P2 - Damning Fragrantly Obfuscated.(DFO)..
While we all wait with bated breath for the aerodrome 'expert' at AOPA to provide comment on the Essendon Fields DFO event; there is other information of interest to consider.
It is worth downloading the PDF version of the ATSB report – HERE – it may assist in avoiding 'a rabbit hole the size of the Grand Canyon'. You can actually skip through and read the ATSB 'blue and green shaded boxes, which seem to assist in clarifying the 'other' stuff written above. Well done Hitch; it was a big job ploughing through the whole thing; seems only fair to offer the 'Hitch' opinion first; not too shabby an effort – Choc Frog...
HITCH - “The ATSB looks like it has been down a rabbit hole the size of the Grand Canyon in its efforts to find out why a DFO was built so close to a runway at Essendon. After five years of investigation and compiling a 146-page report, the ATSB has laid out all its findings, but tellingly has made no recommendations. Here's my summary as I see it. The DFO was built so close to runway 26 because CASA told them the OLS could be based on a 180-m wide runway strip, as was the width of the runway that had been published for a number of years. However, no-one can remember why the runway width was ever set at 180 m and no records can be found. Had the required 300-m width been enforced at that time, the DFO would have had to have been set back further, unless an exemption was granted. What all this tells me is that somehow, some way, the system failed to raise a red flag at a crucial time in the approval process. The runway width is still set at 180 m despite it being less than standards required because of the grandfathering provisions of Part 139. It's important to note that this grandfathering happened during the course of this investigation, and now shores up the legitimacy of the runway width. Despite sifting through the minutiae of Australian and international airport standards, the ATSB has been unable to flag any changes that could prevent such a thing happening again. And you can be assured that sometime in the future, one of the operators of the Commonwealth leased airports will want to build something closer to a runway than the standards allow. At that time, we will see if any lessons have been learned from the Essendon DFO.”
Of course, for those who prefer the 'nut-shell' version, ATSB shaded boxes :-
“In response to a previous draft version of this investigation report, CASA indicated that ‘Aircraft operators and pilots need to assess the suitability of the aerodrome for their intended operations based on published information’. This was consistent with former regulation 92 of the Civil Aviation Regulations 1988 and currently in section 91.410 of the Civil Aviation Safety Regulations 1998, which placed the onus on pilots and aircraft operators to determine the suitability of an aerodrome or other place for take-off or landing.”
Just about sums up CASA attitude to any and all real admission of responsibility. All care but no responsibility seems to be a feature of the regulatory philosophy. The really short version of that philosophy seems to be 'you pays your money and takes your chances'. No matter; grab the PDF version, scroll through to the 'blue' shaded boxes, before reading the 'black and white' bits – interesting stuff – or not, depending on your POV....Some ATSB 'blue box' examples (below) follow my scribble:-
“In response to a previous draft version of this investigation report, CASA indicated that ‘Aircraft operators and pilots need to assess the suitability of the aerodrome for their intended operations based on published information’. This was consistent with former regulation 92 of the Civil Aviation Regulations 1988 and currently in section 91.410 of the Civil Aviation Safety Regulations 1998, which placed the onus on pilots and aircraft operators to determine the suitability of an aerodrome or other place for take-off or landing.”
“The approach and transitional surfaces worked together to provide obstacle protection to aircraft in the final stages of the approach to land and during a missed approach. The ICAO Secretariat advised that this would be achieved using their interpretation of the standard in ICAO Annex 14 with the surfaces aligned by the inner edge of the approach surface. Advice provided by CASA acknowledged the Australian standards may allow for misalignment on a case-by-case basis. However, they have also advised that the transitional surfaces and inner edge of the approach surface must be consistent with the actual (published) runway strip width.”
“The actions taken by ICAO in 2018 were changes to the dimensions in the standards. By contrast, in 2020, the ICAO Secretariat’s advice to the ATSB was about the application of the standards as they were drafted.”
“The ATSB notes that, under ICAO Annex 14 the dimensions of the inner edge of the approach surface were determined by the aerodrome reference code applied to the runway and not by the dimensions of the runway strip width. This was similarly the case in the Australian standards for the RPAs, MOS Part 139 and Part 139 MOS 2019.”
“Under the RPAs, MOS Part 139 and Part 139 MOS 2019, CASA interpreted the standard so that the lower edge of the transitional surface alongside the runway strip moved inwards when the strip width was reduced to less than that required by the standards. The part of the transitional surface alongside the approach surface would no longer be aligned if the dimension of the inner edge of the approach surface remained unchanged. CASA noted there was no explicit requirement in the Australian standards for alignment.”
“ICAO’s interpretation of the ICAO Annex 14 standard would ensure the transitional surface did not move when the runway strip width was reduced. However, it was observed that this would create an unexplained space between the side of the published runway strip with its reduced dimensions and the lower edge of the transitional surface.”
“Neither ICAO nor CASA published guidance in support of their stated expectations for interpreting the standards. However, ICAO noted that there was an opportunity to consider guidance with work on reviewing the OLS.”
