ASD-B IN – A different perspective on the recent hype
Thread Starter
ASD-B IN – A different perspective on the recent hype
My attention was recently drawn to a rather curious post by the ATSB on LinkedIn, about the ASD-B rebate. The post says:
To incentivise voluntary uptake of ADS-B installations in Australian–registered aircraft operating under Visual Flight Rules (VFR), the government is providing a 50 per cent rebate on the purchase cost – capped to $5,000 – of eligible devices and, where applicable, the installation. While eligibility rests on equipment providing an ADS-B OUT capability, devices that provide ADS-B IN, as well as low-cost portable ADS-B devices, are also eligible for the grant.
Hear from a NSW aero club who recently installed ADS-B thanks to the grant, learn how AMSA can use ADS-B data to better affect a rescue during a search, and how we can use ADS-B in our investigations to ultimately improve aviation safety by reading this [linked article].
The linked article includes these statements attributed to Angus Mitchell, the ATSB’s Chief Commissioner:
I too urge everyone to take advantage of the rebate. But let’s get some perspective on what’s happening here.
The aim of the ADS-B rebate for VFR aircraft is not – or at least it was not originally - to improve the situational awareness and safety of VFR pilots, though that may coincidentally be an outcome in some limited circumstances. Nor is the aim of the rebate to make ATSB’s and AMSA’s jobs easier, though that may also be a coincidental outcome.
The primary aim of the rebate was – and so far as I can tell, remains - to make VFR aircraft more conspicuous – electronically – to IFR aircraft and the air navigation services system, so as to reduce the risks to IFR aircraft. Now the focus appears to have shifted to ADS-B IN and its claimed safety benefits for both IFR and VFR aircraft, even though ADS-B IN was not originally mandated for IFR aircraft.
I suggest that the shift in focus is in substantial part due to intractable inadequacies in air navigation services and airspace arrangements. Hopefully the ATSB is keeping an expert eye on those issues?
I also suggest that the ATSB should be a little more circumspect in extolling the benefits of ADS-B IN, particularly for VFR aircraft. There are many ‘ifs’ in a sentence that can logically conclude with ATSB’s statement that ADS-B IN: “greatly improves a pilot’s situational awareness and enhances the safety of their flight.”
Those ‘ifs’ include: If the pilot knows what the specific ADS-B IN system being used can do; If the pilot knows how to get the system to do that; If the pilot knows the failure modes of the system; If the pilot knows how to and does confirm the system is actually doing what the pilot assumes and hopes it’s doing and, most importantly: If the pilot always bears in mind than an absence of ADS-B IN returns (and radio silence) is no guarantee of the absence of other aircraft in the vicinity.
These extracts from an NTSB recommendation dated 13 May 2022 neatly summarise the intersecting limitations of see-and-avoid and ADS-B systems, while highlighting that even the ‘biggest and best’ ADS-B IN systems with traffic information displays and visual and aural conflict alert capabilities are not a situational awareness panacea, especially when the systems are not doing what pilots incorrectly assume they are doing:
Over the last 2 decades, automatic dependent surveillance-broadcast (ADS-B)-supported collision avoidance technologies featuring displays of traffic and aural and visual alerting features have become widely available and increasingly affordable in the United States. Such technologies, if widely adopted, could substantially reduce the occurrence of midair collisions like this one. Surprisingly, the pilots of both aircraft involved in the Ketchikan accident had ADS-B-supported cockpit displays of traffic information (CDTI) available to them, but the systems installed in each airplane had certain limitations, and they were not effectively utilized. The ADS-B system on the Otter was not broadcasting pressure altitude information because an ADS- B control head that relayed pressure altitude information to the ADS-B transceiver was not switched on. The NTSB’s investigation determined that this device was turned off during a maintenance inspection performed 2 weeks earlier on the Otter, and its deactivation was not noticed by three different pilots (including the accident pilot) who subsequently operated the airplane. Pilots did not normally manipulate the ADS-B control head, and it was not listed on company checklists for the airplane. As a result, information about the Otter’s pressure altitude was not transmitted to the Beaver’s ADS-B system.
The Beaver’s ADS-B system supplied traffic information to a ForeFlight mobile application that could provide a CDTI on the Beaver pilot’s Apple iPad. The version of ForeFlight on the iPad had the ability to produce both visual and aural alerts but required the altitude of relevant traffic targets to do so. Because the Otter was not broadcasting pressure altitude and though it was transmitting GPS-based altitude, the transceiver on the Beaver was configured to only transmit pressure altitude, not geometric altitude, to the iPad. As a result, the ForeFlight application on the Beaver did not have altitude information about the Otter and so would not have identified the Otter as a collision threat or produced an alert as the airplanes converged. Additionally, if the Beaver’s ForeFlight “Hide Distant Traffic” option had been enabled, the Otter would not have been displayed at all (the lack of altitude data for the Otter would have resulted in the ForeFlight application treating it as a “distant” target). Simulations performed by the NTSB indicated that, if the Otter had been broadcasting pressure altitude, the ForeFlight application could have generated aural and visual alerts concerning the Otter 1 minute 44 seconds before the collision.
The Otter was equipped with a Chelton electronic flight instrumentation system that provided a CDTI on a display mounted on the instrument panel. The Chelton system was designed to produce aural and visual traffic alerts but, to do so, required that the relevant traffic messages it received from the transceiver (a FreeFlight RANGR 978) be in “alert status.” Although the Otter was originally equipped with a transceiver that could place targets in “alert status,” in 2015, the transceiver was replaced with a newer model that did not have, and was not required to have, such an algorithm. After this change, the alerting features available on the CDTI could not be activated. Therefore, although the Beaver was displayed on the CDTI, the Otter pilot did not receive any visual or aural alerts concerning the Beaver as the airplanes converged. Simulations performed by the NTSB indicated that a CDTI with alerting capability might have generated an alert concerning the Beaver 37 seconds before the collision.
According to the Otter pilot, the last time he looked at the CDTI was about 4 minutes before the accident. At that time, he saw “two groups of blue triangles,” or aircraft targets, several miles away; but his experience with common patterns of flight operations in the local area led him to believe that the targets would not intercept his intended flightpath. If the Otter pilot had subsequently been alerted to the approaching Beaver, he would likely have looked for the Beaver and maneuvered to avoid it.
The NTSB determined that the probable cause of this accident was the inherent limitations of the see-and-avoid concept, which prevented the two pilots from seeing the other airplane before the collision, and the absence of visual and aural alerts from both airplanes’ traffic display systems, while operating in a geographic area with a high concentration of air tour activity. Contributing to the accident were (1) the Federal Aviation Administration’s (FAA’s) provision of new transceivers that lacked alerting capability to Capstone Program operators without adequately mitigating the increased risk associated with the consequent loss of the previously available alerting capability and (2) the absence of a requirement for airborne traffic advisory systems with aural alerting among operators who carry passengers for hire.
This accident highlights how CDTI with traffic alerting can help pilots to overcome the limitations of the see-and-avoid concept and can mitigate the risk of midair collisions. As demonstrated in this accident, the presence of a CDTI in the cockpit does not by itself guarantee the effectiveness of the technology.
Pilots must be familiar with ADS-B equipment installed in their aircraft and ensure that it is always fully operational in flight. Pilots should know whether their equipment includes a conflict-alerting feature and, if so, what types of alerts will be given under different scenarios. Because of the variety of CDTIs available and the different capabilities of these systems, pilots might not be aware of the aural or visual information their system can provide. Understanding the potential differences between CDTIs is particularly important for pilots who fly multiple aircraft with different systems. If a CDTI with aural and visual alerting is not installed, one should be installed and consistently used. Pilots must continue to visually scan outside for conflicting traffic in visual flight rules conditions, but the circumstances of this accident underscore the importance of combining an effective visual scan with CDTIs and alerting in the cockpit.
We’re all aware of the limitations of ‘see and avoid’. But the mitigation for those limitations at least so far as VFR pilots are concerned is not to stare at the screen of a gizmo in the cockpit displaying ADS-B IN symbols, trying to work out what they mean. Most of the ADS returns displayed on my EFB come from aircraft in the flight levels and are, particularly when flying anywhere in the ‘J curve’, a distraction from the real job of a VFR pilot.
It is true that ADS-B and other systems enable Centre to alert aircraft even in G airspace - whether VFR or IFR - that they are in potential conflict. I hear it quite often on the Area frequency and am thankful that it happens. But it’s also true that Centre is only doing that for VFR on a ‘workload permitting’ basis and sometimes the workload does not permit the provision of that ‘nice-to-have’ service. Radio silence from Centre is therefore not conclusive of an absence of potentially conflicting traffic.
