The Australian Transport Safety Bureau (ATSB) today published an investigation report into how a retail development was allowed to be built so close to a runway at Essendon.
The Bulla Road retail precinct–also called the Direct Factory Outlet (DFO)–came into question in 2017 after a Beech King Air crashed into the buildings on take-off from runway 17, killing all five people on board.
An ATSB investigation found that the pilot had failed to notice the rudder trim was set hard left, which robbed the aircraft of the ability to climb, but the ATSB also announced they would investigate the siting of the DFO.
Released today after more than five years, a second ATSB investigation report concludes that the DFO was built based on it not infringing the obstacle limitation surface (OLS) for runway 26, which was set at 180 m wide (90 m from the centreline) even though airport standards require the runway width to be set at 300 m wide.
According to ATSB investigators, in 2003, "a CASA officer provided EAPL with a letter stating that the transitional surface could be based off the 180 m published runway strip. EAPL prepared the major development plan for the Bulla Road Precinct on this basis."
The report noted that CASA audited the runway in 2012 and 2014, both times listing the non-compliance and requiring Essendon Airport Proprietary Limited (EAPL) to publish the width at 300 m. The ATSB could find no existing record of how the 180 m width was set in the first place.
In 2015 CASA issued instrument 153/15, which set the runway width at 300 m. This meant the DFO, which was built in 2005, infringed the OLS, but pilots were notified of the obstacle.
In 2019, EAPL re-set the width to 180 m by grandfathering the provisions allowed under the CASR Part 139 Manual of Standards, even though the genesis of the 180-m width was uncertain.
ATSB Chief Commissioner Angus Mitchell said the investigation involved a lot of analysis of airport standards and how they were applied.
“This complex investigation made nine findings pertaining to the acceptance of grandfathering in non-standard circumstances, review of safety cases, limited guidance for some safety standards, and assurance processes between federal agencies for airport planning relating to the Bulla Road Precinct,” he said
“We note that both CASA and the airport operator have maintained that there is an acceptable level of safety with the current status of the runway strip, obstacle limitation surfaces, and publication of information to pilots.
"It was not the role of the ATSB to do a separate risk assessment, but we have noted the type of risk information that should be taken into account by aerodrome operators and regulators.”
The nine findings published in the report are:
- ICAO Annex 14 and Australian standards for transitional surfaces were unclear on how they should be applied if the runway strip width was less than standard
- Since 1972, successive aerodrome operators had published a 180 m strip width for runway 08/26
- In 2005, the transitional surfaces were likely being maintained in accordance with the standards applicable at the time, which were interpreted to allow part of the transitional surface to be located along the side of the approach surface and the other part along the side of the published runway strip
- Aerodrome operators used the Australian aerodrome standards to establish the OLS. For the purpose of building control around federally leased aerodromes, the Australian Airports (Protection of Airspace) Regulations referenced the international aerodrome standards
- In 2004, the Department of Transport and Regional Services did not have an agreed assurance framework with CASA for assessing the safety information in draft major development plans
- In 2019, the grandfathering provisions of the Manual of Standards Part 139 made it uncertain how the provisions could be applied to a runway strip width that had been published as compliant with those standards
- The Manual of Standards Part 139 did not require submission of a safety case to CASA to consider for acceptance of grandfathering. However, a safety case was prepared by EAPL, completed in accordance with its safety management system
- The policy permitting grandfathering, conservative aerodrome design principles, the graded portion of the runway strip, aircraft weight limitations, and the raised landing minima were mitigating factors for maintaining the runway 08/26 strip width less than that required by aerodrome standards in 2019 and location of the associated transitional surfaces
- There was limited guidance from ICAO and CASA on risk considerations for the OLS around the runway strip protecting aircraft during the approach to land.
"This investigation highlights the complex nature of airport planning and aerodrome safeguarding with the many factors that need to be considered to ensure an acceptable level of safety,” Mitchell concluded.
“Aerodrome planning and aerodrome safeguarding can be further complicated when applying aerodrome standards with changing design criteria over a long historical period, as was the case at Essendon Fields Airport.
"It is even more challenging when there are incomplete records, limited guidance on how design criteria relate to risk, and changing interpretations of standards.”
The full report is on the ATSB website.