left, the reciprocal parallel runway, under the SODPROPS procedure.

After takeoff, when the A320 crew selected the heading mode on the FMS, they realised that they had set the incorrect heading. They continued on the runway heading until the correct heading could be confirmed. The Tower controller was not able to instruct the crew to turn left as they had already transferred to the Departures South (DEPS) frequency.

The Departures South controller instructed the A320 crew to turn left onto 115 degrees and the aircraft did not breach the separation standard for the approach in this instance.

The investigation found no record of any significant analysis of the risks associated with the development and adoption of SODPROPS for Australian use.


The safety implications of SODPROPS were not adequately addressed prior to the introduction of the procedure at Sydney Airport.


Investigation of the occurrence found that the Civil Aviation Safety Authority (CASA) adapted a USA Federal Aviation Administration (FAA) air traffic control spacing and sequencing standard (FAA 7110.65J) and incorporated it into the CASA Manual of Operational Standards part 3, para. 5.9 "Simultaneous Opposite Direction Operations". There was no record that CASA had conducted any significant analysis of the risks associated with the SODPROPS procedure

Airservices Australia held an industry seminar in September 1996 to discuss proposed Sydney traffic management procedures including the limited use of SODPROPS. At this seminar several participants questioned the extent of risk analysis that had been conducted to ensure that SODPROPS provided adequate levels of safety during all operations. The risk analysis provided to the industry indicated that a form of quantitative modelling had been conducted but that the analysis had been performed on a narrow set of data. The assumptions for the modelling were not analysed and the model itself was not validated as required in the Legislative Instrument Proposal (LIP) for the safety regulation of Airservices Australia. The analysis considered localiser track keeping and departure procedure compliance. The available evidence indicates that the analysis was not comprehensive.

The Bureau investigated a serious occurrence at Sydney in 1991 involving a near collision following the introduction of Simultaneous Runway Operations (SIMOPS). One of the safety recommendations resulting from that investigation was that the then Civil Aviation Authority "ensure that, prior to the implementation of any significant change in operational procedures or regulations, a comprehensive systems safety analysis is carried out." Similarly, section 6.3 of the LIP specifically details the manner in which Airservices Australia is required to manage changes to systems, equipment or procedures to ensure that unacceptable hazards are eliminated by the time that the change is completed. There was no evidence that these requirements were met.

CASA advised Airservices Australia that the standard governing the use of SODPROPS was available for use without impediments to its application, providing that the risks associated with the changes were analysed to ensure that unacceptable hazards were eliminated before the change was completed. Airservices Australia based some of the safety analysis of SODPROPS on the use of similar overseas procedures at international airports. Investigation by the Bureau of overseas operations found that this premise was not substantiated. Some minor examples of international parallel opposite direction operations were found but were not regarded as sufficiently similar to the Sydney operation to be used to support Airservices Australia's risk analysis.

Although the use of SODPROPS was restricted to a limited time during the day, there is now the possibility of extending the hours of operation at KSA. As the SODPROPS procedure was introduced with an inadequate analysis of the risks it is imperative that a comprehensive systems safety analysis be carried out as soon as practicable.

Output text

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority review the Operational Standard "Simultaneous Opposite Direction Operations" to ensure that it provides an acceptable level of safety.

The Bureau has also made the following recommendation (R970150) to Airservices Australia:

"The Bureau of Air Safety Investigation recommends that Airservices Australia conduct a comprehensive systems safety analysis of simultaneous opposite direction parallel runway operations (SODPROPS)."

Initial response
Date issued: 27 November 1997
Response from: Civil Aviation Safety Authority
Action status: Closed - Accepted
Response text:

CASA has reviewed the Operational Standard "Simultaneous Opposite Direction Operations" as you have recommended.

Following Occurrence 9700052 on 5 January 1997 the instructions in AIP OPS paragraph 19.4 were changed by NOTAM to require pilots to remain on Tower frequency until instructed to change, thus enabling Tower to correct the kind of confusion evident during the occurrence. The amendment will be correctly inserted into the AIP OPS text by AIP Amendment List 20, effective 4 December 1997.

Given the change to procedures our conclusion is that the standard expressed in the CASA Manual of Operational Standards (MOS) Part 3 Chapter 5.9 is adequate.

The MOS standard will be further reviewed in the light of any study which may be undertaken by Airservices in response to your recommendation R970150.

After dispatching a copy of the [name supplied] report to CASA the following response was received on 28 Aug 1998:

The letter requests a formal CASA response to the recommendations in a report attributed to [name supplied]. It cites the CASA/BASI MOU as the basis for advice of actions CASA intends to take in response to those recommendations.

It is our belief that this request is not consistent with the MOU between our two organisations. That MOU lays out a basis for CASA to respond to safety deficiencies identified by BASI and recommendations made by BASI to rectify those deficiencies. It does not require CASA to address recommendations made by a third party.

It was our understanding that BASI would be forwarding a draft investigation report to CASA for comment. That report would be along the lines of the outline we had informally discussed early in July, and would at your discretion incorporate such findings of the Gleave report as you saw fit. We would of course be pleased to provide comment on such a report and indicate actions taken or planned to address any recommendations the Bureau may choose to make. We are, as you know, already addressing a number of the issues discussed at our meeting in July. If you have any questions on this issue please don't hesitate to call.

Last update 01 April 2011