Just look at the Ballina SFIS - not a ‘nice-to-have’ but a ‘supposed-to-be-delivered’ service due to the traffic density and consequent collision risks in the area - to see what happens when the air navigation service provider has higher priorities. The SFIS is simply NOTAMed ‘no-can-do’. But the traffic density and consequent collision risks don’t go away. Perhaps the airspace classification and dimension arrangements in the Ballina area remain a substantial part of the safety problem, ATSB?
And then there’s the Mangalore tragedy in which the air navigation service provider’s equipment reliably and accurately tracked and displayed two ADS-B equipped IFR aircraft in G airspace to the point of their mid-air collision and four fatalities, generating four Short Term Conflict Alerts for ATC along the way to the collision. That was after the ADS-B mandate for IFR aircraft was justified on the basis that it would help prevent precisely what happened. This from the ATSB report on the tragedy:
- the STCA was designed as an alert for a breakdown in separation standards
- there was no set separation standard in non-controlled airspace
- the pilots were responsible for their own separation
they decided that a safety alert or traffic avoidance advice was not required, and cleared the aural alert.
The equipment on the two IFR aircraft generated what the air navigation service system construed as “nuisance” alerts – “an alert which is correctly generated according to the defined STCA system parameters (rule set), but is considered operationally inappropriate by the controller” - discussed further in the ATSB report. Many people were – and remain – astonished and appalled at that outcome.
Many of those alerts would not be construed as “nuisances” and dismissed as such if they occurred in airspace with separation standards. But changing the airspace arrangements around places like Mangalore and Ballina and… would create “nuisances” of a different kind: The airspace regulator would have to make those changes and the air navigation service provider have to employ more controllers.
Problem: What to do to shift the focus away from inadequate air navigation services and airspace arrangements, so as not to upset that status quo, while doing something that seems to address the risk of another IFR/IFR mid-air collision?
Solution: Encourage everyone to get ADS-B IN.
That way, Airservices is under less pressure to provide better or more services, ATSB continues to get all the data to help explain, in three dimensional graphic detail, the track to the smoking hole and AMSA continues to get all the data to better “affect” - I think the correct word in the context of ATSB’s statement is “effect” - a rescue if anyone survives. Meanwhile, the aviation safety and airspace regulator – CASA keeps its lips pursed and avoids eye contact. A new cockpit gizmo, subsidised by someone else, is an excellent solution for all the agencies concerned. Pats on the back all round!
VFR pilots should make no mistake: Our biggest risk - aside from inadvertent entry into IMC or fuel exhaustion or starvation - arises from being ‘heads down’ in the cockpit rather than keeping a proper lookout. There are of course visibility limitations created by airframe structures of every aircraft and the relative locations of other aircraft in flight. But it’s certain a pilot’s not going to see anything anywhere outside the aircraft while ever the pilot’s focusing on a gizmo in the cockpit and making the assumption it’s a source of traffic truth.
Assumptions about the absence of conflicting returns on a ADS-B IN system display and silence on the radio can lead to a dangerous false sense of safety. Just as there are plenty of explanations for silence on the radio, only one of which is the absence of other aircraft in the vicinity, there are plenty of explanations for no ADS-B IN system returns, or inaccurate information, on an ADS-B IN display. (Most of the traffic based at my local aerodrome involves aircraft that have no ADS or SSR transponder - at least none that’s switched on - whose pilots are best described as ‘taciturn’.)
There are plenty of examples of VFR pilots seeing an ADS-B IN return on their EFB and using that information to see and avoid - or mutually arrange separation from - another aircraft. And there are plenty of examples of IFR aircraft seeing VFR ADS information and doing the same. And that’s a great outcome. But those pilots don’t know what traffic wasn’t displayed accurately or at all in their cockpits at the time. There is no guarantee that all traffic in the vicinity will ever be displayed by ADS-B IN systems. And as with any other aircraft system, you have to know what the specific ADS-B IN system you’re using can do, how to get it to do what it can do and how to confirm it's actually doing what you assume and hope it’s doing, and that means understanding the system’s failure modes.
For all those reasons and more, I consider this to be an overstatement by ATSB:
There are lots of “ifs” missing from that sentence and the ATSB’s categorical “would have” conclusion. Both the Otter and Beaver in the Alaska tragedy were equipped with ADS-B IN but that didn’t result in either pilot comprehending the location of the other’s aircraft into which they collided.
The ATSB went on to say:
Could have. If. Probably. The Beaver in the Alaska tragedy was carrying an EFB with a traffic alerting system. It didn’t work in the case of the Otter because the Otter was, unknown to its pilot and previous pilots, not broadcasting pressure altitude information. The Otter had traffic alerting capability, too. Until it was removed.
The equipment actually fitted to the Mangalore aircraft in compliance with regulatory requirements actually ‘triggered’ Short Term Conflict Alerts in the air navigation service system. Another description of those alerts is “advance warning of a potential collision”. That’s the verypurpose of STCAs. And the pilots of the aircraft probably assumed – reasonably I would suggest, given all of the safety hype around the original ADS-B mandate – that the air navigation service system would pass on those warnings rather than being justified in unilaterally dismissing them. Perhaps the tragic accident would have also been avoided if IFR pilots had clearly understood what a dangerously invalid assumption they were making about what the new ADS-B system was going to do for them.
On the subject of cockpit gizmos, there is one which is very cheap, very reliable, very accurate and almost pilot-proof: A modern carbon monoxide detector.
I mention carbon monoxide detectors because of the NSW Coroner’s Court inquiry and findings in the wake of the tragedy in which seven lives were lost in the Beaver accident at Jerusalem Bay in Sydney in 2017. One of the useful (and disturbing) things a modern CO detector will show you is the high level of CO to which we’re often exposed while just taxiing around on the ground (or water) in ‘ordinary’, serviceable aircraft. It will also help you to work out what to do with vents and windows to reduce the levels of exposure. Many of you will be blissfully unaware of the extent of your on-ground exposure and CASA remains wilfully blind to it, relying instead on reports from LAMES about defects found during maintenance and waiting for more CO exposure-caused fatalities and injuries.
In the course of the Coronial inquiry CASA was asked, in effect, how many more fatalities it would take before CO detectors would be mandated. According the Coroner, the CASA witness “frankly acknowledged”:
Translation: Affordable safety. CASA has decided that the value of lives potentially saved by mandating CO detection equipment is not sufficient to justify the mandate.
The evidence given by CASA was to the effect that there are approximately 8,365 single piston engine aircraft in operation in Australia and that dash-mounted CO detectors cost about $1,200. (Let’s set aside the fact that there are much cheaper options that are just as reliable and accurate, and include aural and visual alerts, as some panel mounted versions – remember how long it took to get rid of the fixed ELT mandate and how long it took for EFBs to be accepted by the regulator?) On CASA’s figures that’s about $10,000,000 to fit the single piston engine fleet. So, that means CASA reckons it’s not worthwhile spending $10,000,000 on CO detectors until the further body count makes it worthwhile.
In contrast, to justify CASA’s regulatory response in the wake of the Angel Flight tragedies involving a total of six fatalities (one near Nhill in 2011 the other near Mt Gambier in 2017), Dr Aleck of CASA said:
When asked by the Angel Flight CEO as to why CASA had chosen to by-pass the usual protocols for regulatory change, the then CEO of CASA said:
Why was CASA “prospective” rather than waiting for more accidents in the Angel Flight case, by-passing the usual regulatory change process, but is waiting for more fatalities and injuries in the case of CO detectors? Answer: The capricious consequences of politics. Pressure was put on CASA by the federal government to be seen to do something in the case of Angel Flight and, sadly for the next victims of CO exposure, the Beaver tragedy barely raised a federal government eyebrow in the direction of CO detectors. That’s probably because of the time it took to work out that CO exposure was a factor in the tragedy.
Get ADS-B IN by all means. But don’t believe all the hype. It’s not a panacea for situational awareness or the intractable inadequacies in air navigation services and airspace arrangements.
Yours in aviation safety.
We’re joining with the Australian Maritime Safety Authority in encouraging general and recreational aircraft owners to take advantage of the government’s Automatic Dependent Surveillance Broadcast (ADS-B) rebate program before it closes on 31 May next year.
To incentivise voluntary uptake of ADS-B installations in Australian–registered aircraft operating under Visual Flight Rules (VFR), the government is providing a 50 per cent rebate on the purchase cost – capped to $5,000 – of eligible devices and, where applicable, the installation. While eligibility rests on equipment providing an ADS-B OUT capability, devices that provide ADS-B IN, as well as low-cost portable ADS-B devices, are also eligible for the grant.
Hear from a NSW aero club who recently installed ADS-B thanks to the grant, learn how AMSA can use ADS-B data to better affect a rescue during a search, and how we can use ADS-B in our investigations to ultimately improve aviation safety by reading this [linked article].