“Changes to the alignment of the transitional surface for runway 26 with variations in the published runway strip width and inner edge of the approach surface are discussed in subsequent chapters. Application of both the Australian standards and the international standards are also considered.”
“The basic ILS surfaces were based on the standard dimensions of the runway strip and the OLS in ICAO Annex 14. They were not determined by the dimensions in the Australian aerodrome standards or what an aerodrome operator published as the actual runway strip and OLS. Therefore, changes to the runway strip and/or OLS could result in a gap between the transitional surfaces components of the PANS-OPS basic ILS surfaces and the OLS surfaces. There was therefore the potential for penetrations of the transitional surface component of the PANS-OPS basic ILS surfaces to not be identified due to the obstacle monitoring requirements in the Australian aerodrome standards only applying to the OLS established in accordance with those standards.”
“There were differing conditions attached to the varying means for accepting an aerodrome operator’s non-compliance with a standard. All the means for obtaining acceptance, apart from grandfathering, required consideration of the safety effect by the regulator. Grandfathering was permitted by the standards without a formal requirement to seek approval from the regulator with consideration of the safety effect.”
“The wording of the International Civil Aviation Organisation (ICAO) Annex 14 and the
Australian standards for the transitional surfaces was not clear on how they should be applied when the runway strip width (as permitted) was less than the standard. Both standards worked in practice where the strip width and associated OLS met the standard dimensions. However, the wording of the respective standards was open to different interpretations for addressing the misalignment between the runway strip width and the inner edge of the approach surface. Neither ICAO or the Civil Aviation Safety Authority provided guidance in support of their respective interpretations.”
“With a runway 08/26 strip width of 180 m and approach inner edge of 300 m (for runway 26), as detailed in the OLS diagram and per the CASA 2 October 2003 advice, the buildings associated with the Bulla Road Precinct did not infringe the respective transitional surface. These dimensions were used for the basis of the major development plan.”
“Since 1972, successive aerodrome operators had published a 180 m strip width for runway 08/26. However, in 2005, when the Bulla Road Precinct was developed, it was unlikely that the aerodrome standards against which the strip width was based had been adequately determined to assure compliance against those standard.”
“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 alongside the approach surface and the other part alongside the published runway strip. With the different dimensions of the inner edge of the approach surface and runway strip, the transitional surfaces were misaligned.”
There are many more, mostly worth the time – and they do help clarify the bulk. IMO the only two questions which really need to be answered go begging. MTF..
Toot – toot.
While we all wait with bated breath for the aerodrome 'expert' at AOPA to provide comment on the Essendon Fields DFO event; there is other information of interest to consider.
It is worth downloading the PDF version of the ATSB report – HERE – it may assist in avoiding 'a rabbit hole the size of the Grand Canyon'. You can actually skip through and read the ATSB 'blue and green shaded boxes, which seem to assist in clarifying the 'other' stuff written above. Well done Hitch; it was a big job ploughing through the whole thing; seems only fair to offer the 'Hitch' opinion first; not too shabby an effort – Choc Frog...
HITCH - “The ATSB looks like it has been down a rabbit hole the size of the Grand Canyon in its efforts to find out why a DFO was built so close to a runway at Essendon. After five years of investigation and compiling a 146-page report, the ATSB has laid out all its findings, but tellingly has made no recommendations. Here's my summary as I see it. The DFO was built so close to runway 26 because CASA told them the OLS could be based on a 180-m wide runway strip, as was the width of the runway that had been published for a number of years. However, no-one can remember why the runway width was ever set at 180 m and no records can be found. Had the required 300-m width been enforced at that time, the DFO would have had to have been set back further, unless an exemption was granted. What all this tells me is that somehow, some way, the system failed to raise a red flag at a crucial time in the approval process. The runway width is still set at 180 m despite it being less than standards required because of the grandfathering provisions of Part 139. It's important to note that this grandfathering happened during the course of this investigation, and now shores up the legitimacy of the runway width. Despite sifting through the minutiae of Australian and international airport standards, the ATSB has been unable to flag any changes that could prevent such a thing happening again. And you can be assured that sometime in the future, one of the operators of the Commonwealth leased airports will want to build something closer to a runway than the standards allow. At that time, we will see if any lessons have been learned from the Essendon DFO.”
Of course, for those who prefer the 'nut-shell' version, ATSB shaded boxes :-
“In response to a previous draft version of this investigation report, CASA indicated that ‘Aircraft operators and pilots need to assess the suitability of the aerodrome for their intended operations based on published information’. This was consistent with former regulation 92 of the Civil Aviation Regulations 1988 and currently in section 91.410 of the Civil Aviation Safety Regulations 1998, which placed the onus on pilots and aircraft operators to determine the suitability of an aerodrome or other place for take-off or landing.”