“The need for improved situational awareness for pilots was evident during our investigation into the mid-air collision of two IFR training aircraft near Mangalore Airport in 2020. While both aircraft involved in the collision were operating under instrument flight rules (IFR) and equipped with ADS-B OUT, neither aircraft were equipped with ADS-B IN systems, and nor were they required to be.”
To support its investigation into the mid-air collision, the ATSB initiated an aircraft performance and cockpit visibility study to determine when each aircraft may have been visible to the pilots of the other aircraft. The study has clearly showed that had the aircraft been equipped with ADS-B IN, the pilots would have been assisted in locating the other aircraft and alerted to its position much earlier than by visual acquisition.
“Both a cockpit display of traffic information with an ADS-B traffic alerting system or an electronic conspicuity device connected to an electronic flight bag application could have provided this advance warning of a potential collision to the pilots of both aircraft with this tragic accident probably being avoided,” Mr Mitchell said.
To support its investigation into the mid-air collision, the ATSB initiated an aircraft performance and cockpit visibility study to determine when each aircraft may have been visible to the pilots of the other aircraft. The study has clearly showed that had the aircraft been equipped with ADS-B IN, the pilots would have been assisted in locating the other aircraft and alerted to its position much earlier than by visual acquisition.
“Both a cockpit display of traffic information with an ADS-B traffic alerting system or an electronic conspicuity device connected to an electronic flight bag application could have provided this advance warning of a potential collision to the pilots of both aircraft with this tragic accident probably being avoided,” Mr Mitchell said.
The aim of the ADS-B rebate for VFR aircraft is not – or at least it was not originally - to improve the situational awareness and safety of VFR pilots, though that may coincidentally be an outcome in some limited circumstances. Nor is the aim of the rebate to make ATSB’s and AMSA’s jobs easier, though that may also be a coincidental outcome.
The primary aim of the rebate was – and so far as I can tell, remains - to make VFR aircraft more conspicuous – electronically – to IFR aircraft and the air navigation services system, so as to reduce the risks to IFR aircraft. Now the focus appears to have shifted to ADS-B IN and its claimed safety benefits for both IFR and VFR aircraft, even though ADS-B IN was not originally mandated for IFR aircraft.
I suggest that the shift in focus is in substantial part due to intractable inadequacies in air navigation services and airspace arrangements. Hopefully the ATSB is keeping an expert eye on those issues?
I also suggest that the ATSB should be a little more circumspect in extolling the benefits of ADS-B IN, particularly for VFR aircraft. There are many ‘ifs’ in a sentence that can logically conclude with ATSB’s statement that ADS-B IN: “greatly improves a pilot’s situational awareness and enhances the safety of their flight.”
Those ‘ifs’ include: If the pilot knows what the specific ADS-B IN system being used can do; If the pilot knows how to get the system to do that; If the pilot knows the failure modes of the system; If the pilot knows how to and does confirm the system is actually doing what the pilot assumes and hopes it’s doing and, most importantly: If the pilot always bears in mind than an absence of ADS-B IN returns (and radio silence) is no guarantee of the absence of other aircraft in the vicinity.
These extracts from an NTSB recommendation dated 13 May 2022 neatly summarise the intersecting limitations of see-and-avoid and ADS-B systems, while highlighting that even the ‘biggest and best’ ADS-B IN systems with traffic information displays and visual and aural conflict alert capabilities are not a situational awareness panacea, especially when the systems are not doing what pilots incorrectly assume they are doing:
The National Transportation Safety Board’s (NTSB’s) final report on a fatal May 13, 2019, midair collision between a de Havilland DHC-2 Beaver and a de Havilland DHC-3 Otter near Ketchikan, Alaska, which occurred at 1221 local time in visual meteorological conditions, has highlighted once again the limitations of see-and-avoid. An analysis of the visibility of each airplane from the cockpit of the other indicated that the Otter was obscured from the Beaver pilot by the Beaver’s cockpit structure, right wing, and the passenger in the right front seat. Similarly, the Beaver was intermittently obscured from the Otter pilot’s field of view by a window post, most critically during the last 11 seconds before the collision. [Six deaths and nine serious injuries ensued.]
Over the last 2 decades, automatic dependent surveillance-broadcast (ADS-B)-supported collision avoidance technologies featuring displays of traffic and aural and visual alerting features have become widely available and increasingly affordable in the United States. Such technologies, if widely adopted, could substantially reduce the occurrence of midair collisions like this one. Surprisingly, the pilots of both aircraft involved in the Ketchikan accident had ADS-B-supported cockpit displays of traffic information (CDTI) available to them, but the systems installed in each airplane had certain limitations, and they were not effectively utilized. The ADS-B system on the Otter was not broadcasting pressure altitude information because an ADS- B control head that relayed pressure altitude information to the ADS-B transceiver was not switched on. The NTSB’s investigation determined that this device was turned off during a maintenance inspection performed 2 weeks earlier on the Otter, and its deactivation was not noticed by three different pilots (including the accident pilot) who subsequently operated the airplane. Pilots did not normally manipulate the ADS-B control head, and it was not listed on company checklists for the airplane. As a result, information about the Otter’s pressure altitude was not transmitted to the Beaver’s ADS-B system.
The Beaver’s ADS-B system supplied traffic information to a ForeFlight mobile application that could provide a CDTI on the Beaver pilot’s Apple iPad. The version of ForeFlight on the iPad had the ability to produce both visual and aural alerts but required the altitude of relevant traffic targets to do so. Because the Otter was not broadcasting pressure altitude and though it was transmitting GPS-based altitude, the transceiver on the Beaver was configured to only transmit pressure altitude, not geometric altitude, to the iPad. As a result, the ForeFlight application on the Beaver did not have altitude information about the Otter and so would not have identified the Otter as a collision threat or produced an alert as the airplanes converged. Additionally, if the Beaver’s ForeFlight “Hide Distant Traffic” option had been enabled, the Otter would not have been displayed at all (the lack of altitude data for the Otter would have resulted in the ForeFlight application treating it as a “distant” target). Simulations performed by the NTSB indicated that, if the Otter had been broadcasting pressure altitude, the ForeFlight application could have generated aural and visual alerts concerning the Otter 1 minute 44 seconds before the collision.
The Otter was equipped with a Chelton electronic flight instrumentation system that provided a CDTI on a display mounted on the instrument panel. The Chelton system was designed to produce aural and visual traffic alerts but, to do so, required that the relevant traffic messages it received from the transceiver (a FreeFlight RANGR 978) be in “alert status.” Although the Otter was originally equipped with a transceiver that could place targets in “alert status,” in 2015, the transceiver was replaced with a newer model that did not have, and was not required to have, such an algorithm. After this change, the alerting features available on the CDTI could not be activated. Therefore, although the Beaver was displayed on the CDTI, the Otter pilot did not receive any visual or aural alerts concerning the Beaver as the airplanes converged. Simulations performed by the NTSB indicated that a CDTI with alerting capability might have generated an alert concerning the Beaver 37 seconds before the collision.
According to the Otter pilot, the last time he looked at the CDTI was about 4 minutes before the accident. At that time, he saw “two groups of blue triangles,” or aircraft targets, several miles away; but his experience with common patterns of flight operations in the local area led him to believe that the targets would not intercept his intended flightpath. If the Otter pilot had subsequently been alerted to the approaching Beaver, he would likely have looked for the Beaver and maneuvered to avoid it.
The NTSB determined that the probable cause of this accident was the inherent limitations of the see-and-avoid concept, which prevented the two pilots from seeing the other airplane before the collision, and the absence of visual and aural alerts from both airplanes’ traffic display systems, while operating in a geographic area with a high concentration of air tour activity. Contributing to the accident were (1) the Federal Aviation Administration’s (FAA’s) provision of new transceivers that lacked alerting capability to Capstone Program operators without adequately mitigating the increased risk associated with the consequent loss of the previously available alerting capability and (2) the absence of a requirement for airborne traffic advisory systems with aural alerting among operators who carry passengers for hire.
This accident highlights how CDTI with traffic alerting can help pilots to overcome the limitations of the see-and-avoid concept and can mitigate the risk of midair collisions. As demonstrated in this accident, the presence of a CDTI in the cockpit does not by itself guarantee the effectiveness of the technology.
Pilots must be familiar with ADS-B equipment installed in their aircraft and ensure that it is always fully operational in flight. Pilots should know whether their equipment includes a conflict-alerting feature and, if so, what types of alerts will be given under different scenarios. Because of the variety of CDTIs available and the different capabilities of these systems, pilots might not be aware of the aural or visual information their system can provide. Understanding the potential differences between CDTIs is particularly important for pilots who fly multiple aircraft with different systems. If a CDTI with aural and visual alerting is not installed, one should be installed and consistently used. Pilots must continue to visually scan outside for conflicting traffic in visual flight rules conditions, but the circumstances of this accident underscore the importance of combining an effective visual scan with CDTIs and alerting in the cockpit.
It is true that ADS-B and other systems enable Centre to alert aircraft even in G airspace - whether VFR or IFR - that they are in potential conflict. I hear it quite often on the Area frequency and am thankful that it happens. But it’s also true that Centre is only doing that for VFR on a ‘workload permitting’ basis and sometimes the workload does not permit the provision of that ‘nice-to-have’ service. Radio silence from Centre is therefore not conclusive of an absence of potentially conflicting traffic.
Just look at the Ballina SFIS - not a ‘nice-to-have’ but a ‘supposed-to-be-delivered’ service due to the traffic density and consequent collision risks in the area - to see what happens when the air navigation service provider has higher priorities. The SFIS is simply NOTAMed ‘no-can-do’. But the traffic density and consequent collision risks don’t go away. Perhaps the airspace classification and dimension arrangements in the Ballina area remain a substantial part of the safety problem, ATSB?
And then there’s the Mangalore tragedy in which the air navigation service provider’s equipment reliably and accurately tracked and displayed two ADS-B equipped IFR aircraft in G airspace to the point of their mid-air collision and four fatalities, generating four Short Term Conflict Alerts for ATC along the way to the collision. That was after the ADS-B mandate for IFR aircraft was justified on the basis that it would help prevent precisely what happened. This from the ATSB report on the tragedy:
When each of the STCAs displayed, the controller assessed the integrity of the alert in accordance with the [National ATS procedures manual] procedure. The controller reported checking the path of each aircraft using the set velocity vectors, the vertical separation of the aircraft, and confirming that traffic information about each aircraft had been passed to the other aircraft. Having assessed that the aircraft would pass each other and:
- the STCA was designed as an alert for a breakdown in separation standards
- there was no set separation standard in non-controlled airspace
- the pilots were responsible for their own separation
they decided that a safety alert or traffic avoidance advice was not required, and cleared the aural alert.
Many of those alerts would not be construed as “nuisances” and dismissed as such if they occurred in airspace with separation standards. But changing the airspace arrangements around places like Mangalore and Ballina and… would create “nuisances” of a different kind: The airspace regulator would have to make those changes and the air navigation service provider have to employ more controllers.
Problem: What to do to shift the focus away from inadequate air navigation services and airspace arrangements, so as not to upset that status quo, while doing something that seems to address the risk of another IFR/IFR mid-air collision?
Solution: Encourage everyone to get ADS-B IN.
That way, Airservices is under less pressure to provide better or more services, ATSB continues to get all the data to help explain, in three dimensional graphic detail, the track to the smoking hole and AMSA continues to get all the data to better “affect” - I think the correct word in the context of ATSB’s statement is “effect” - a rescue if anyone survives. Meanwhile, the aviation safety and airspace regulator – CASA keeps its lips pursed and avoids eye contact. A new cockpit gizmo, subsidised by someone else, is an excellent solution for all the agencies concerned. Pats on the back all round!
VFR pilots should make no mistake: Our biggest risk - aside from inadvertent entry into IMC or fuel exhaustion or starvation - arises from being ‘heads down’ in the cockpit rather than keeping a proper lookout. There are of course visibility limitations created by airframe structures of every aircraft and the relative locations of other aircraft in flight. But it’s certain a pilot’s not going to see anything anywhere outside the aircraft while ever the pilot’s focusing on a gizmo in the cockpit and making the assumption it’s a source of traffic truth.
Assumptions about the absence of conflicting returns on a ADS-B IN system display and silence on the radio can lead to a dangerous false sense of safety. Just as there are plenty of explanations for silence on the radio, only one of which is the absence of other aircraft in the vicinity, there are plenty of explanations for no ADS-B IN system returns, or inaccurate information, on an ADS-B IN display. (Most of the traffic based at my local aerodrome involves aircraft that have no ADS or SSR transponder - at least none that’s switched on - whose pilots are best described as ‘taciturn’.)
There are plenty of examples of VFR pilots seeing an ADS-B IN return on their EFB and using that information to see and avoid - or mutually arrange separation from - another aircraft. And there are plenty of examples of IFR aircraft seeing VFR ADS information and doing the same. And that’s a great outcome. But those pilots don’t know what traffic wasn’t displayed accurately or at all in their cockpits at the time. There is no guarantee that all traffic in the vicinity will ever be displayed by ADS-B IN systems. And as with any other aircraft system, you have to know what the specific ADS-B IN system you’re using can do, how to get it to do what it can do and how to confirm it's actually doing what you assume and hope it’s doing, and that means understanding the system’s failure modes.
For all those reasons and more, I consider this to be an overstatement by ATSB:
To support its investigation into the [Mangalore] mid-air collision, the ATSB initiated an aircraft performance and cockpit visibility study to determine when each aircraft may have been visible to the pilots of the other aircraft. The study clearly showed that had the aircraft been equipped with ADS-B IN, the pilots would have been assisted in locating the other aircraft and alerted to its position much earlier than by visual acquisition.
The ATSB went on to say:
Both a cockpit display of traffic information with an ADS-B traffic alerting system or an electronic conspicuity device connected to an electronic flight bag application could have provided this advance warning of a potential collision to the pilots of both aircraft with this tragic accident probably being avoided.
The equipment actually fitted to the Mangalore aircraft in compliance with regulatory requirements actually ‘triggered’ Short Term Conflict Alerts in the air navigation service system. Another description of those alerts is “advance warning of a potential collision”. That’s the verypurpose of STCAs. And the pilots of the aircraft probably assumed – reasonably I would suggest, given all of the safety hype around the original ADS-B mandate – that the air navigation service system would pass on those warnings rather than being justified in unilaterally dismissing them. Perhaps the tragic accident would have also been avoided if IFR pilots had clearly understood what a dangerously invalid assumption they were making about what the new ADS-B system was going to do for them.
On the subject of cockpit gizmos, there is one which is very cheap, very reliable, very accurate and almost pilot-proof: A modern carbon monoxide detector.
I mention carbon monoxide detectors because of the NSW Coroner’s Court inquiry and findings in the wake of the tragedy in which seven lives were lost in the Beaver accident at Jerusalem Bay in Sydney in 2017. One of the useful (and disturbing) things a modern CO detector will show you is the high level of CO to which we’re often exposed while just taxiing around on the ground (or water) in ‘ordinary’, serviceable aircraft. It will also help you to work out what to do with vents and windows to reduce the levels of exposure. Many of you will be blissfully unaware of the extent of your on-ground exposure and CASA remains wilfully blind to it, relying instead on reports from LAMES about defects found during maintenance and waiting for more CO exposure-caused fatalities and injuries.
In the course of the Coronial inquiry CASA was asked, in effect, how many more fatalities it would take before CO detectors would be mandated. According the Coroner, the CASA witness “frankly acknowledged”:
To be honest I'd say it would take probably unfortunately a number of accidents, hopefully not fatal, to trigger the risk level to be in the range where regulatory action would be required.
The evidence given by CASA was to the effect that there are approximately 8,365 single piston engine aircraft in operation in Australia and that dash-mounted CO detectors cost about $1,200. (Let’s set aside the fact that there are much cheaper options that are just as reliable and accurate, and include aural and visual alerts, as some panel mounted versions – remember how long it took to get rid of the fixed ELT mandate and how long it took for EFBs to be accepted by the regulator?) On CASA’s figures that’s about $10,000,000 to fit the single piston engine fleet. So, that means CASA reckons it’s not worthwhile spending $10,000,000 on CO detectors until the further body count makes it worthwhile.
In contrast, to justify CASA’s regulatory response in the wake of the Angel Flight tragedies involving a total of six fatalities (one near Nhill in 2011 the other near Mt Gambier in 2017), Dr Aleck of CASA said:
Our objective here is not to specifically address what caused those two accidents; it's to address what kinds of things can cause incidents and accidents of this kind. We're being prospective. If we were to wait for sufficiently robust data to support an evidence-based decision for every individual decision we took in this space, we would have to wait for a dozen or more accidents to occur.
I have the power; because it’s easy.
Get ADS-B IN by all means. But don’t believe all the hype. It’s not a panacea for situational awareness or the intractable inadequacies in air navigation services and airspace arrangements.
Yours in aviation safety.
The following 9 users liked this post by Clinton McKenzie:
I’ve been harping on about this for a while now… ADSB OUT is next to useless without ADSB IN.
Unless you are in direct contact with ATC then you are back to see and avoid. (But as we’ve seen even if you ARE in contact with them, it may not help!)
IN gives you a fighting chance to see someone in advance.
The sooner everyone gets ADSB out, the better, even if it’s just a SkyEcho.
Unless you are in direct contact with ATC then you are back to see and avoid. (But as we’ve seen even if you ARE in contact with them, it may not help!)
IN gives you a fighting chance to see someone in advance.