Just about sums up CASA attitude to any and all real admission of responsibility. All care but no responsibility seems to be a feature of the regulatory philosophy. The really short version of that philosophy seems to be 'you pays your money and takes your chances'. No matter; grab the PDF version, scroll through to the 'blue' shaded boxes, before reading the 'black and white' bits – interesting stuff – or not, depending on your POV....Some ATSB 'blue box' examples (below) follow my scribble:-
“In response to a previous draft version of this investigation report, CASA indicated that ‘Aircraft operators and pilots need to assess the suitability of the aerodrome for their intended operations based on published information’. This was consistent with former regulation 92 of the Civil Aviation Regulations 1988 and currently in section 91.410 of the Civil Aviation Safety Regulations 1998, which placed the onus on pilots and aircraft operators to determine the suitability of an aerodrome or other place for take-off or landing.”
“The approach and transitional surfaces worked together to provide obstacle protection to aircraft in the final stages of the approach to land and during a missed approach. The ICAO Secretariat advised that this would be achieved using their interpretation of the standard in ICAO Annex 14 with the surfaces aligned by the inner edge of the approach surface. Advice provided by CASA acknowledged the Australian standards may allow for misalignment on a case-by-case basis. However, they have also advised that the transitional surfaces and inner edge of the approach surface must be consistent with the actual (published) runway strip width.”
“The actions taken by ICAO in 2018 were changes to the dimensions in the standards. By contrast, in 2020, the ICAO Secretariat’s advice to the ATSB was about the application of the standards as they were drafted.”
“The ATSB notes that, under ICAO Annex 14 the dimensions of the inner edge of the approach surface were determined by the aerodrome reference code applied to the runway and not by the dimensions of the runway strip width. This was similarly the case in the Australian standards for the RPAs, MOS Part 139 and Part 139 MOS 2019.”
“Under the RPAs, MOS Part 139 and Part 139 MOS 2019, CASA interpreted the standard so that the lower edge of the transitional surface alongside the runway strip moved inwards when the strip width was reduced to less than that required by the standards. The part of the transitional surface alongside the approach surface would no longer be aligned if the dimension of the inner edge of the approach surface remained unchanged. CASA noted there was no explicit requirement in the Australian standards for alignment.”
“ICAO’s interpretation of the ICAO Annex 14 standard would ensure the transitional surface did not move when the runway strip width was reduced. However, it was observed that this would create an unexplained space between the side of the published runway strip with its reduced dimensions and the lower edge of the transitional surface.”
“Neither ICAO nor CASA published guidance in support of their stated expectations for interpreting the standards. However, ICAO noted that there was an opportunity to consider guidance with work on reviewing the OLS.”
“Changes to the alignment of the transitional surface for runway 26 with variations in the published runway strip width and inner edge of the approach surface are discussed in subsequent chapters. Application of both the Australian standards and the international standards are also considered.”
“The basic ILS surfaces were based on the standard dimensions of the runway strip and the OLS in ICAO Annex 14. They were not determined by the dimensions in the Australian aerodrome standards or what an aerodrome operator published as the actual runway strip and OLS. Therefore, changes to the runway strip and/or OLS could result in a gap between the transitional surfaces components of the PANS-OPS basic ILS surfaces and the OLS surfaces. There was therefore the potential for penetrations of the transitional surface component of the PANS-OPS basic ILS surfaces to not be identified due to the obstacle monitoring requirements in the Australian aerodrome standards only applying to the OLS established in accordance with those standards.”
“There were differing conditions attached to the varying means for accepting an aerodrome operator’s non-compliance with a standard. All the means for obtaining acceptance, apart from grandfathering, required consideration of the safety effect by the regulator. Grandfathering was permitted by the standards without a formal requirement to seek approval from the regulator with consideration of the safety effect.”
“The wording of the International Civil Aviation Organisation (ICAO) Annex 14 and the
Australian standards for the transitional surfaces was not clear on how they should be applied when the runway strip width (as permitted) was less than the standard. Both standards worked in practice where the strip width and associated OLS met the standard dimensions. However, the wording of the respective standards was open to different interpretations for addressing the misalignment between the runway strip width and the inner edge of the approach surface. Neither ICAO or the Civil Aviation Safety Authority provided guidance in support of their respective interpretations.”
“With a runway 08/26 strip width of 180 m and approach inner edge of 300 m (for runway 26), as detailed in the OLS diagram and per the CASA 2 October 2003 advice, the buildings associated with the Bulla Road Precinct did not infringe the respective transitional surface. These dimensions were used for the basis of the major development plan.”
“Since 1972, successive aerodrome operators had published a 180 m strip width for runway 08/26. However, in 2005, when the Bulla Road Precinct was developed, it was unlikely that the aerodrome standards against which the strip width was based had been adequately determined to assure compliance against those standard.”
“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 alongside the approach surface and the other part alongside the published runway strip. With the different dimensions of the inner edge of the approach surface and runway strip, the transitional surfaces were misaligned.”
There are many more, mostly worth the time – and they do help clarify the bulk. IMO the only two questions which really need to be answered go begging. MTF..
Toot – toot.