The sooner everyone gets ADSB out, the better, even if it’s just a SkyEcho.
I know FR24 has its limitations but I use it as a situational awareness aid and it is effectively ADSB IN if you are in a mobile coverage area. It’s also displayed on Avplan (but not on OzRunways I believe). However, eyes out of the window is my best defence. Just a few hours ago a foreign student in an FTA Diamond made a very poor departure call while I was flying in the vicinity. It was visible on FR24 and that greatly assisted in spotting it visually.
Cloudee, get yourself a Stratus box or a “Ping” ADSB-in device and you’ll see the traffic real-time from aircraft to aircraft, right there on your phone or EFB without the delays and latency of the 4G system.
Better still, if you can afford it and you are flying in different aircraft / not your own, try to stretch for a SkyEcho.
Better still, if you can afford it and you are flying in different aircraft / not your own, try to stretch for a SkyEcho.
The following 2 users liked this post by Squawk7700:
Doesn't the rebate cover a SkyEcho device as well?
Thread Starter
The following users liked this post:
As the saying goes: It's the one you don't see that'll get ya.
ADSB/ACAS/TCAS are all fallback devices, that is when the human fails to keep the picture the devices take over. I'm all for reasonable implementation of these things, however it should be very well understood that it does not replace the basics of situational awareness, lookout and monitoring the appropriate radio frequency. Some simple things that add to situational awareness; Listen to the Aerodrome frequency from quite a distance out, especially if you have two comms, you do not have to transmit, you are just listening for possible conflicts. Make informative, concise radio calls at the appropriate time, too early and new traffic won't hear you, too late and you already could be a conflict, anywhere near the circuit and approach paths (ie 5 mile final) is too late. Remember VHF is line of sight, if you are approaching an airport in hills, make another call when the airport is LOS, same on departing, make a departure call when at sufficient height so inbound aircraft can hear your departure track. Make calls BEFORE you do something, making an entering x runway as you are already entering defeats the purpose, you have already pulled out in front of possible traffic, you have not given other traffic the chance to announce a conflict. And of course don't let yourself get distracted when approaching an aerodrome, make sure there's no big checklists, passengers moving around, ask them to keep the chatter down if it's taking up your head space so you can concentrate on the approach, landing and any traffic. And of course be predictable, don't get in the habit of rushing, or anything unusual like tight circuits, straight in approaches etc without clearly stating that on the radio. Being on a normal length predictable circuit not only helps promote stable approach, but also gives other traffic more time to sight you.
The following 3 users liked this post by 43Inches:
ADSB/And of course be predictable, don't get in the habit of rushing, or anything unusual like tight circuits, straight in approaches etc without clearly stating that on the radio. Being on a normal length predictable circuit not only helps promote stable approach, but also gives other traffic more time to sight you.
Thread Starter
Another advertisement from the ATSB about ADS-B IN.
This time the advert has been triggered by a “near collision” between two VFR aircraft in the Moorabbin training area.
VFR aircraft.
In a Delta area.
The ATSB keeps dealing with this issue as if there are only ever ‘isolated pairs’ of aircraft. One Sling and one Piper Cherokee. One Seminole and one Travel Air.
If all the ‘ifs’ line up and there are just two aircraft in proximity, laterally, and the pilot of one or both aircraft ‘see’ and accurately interpret the traffic display of ADS-B IN at a glance down in the cockpit, great. But then there’s the common reality of busy airspace.
Which of the displayed aircraft, if any, is a collision risk to me on my track WAD - TWRN? (This is just a snapshot from the EFB provider supplied data, without my conspicuity device connected. Just assume they are ADS-B IN symbols in green.) You have the luxury of looking at a much bigger and stable display on your computer monitor.
(The latest ATSB advert includes a text box that says: “ATC Short Term Conflict Alert (STCA) between AEM and JQF.” Maybe Airservices should do in the Melbourne FIR what’s been done in the Brisbane FIR: Just turn off the SCTA functionality below 4,500’ so that ATC is not bothered by the nuisance.)
I finally note, again, that the Beaver and Otter in the Alaska tragedy were both fitted with ADS-B IN with all sorts of bells and whistles alerting capability … that wasn't functioning properly.
This time the advert has been triggered by a “near collision” between two VFR aircraft in the Moorabbin training area.
VFR aircraft.
In a Delta area.
The ATSB keeps dealing with this issue as if there are only ever ‘isolated pairs’ of aircraft. One Sling and one Piper Cherokee. One Seminole and one Travel Air.
If all the ‘ifs’ line up and there are just two aircraft in proximity, laterally, and the pilot of one or both aircraft ‘see’ and accurately interpret the traffic display of ADS-B IN at a glance down in the cockpit, great. But then there’s the common reality of busy airspace.
Which of the displayed aircraft, if any, is a collision risk to me on my track WAD - TWRN? (This is just a snapshot from the EFB provider supplied data, without my conspicuity device connected. Just assume they are ADS-B IN symbols in green.) You have the luxury of looking at a much bigger and stable display on your computer monitor.
(The latest ATSB advert includes a text box that says: “ATC Short Term Conflict Alert (STCA) between AEM and JQF.” Maybe Airservices should do in the Melbourne FIR what’s been done in the Brisbane FIR: Just turn off the SCTA functionality below 4,500’ so that ATC is not bothered by the nuisance.)
I finally note, again, that the Beaver and Otter in the Alaska tragedy were both fitted with ADS-B IN with all sorts of bells and whistles alerting capability … that wasn't functioning properly.
Last edited by Clinton McKenzie; 2nd Nov 2023 at 05:05.
Another advertisement from the ATSB about ADS-B IN.
This time the advert has been triggered by a “near collision” between two VFR aircraft in the Moorabbin training area.
VFR aircraft.
In a Delta area.
The ATSB keeps dealing with this issue as if there are only ever ‘isolated pairs’ of aircraft. One Sling and one Piper Cherokee. One Seminole and one Travel Air.
This time the advert has been triggered by a “near collision” between two VFR aircraft in the Moorabbin training area.
VFR aircraft.
In a Delta area.
The ATSB keeps dealing with this issue as if there are only ever ‘isolated pairs’ of aircraft. One Sling and one Piper Cherokee. One Seminole and one Travel Air.
The issue I have with ADSB-in (with or without all the bells and whistles) is the distraction it can cause visually looking for an aircraft that might or might not be in conflict (depending upon the actions of the other guy who, by definition is doing the same as you) whilst not seeing the aircraft without ADSB fitted at all!! As I've said before, it's the one you don't see that'll get you.
My attention was recently drawn to a rather curious post by the ATSB on LinkedIn, about the ASD-B rebate. The post says:The linked article includes these statements attributed to Angus Mitchell, the ATSB’s Chief Commissioner:I too urge everyone to take advantage of the rebate. But let’s get some perspective on what’s happening here.
The aim of the ADS-B rebate for VFR aircraft is not – or at least it was not originally - to improve the situational awareness and safety of VFR pilots, though that may coincidentally be an outcome in some limited circumstances. Nor is the aim of the rebate to make ATSB’s and AMSA’s jobs easier, though that may also be a coincidental outcome.
The primary aim of the rebate was – and so far as I can tell, remains - to make VFR aircraft more conspicuous – electronically – to IFR aircraft and the air navigation services system, so as to reduce the risks to IFR aircraft. Now the focus appears to have shifted to ADS-B IN and its claimed safety benefits for both IFR and VFR aircraft, even though ADS-B IN was not originally mandated for IFR aircraft.
I suggest that the shift in focus is in substantial part due to intractable inadequacies in air navigation services and airspace arrangements. Hopefully the ATSB is keeping an expert eye on those issues?
I also suggest that the ATSB should be a little more circumspect in extolling the benefits of ADS-B IN, particularly for VFR aircraft. There are many ‘ifs’ in a sentence that can logically conclude with ATSB’s statement that ADS-B IN: “greatly improves a pilot’s situational awareness and enhances the safety of their flight.”
Those ‘ifs’ include: If the pilot knows what the specific ADS-B IN system being used can do; If the pilot knows how to get the system to do that; If the pilot knows the failure modes of the system; If the pilot knows how to and does confirm the system is actually doing what the pilot assumes and hopes it’s doing and, most importantly: If the pilot always bears in mind than an absence of ADS-B IN returns (and radio silence) is no guarantee of the absence of other aircraft in the vicinity.
These extracts from an NTSB recommendation dated 13 May 2022 neatly summarise the intersecting limitations of see-and-avoid and ADS-B systems, while highlighting that even the ‘biggest and best’ ADS-B IN systems with traffic information displays and visual and aural conflict alert capabilities are not a situational awareness panacea, especially when the systems are not doing what pilots incorrectly assume they are doing:We’re all aware of the limitations of ‘see and avoid’. But the mitigation for those limitations at least so far as VFR pilots are concerned is not to stare at the screen of a gizmo in the cockpit displaying ADS-B IN symbols, trying to work out what they mean. Most of the ADS returns displayed on my EFB come from aircraft in the flight levels and are, particularly when flying anywhere in the ‘J curve’, a distraction from the real job of a VFR pilot.
It is true that ADS-B and other systems enable Centre to alert aircraft even in G airspace - whether VFR or IFR - that they are in potential conflict. I hear it quite often on the Area frequency and am thankful that it happens. But it’s also true that Centre is only doing that for VFR on a ‘workload permitting’ basis and sometimes the workload does not permit the provision of that ‘nice-to-have’ service. Radio silence from Centre is therefore not conclusive of an absence of potentially conflicting traffic.
Just look at the Ballina SFIS - not a ‘nice-to-have’ but a ‘supposed-to-be-delivered’ service due to the traffic density and consequent collision risks in the area - to see what happens when the air navigation service provider has higher priorities. The SFIS is simply NOTAMed ‘no-can-do’. But the traffic density and consequent collision risks don’t go away. Perhaps the airspace classification and dimension arrangements in the Ballina area remain a substantial part of the safety problem, ATSB?
And then there’s the Mangalore tragedy in which the air navigation service provider’s equipment reliably and accurately tracked and displayed two ADS-B equipped IFR aircraft in G airspace to the point of their mid-air collision and four fatalities, generating four Short Term Conflict Alerts for ATC along the way to the collision. That was after the ADS-B mandate for IFR aircraft was justified on the basis that it would help prevent precisely what happened. This from the ATSB report on the tragedy:The equipment on the two IFR aircraft generated what the air navigation service system construed as “nuisance” alerts – “an alert which is correctly generated according to the defined STCA system parameters (rule set), but is considered operationally inappropriate by the controller” - discussed further in the ATSB report. Many people were – and remain – astonished and appalled at that outcome.
Many of those alerts would not be construed as “nuisances” and dismissed as such if they occurred in airspace with separation standards. But changing the airspace arrangements around places like Mangalore and Ballina and… would create “nuisances” of a different kind: The airspace regulator would have to make those changes and the air navigation service provider have to employ more controllers.
Problem: What to do to shift the focus away from inadequate air navigation services and airspace arrangements, so as not to upset that status quo, while doing something that seems to address the risk of another IFR/IFR mid-air collision?
Solution: Encourage everyone to get ADS-B IN.
That way, Airservices is under less pressure to provide better or more services, ATSB continues to get all the data to help explain, in three dimensional graphic detail, the track to the smoking hole and AMSA continues to get all the data to better “affect” - I think the correct word in the context of ATSB’s statement is “effect” - a rescue if anyone survives. Meanwhile, the aviation safety and airspace regulator – CASA keeps its lips pursed and avoids eye contact. A new cockpit gizmo, subsidised by someone else, is an excellent solution for all the agencies concerned. Pats on the back all round!
VFR pilots should make no mistake: Our biggest risk - aside from inadvertent entry into IMC or fuel exhaustion or starvation - arises from being ‘heads down’ in the cockpit rather than keeping a proper lookout. There are of course visibility limitations created by airframe structures of every aircraft and the relative locations of other aircraft in flight. But it’s certain a pilot’s not going to see anything anywhere outside the aircraft while ever the pilot’s focusing on a gizmo in the cockpit and making the assumption it’s a source of traffic truth.
Assumptions about the absence of conflicting returns on a ADS-B IN system display and silence on the radio can lead to a dangerous false sense of safety. Just as there are plenty of explanations for silence on the radio, only one of which is the absence of other aircraft in the vicinity, there are plenty of explanations for no ADS-B IN system returns, or inaccurate information, on an ADS-B IN display. (Most of the traffic based at my local aerodrome involves aircraft that have no ADS or SSR transponder - at least none that’s switched on - whose pilots are best described as ‘taciturn’.)
There are plenty of examples of VFR pilots seeing an ADS-B IN return on their EFB and using that information to see and avoid - or mutually arrange separation from - another aircraft. And there are plenty of examples of IFR aircraft seeing VFR ADS information and doing the same. And that’s a great outcome. But those pilots don’t know what traffic wasn’t displayed accurately or at all in their cockpits at the time. There is no guarantee that all traffic in the vicinity will ever be displayed by ADS-B IN systems. And as with any other aircraft system, you have to know what the specific ADS-B IN system you’re using can do, how to get it to do what it can do and how to confirm it's actually doing what you assume and hope it’s doing, and that means understanding the system’s failure modes.
For all those reasons and more, I consider this to be an overstatement by ATSB:There are lots of “ifs” missing from that sentence and the ATSB’s categorical “would have” conclusion. Both the Otter and Beaver in the Alaska tragedy were equipped with ADS-B IN but that didn’t result in either pilot comprehending the location of the other’s aircraft into which they collided.
The ATSB went on to say:Could have. If. Probably. The Beaver in the Alaska tragedy was carrying an EFB with a traffic alerting system. It didn’t work in the case of the Otter because the Otter was, unknown to its pilot and previous pilots, not broadcasting pressure altitude information. The Otter had traffic alerting capability, too. Until it was removed.
The equipment actually fitted to the Mangalore aircraft in compliance with regulatory requirements actually ‘triggered’ Short Term Conflict Alerts in the air navigation service system. Another description of those alerts is “advance warning of a potential collision”. That’s the verypurpose of STCAs. And the pilots of the aircraft probably assumed – reasonably I would suggest, given all of the safety hype around the original ADS-B mandate – that the air navigation service system would pass on those warnings rather than being justified in unilaterally dismissing them. Perhaps the tragic accident would have also been avoided if IFR pilots had clearly understood what a dangerously invalid assumption they were making about what the new ADS-B system was going to do for them.
On the subject of cockpit gizmos, there is one which is very cheap, very reliable, very accurate and almost pilot-proof: A modern carbon monoxide detector.
I mention carbon monoxide detectors because of the NSW Coroner’s Court inquiry and findings in the wake of the tragedy in which seven lives were lost in the Beaver accident at Jerusalem Bay in Sydney in 2017. One of the useful (and disturbing) things a modern CO detector will show you is the high level of CO to which we’re often exposed while just taxiing around on the ground (or water) in ‘ordinary’, serviceable aircraft. It will also help you to work out what to do with vents and windows to reduce the levels of exposure. Many of you will be blissfully unaware of the extent of your on-ground exposure and CASA remains wilfully blind to it, relying instead on reports from LAMES about defects found during maintenance and waiting for more CO exposure-caused fatalities and injuries.
In the course of the Coronial inquiry CASA was asked, in effect, how many more fatalities it would take before CO detectors would be mandated. According the Coroner, the CASA witness “frankly acknowledged”:Translation: Affordable safety. CASA has decided that the value of lives potentially saved by mandating CO detection equipment is not sufficient to justify the mandate.
The evidence given by CASA was to the effect that there are approximately 8,365 single piston engine aircraft in operation in Australia and that dash-mounted CO detectors cost about $1,200. (Let’s set aside the fact that there are much cheaper options that are just as reliable and accurate, and include aural and visual alerts, as some panel mounted versions – remember how long it took to get rid of the fixed ELT mandate and how long it took for EFBs to be accepted by the regulator?) On CASA’s figures that’s about $10,000,000 to fit the single piston engine fleet. So, that means CASA reckons it’s not worthwhile spending $10,000,000 on CO detectors until the further body count makes it worthwhile.
In contrast, to justify CASA’s regulatory response in the wake of the Angel Flight tragedies involving a total of six fatalities (one near Nhill in 2011 the other near Mt Gambier in 2017), Dr Aleck of CASA said:When asked by the Angel Flight CEO as to why CASA had chosen to by-pass the usual protocols for regulatory change, the then CEO of CASA said:Why was CASA “prospective” rather than waiting for more accidents in the Angel Flight case, by-passing the usual regulatory change process, but is waiting for more fatalities and injuries in the case of CO detectors? Answer: The capricious consequences of politics. Pressure was put on CASA by the federal government to be seen to do something in the case of Angel Flight and, sadly for the next victims of CO exposure, the Beaver tragedy barely raised a federal government eyebrow in the direction of CO detectors. That’s probably because of the time it took to work out that CO exposure was a factor in the tragedy.
Get ADS-B IN by all means. But don’t believe all the hype. It’s not a panacea for situational awareness or the intractable inadequacies in air navigation services and airspace arrangements.
Yours in aviation safety.
The aim of the ADS-B rebate for VFR aircraft is not – or at least it was not originally - to improve the situational awareness and safety of VFR pilots, though that may coincidentally be an outcome in some limited circumstances. Nor is the aim of the rebate to make ATSB’s and AMSA’s jobs easier, though that may also be a coincidental outcome.
The primary aim of the rebate was – and so far as I can tell, remains - to make VFR aircraft more conspicuous – electronically – to IFR aircraft and the air navigation services system, so as to reduce the risks to IFR aircraft. Now the focus appears to have shifted to ADS-B IN and its claimed safety benefits for both IFR and VFR aircraft, even though ADS-B IN was not originally mandated for IFR aircraft.
I suggest that the shift in focus is in substantial part due to intractable inadequacies in air navigation services and airspace arrangements. Hopefully the ATSB is keeping an expert eye on those issues?
I also suggest that the ATSB should be a little more circumspect in extolling the benefits of ADS-B IN, particularly for VFR aircraft. There are many ‘ifs’ in a sentence that can logically conclude with ATSB’s statement that ADS-B IN: “greatly improves a pilot’s situational awareness and enhances the safety of their flight.”
Those ‘ifs’ include: If the pilot knows what the specific ADS-B IN system being used can do; If the pilot knows how to get the system to do that; If the pilot knows the failure modes of the system; If the pilot knows how to and does confirm the system is actually doing what the pilot assumes and hopes it’s doing and, most importantly: If the pilot always bears in mind than an absence of ADS-B IN returns (and radio silence) is no guarantee of the absence of other aircraft in the vicinity.
These extracts from an NTSB recommendation dated 13 May 2022 neatly summarise the intersecting limitations of see-and-avoid and ADS-B systems, while highlighting that even the ‘biggest and best’ ADS-B IN systems with traffic information displays and visual and aural conflict alert capabilities are not a situational awareness panacea, especially when the systems are not doing what pilots incorrectly assume they are doing:We’re all aware of the limitations of ‘see and avoid’. But the mitigation for those limitations at least so far as VFR pilots are concerned is not to stare at the screen of a gizmo in the cockpit displaying ADS-B IN symbols, trying to work out what they mean. Most of the ADS returns displayed on my EFB come from aircraft in the flight levels and are, particularly when flying anywhere in the ‘J curve’, a distraction from the real job of a VFR pilot.
It is true that ADS-B and other systems enable Centre to alert aircraft even in G airspace - whether VFR or IFR - that they are in potential conflict. I hear it quite often on the Area frequency and am thankful that it happens. But it’s also true that Centre is only doing that for VFR on a ‘workload permitting’ basis and sometimes the workload does not permit the provision of that ‘nice-to-have’ service. Radio silence from Centre is therefore not conclusive of an absence of potentially conflicting traffic.
Just look at the Ballina SFIS - not a ‘nice-to-have’ but a ‘supposed-to-be-delivered’ service due to the traffic density and consequent collision risks in the area - to see what happens when the air navigation service provider has higher priorities. The SFIS is simply NOTAMed ‘no-can-do’. But the traffic density and consequent collision risks don’t go away. Perhaps the airspace classification and dimension arrangements in the Ballina area remain a substantial part of the safety problem, ATSB?
And then there’s the Mangalore tragedy in which the air navigation service provider’s equipment reliably and accurately tracked and displayed two ADS-B equipped IFR aircraft in G airspace to the point of their mid-air collision and four fatalities, generating four Short Term Conflict Alerts for ATC along the way to the collision. That was after the ADS-B mandate for IFR aircraft was justified on the basis that it would help prevent precisely what happened. This from the ATSB report on the tragedy:The equipment on the two IFR aircraft generated what the air navigation service system construed as “nuisance” alerts – “an alert which is correctly generated according to the defined STCA system parameters (rule set), but is considered operationally inappropriate by the controller” - discussed further in the ATSB report. Many people were – and remain – astonished and appalled at that outcome.
Many of those alerts would not be construed as “nuisances” and dismissed as such if they occurred in airspace with separation standards. But changing the airspace arrangements around places like Mangalore and Ballina and… would create “nuisances” of a different kind: The airspace regulator would have to make those changes and the air navigation service provider have to employ more controllers.
Problem: What to do to shift the focus away from inadequate air navigation services and airspace arrangements, so as not to upset that status quo, while doing something that seems to address the risk of another IFR/IFR mid-air collision?
Solution: Encourage everyone to get ADS-B IN.
That way, Airservices is under less pressure to provide better or more services, ATSB continues to get all the data to help explain, in three dimensional graphic detail, the track to the smoking hole and AMSA continues to get all the data to better “affect” - I think the correct word in the context of ATSB’s statement is “effect” - a rescue if anyone survives. Meanwhile, the aviation safety and airspace regulator – CASA keeps its lips pursed and avoids eye contact. A new cockpit gizmo, subsidised by someone else, is an excellent solution for all the agencies concerned. Pats on the back all round!
VFR pilots should make no mistake: Our biggest risk - aside from inadvertent entry into IMC or fuel exhaustion or starvation - arises from being ‘heads down’ in the cockpit rather than keeping a proper lookout. There are of course visibility limitations created by airframe structures of every aircraft and the relative locations of other aircraft in flight. But it’s certain a pilot’s not going to see anything anywhere outside the aircraft while ever the pilot’s focusing on a gizmo in the cockpit and making the assumption it’s a source of traffic truth.
Assumptions about the absence of conflicting returns on a ADS-B IN system display and silence on the radio can lead to a dangerous false sense of safety. Just as there are plenty of explanations for silence on the radio, only one of which is the absence of other aircraft in the vicinity, there are plenty of explanations for no ADS-B IN system returns, or inaccurate information, on an ADS-B IN display. (Most of the traffic based at my local aerodrome involves aircraft that have no ADS or SSR transponder - at least none that’s switched on - whose pilots are best described as ‘taciturn’.)
There are plenty of examples of VFR pilots seeing an ADS-B IN return on their EFB and using that information to see and avoid - or mutually arrange separation from - another aircraft. And there are plenty of examples of IFR aircraft seeing VFR ADS information and doing the same. And that’s a great outcome. But those pilots don’t know what traffic wasn’t displayed accurately or at all in their cockpits at the time. There is no guarantee that all traffic in the vicinity will ever be displayed by ADS-B IN systems. And as with any other aircraft system, you have to know what the specific ADS-B IN system you’re using can do, how to get it to do what it can do and how to confirm it's actually doing what you assume and hope it’s doing, and that means understanding the system’s failure modes.
For all those reasons and more, I consider this to be an overstatement by ATSB:There are lots of “ifs” missing from that sentence and the ATSB’s categorical “would have” conclusion. Both the Otter and Beaver in the Alaska tragedy were equipped with ADS-B IN but that didn’t result in either pilot comprehending the location of the other’s aircraft into which they collided.
The ATSB went on to say:Could have. If. Probably. The Beaver in the Alaska tragedy was carrying an EFB with a traffic alerting system. It didn’t work in the case of the Otter because the Otter was, unknown to its pilot and previous pilots, not broadcasting pressure altitude information. The Otter had traffic alerting capability, too. Until it was removed.
The equipment actually fitted to the Mangalore aircraft in compliance with regulatory requirements actually ‘triggered’ Short Term Conflict Alerts in the air navigation service system. Another description of those alerts is “advance warning of a potential collision”. That’s the verypurpose of STCAs. And the pilots of the aircraft probably assumed – reasonably I would suggest, given all of the safety hype around the original ADS-B mandate – that the air navigation service system would pass on those warnings rather than being justified in unilaterally dismissing them. Perhaps the tragic accident would have also been avoided if IFR pilots had clearly understood what a dangerously invalid assumption they were making about what the new ADS-B system was going to do for them.
On the subject of cockpit gizmos, there is one which is very cheap, very reliable, very accurate and almost pilot-proof: A modern carbon monoxide detector.
I mention carbon monoxide detectors because of the NSW Coroner’s Court inquiry and findings in the wake of the tragedy in which seven lives were lost in the Beaver accident at Jerusalem Bay in Sydney in 2017. One of the useful (and disturbing) things a modern CO detector will show you is the high level of CO to which we’re often exposed while just taxiing around on the ground (or water) in ‘ordinary’, serviceable aircraft. It will also help you to work out what to do with vents and windows to reduce the levels of exposure. Many of you will be blissfully unaware of the extent of your on-ground exposure and CASA remains wilfully blind to it, relying instead on reports from LAMES about defects found during maintenance and waiting for more CO exposure-caused fatalities and injuries.
In the course of the Coronial inquiry CASA was asked, in effect, how many more fatalities it would take before CO detectors would be mandated. According the Coroner, the CASA witness “frankly acknowledged”:Translation: Affordable safety. CASA has decided that the value of lives potentially saved by mandating CO detection equipment is not sufficient to justify the mandate.
The evidence given by CASA was to the effect that there are approximately 8,365 single piston engine aircraft in operation in Australia and that dash-mounted CO detectors cost about $1,200. (Let’s set aside the fact that there are much cheaper options that are just as reliable and accurate, and include aural and visual alerts, as some panel mounted versions – remember how long it took to get rid of the fixed ELT mandate and how long it took for EFBs to be accepted by the regulator?) On CASA’s figures that’s about $10,000,000 to fit the single piston engine fleet. So, that means CASA reckons it’s not worthwhile spending $10,000,000 on CO detectors until the further body count makes it worthwhile.
In contrast, to justify CASA’s regulatory response in the wake of the Angel Flight tragedies involving a total of six fatalities (one near Nhill in 2011 the other near Mt Gambier in 2017), Dr Aleck of CASA said:When asked by the Angel Flight CEO as to why CASA had chosen to by-pass the usual protocols for regulatory change, the then CEO of CASA said:Why was CASA “prospective” rather than waiting for more accidents in the Angel Flight case, by-passing the usual regulatory change process, but is waiting for more fatalities and injuries in the case of CO detectors? Answer: The capricious consequences of politics. Pressure was put on CASA by the federal government to be seen to do something in the case of Angel Flight and, sadly for the next victims of CO exposure, the Beaver tragedy barely raised a federal government eyebrow in the direction of CO detectors. That’s probably because of the time it took to work out that CO exposure was a factor in the tragedy.
Get ADS-B IN by all means. But don’t believe all the hype. It’s not a panacea for situational awareness or the intractable inadequacies in air navigation services and airspace arrangements.
Yours in aviation safety.
Just buy a Sentry. The top of the line model is less than 1/2 of the $1200 you quoted for a panel mounted CO detector, and it has a much better ADSB in and interface (as well as a recording g meter) than the couple of Stratii I’ve owned. Oh, and since Sentry pretty much invented home CO detectors, it’s the bomb among airborne CO alarms…
I put my sentry in other people’s aircraft when I’m flying with them (sticks to a window, does Bluetooth or Wifii. Likes to interface). and the number of burned out heater shrouds in singles (as well as two janitrol heaters which were within inspection dates, but had holes was amazing. Many of them had either chemical CO cards or actual electronic detectors, and none of them went positive below 150ppm
Thread Starter
The $1,200 I quoted came from a CASA witness at the Beaver coronial inquiry, and was in AUD including installation. But that's just for a panel mounted CO detector without any ADS functionality. That’s an awfully expensive CO detector even taking exchange rates into consideration.
A highly accurate, 'pocket' CO detector with aural and visual alerts and Bluetooth capability costs around AUD300. That’s AUD2.5 million rather than AUD10,000,000 for the entire piston engine fleet in Australia (based on the fleet size used in CASA’s calculation). And if the mandate applied only to aircraft carrying fare-paying passengers, that brings the overall 'fleet cost' down even further. It appears to me that CASA does not put a very high price on a fare paying passenger’s life.
Your mention of equipment, like Sentry, with ADS-B IN functionality and traffic alert functionality and accurate CO detection and alert functionality points up another strange aspect of the ATSB’s current focus. Out of the Jerusalem Bay Beaver tragedy, ATSB recommended that CO detectors be mandated! That was rejected by CASA. I would have thought that if ATSB considers ADS-B IN and CO detectors to be such great enhancements to safety, ATSB would be extolling the virtues of the available ADS-B IN systems that include an accurate CO detector. (Does the Sentry WAAS GPS work here?)
(Those chemical CO cards change colour just after the pilot is sufficiently poisoned not to notice.)
A highly accurate, 'pocket' CO detector with aural and visual alerts and Bluetooth capability costs around AUD300. That’s AUD2.5 million rather than AUD10,000,000 for the entire piston engine fleet in Australia (based on the fleet size used in CASA’s calculation). And if the mandate applied only to aircraft carrying fare-paying passengers, that brings the overall 'fleet cost' down even further. It appears to me that CASA does not put a very high price on a fare paying passenger’s life.
Your mention of equipment, like Sentry, with ADS-B IN functionality and traffic alert functionality and accurate CO detection and alert functionality points up another strange aspect of the ATSB’s current focus. Out of the Jerusalem Bay Beaver tragedy, ATSB recommended that CO detectors be mandated! That was rejected by CASA. I would have thought that if ATSB considers ADS-B IN and CO detectors to be such great enhancements to safety, ATSB would be extolling the virtues of the available ADS-B IN systems that include an accurate CO detector. (Does the Sentry WAAS GPS work here?)
(Those chemical CO cards change colour just after the pilot is sufficiently poisoned not to notice.)
"Which of the displayed aircraft, if any, is a collision risk to me on my track WAD - TWRN? (This is just a snapshot from the EFB provider supplied data, without my conspicuity device connected. Just assume they are ADS-B IN symbols in green.) You have the luxury of looking at a much bigger and stable display on your computer monitor."
Why isn't that interface also showing automobile traffic and Zillow prices?
It can project expected path but not filter for altitude? Sucky software sucks.
Per the mid-air followup, the alarms didn't go off because there was no pressure altitude to one ADSB-Out. Why was there no continuous alarm in that plane indicating a critical failure? Why no horizontal separation alert on either plane? Why not also use GPS geodetic altitude as well as pressure altitude? Sucky software and sucky specification sucks.
Why isn't that interface also showing automobile traffic and Zillow prices?
It can project expected path but not filter for altitude? Sucky software sucks.
Per the mid-air followup, the alarms didn't go off because there was no pressure altitude to one ADSB-Out. Why was there no continuous alarm in that plane indicating a critical failure? Why no horizontal separation alert on either plane? Why not also use GPS geodetic altitude as well as pressure altitude? Sucky software and sucky specification sucks.
Thread Starter
That's why the adverts from ATSB should include one of those really quickly read disclaimers at the end:
"Your ADS-B will be sucky unless...."
My version of that disclaimer is all of the 'ifs' I've explained earlier.
"Your ADS-B will be sucky unless...."
My version of that disclaimer is all of the 'ifs' I've explained earlier.
In mid-October 2023, a Sling light sport aircraft and a Piper Cherokee operating in the Moorabbin training area, south-east of Melbourne came within 100 metres of each other while both aircraft were flying at the same altitude.
ADSB-IN won’t help all that much in the training area as there are too many turns being made and it’s almost impossible to tell which way the other aircraft is heading without staring at the ipad for 20+ seconds at a time.
I’m not a fan of the 4G ADSB-IN traffic because it’s too latent… you really need a SkyEcho or similar for the direct source of truth. In fact I might made a YouTube video to highlight the difference.
I suppose the problem is integrating flight-navigation software with situation awareness software. I expect the nav software guys add it because, for them, it's cheap and they don't care.
This looks as I would expect a traffic display to look:
http://www.nexairavionics.com/wp-con...c-Display-.jpg
or
http://www.nexairavionics.com/wp-con...04-04_G-58.jpg
This looks as I would expect a traffic display to look:
http://www.nexairavionics.com/wp-con...c-Display-.jpg
or
http://www.nexairavionics.com/wp-con...04-04_G-58.jpg
The little green lines are handy for predicting their direction, however the training area is so small and there are so many manoeuvres being made that you couldn’t keep track very easily.
Even if there were proximity alerts in your EFB with audible alarms, you wouldn’t know from direction the other aircraft was, because you may both be turning.
I know FLARM has a complex algorithm for this, however I wonder how the gliding guys deal with it… I guess they west a parachute for this reason ! (Amongst others)
Even if there were proximity alerts in your EFB with audible alarms, you wouldn’t know from direction the other aircraft was, because you may both be turning.
I know FLARM has a complex algorithm for this, however I wonder how the gliding guys deal with it… I guess they west a parachute for this reason ! (Amongst others)
Thread Starter
Exactly, Squawk.
The ATSB has used a bad example in its recent advert. VFR aircraft in a published flying training Delta.
One need only watch what goes on (and to have been in there doing it) to know why ATSB should be very circumspect in plugging ADS-B IN as a useful tool for collision avoidance for VFR aircraft in training areas. If all you have is a screen in the cockpit displaying the 'raw' ADS aircraft symbols and data, you'll go crazy staring at that display trying to keep track of where everyone is now and going next. And if you have all the traffic alerting 'bells and whistles', they'll send you crazy too. (I now leave my CO detector off before take off, for analogous reasons. Once in the air I'll soon see whether the CO level is unusual.)
The ATSB has used a bad example in its recent advert. VFR aircraft in a published flying training Delta.
One need only watch what goes on (and to have been in there doing it) to know why ATSB should be very circumspect in plugging ADS-B IN as a useful tool for collision avoidance for VFR aircraft in training areas. If all you have is a screen in the cockpit displaying the 'raw' ADS aircraft symbols and data, you'll go crazy staring at that display trying to keep track of where everyone is now and going next. And if you have all the traffic alerting 'bells and whistles', they'll send you crazy too. (I now leave my CO detector off before take off, for analogous reasons. Once in the air I'll soon see whether the CO level is unusual.)