ASD-B IN – A different perspective on the recent hype
Thread Starter
Any of the newer avionics would have had PFDs lit up like a Christmas tree in this situation with audio alerts to match - providing there was indeed ADSB out. It seems that there was at best only one ADSB out here and even that is unclear.
I’ve flown behind IN/OUT for years and can attest that it’s extremely accurate and very functional in busy class D airspace . It’ll happily paint a dozen targets at a time all within a mile.
no need to have you’re head in the cockpit. It just calls them out.
Given the amount of pushback from industry just to introduce OUT, itll be ages before we get an IN/OUT mandate.
Maybe this incident will slowly move the needle.
I’ve flown behind IN/OUT for years and can attest that it’s extremely accurate and very functional in busy class D airspace . It’ll happily paint a dozen targets at a time all within a mile.
no need to have you’re head in the cockpit. It just calls them out.
Given the amount of pushback from industry just to introduce OUT, itll be ages before we get an IN/OUT mandate.
Maybe this incident will slowly move the needle.
It’s hard to summarize the functionality of it. The hazard avoidance section of the pilots guide runs 50pages. If you want the prioritization hierarchy give that a read.
Suffice to say if you get an aural alert and a big yellow tennis ball appearing on your PFD you know exactly where to look and avoid.
It has been known to alert over the top of landing clearances so there’s some angst about that.
AFAIK I must be connected to an unswitched audio to stop people turning it off (intentionally or unintentionally)
that Alaskan midair where everyone was equipped was some kind of configuration or installation error like that on one of the aircraft.
As I alluded to earlier even airline level TCAS is inhibited on approach and departure. At present the circuit area of an aerodrome is too chaotic for reliable solutions. TCAS/ACAS is great for en-route conflicts, but near airports its not going to do much but create a distraction of spurious alerts when you shpuld be heads outside monitoring your approach/flightpath and traffic, as well as a listening watch.
As I alluded to earlier even airline level TCAS is inhibited on approach and departure. At present the circuit area of an aerodrome is too chaotic for reliable solutions. TCAS/ACAS is great for en-route conflicts, but near airports its not going to do much but create a distraction of spurious alerts when you shpuld be heads outside monitoring your approach/flightpath and traffic, as well as a listening watch.
)
Thread Starter
Depending on the airport, some functionalities of TCAS are ‘inhibited’ by some crews on approach and departure. Some airports in the world are really, really busy. The content of 43’s post you quoted was probably an over-statement, but it’s not entirely inaccurate.
Depending on the airport, some functionalities of TCAS are ‘inhibited’ by some crews on approach and departure. Some airports in the world are really, really busy. The content of 43’s post you quoted was probably an over-statement, but it’s not entirely inaccurate.
I think it comes back to the idea that traffic displays are a technology you can use in advance to identify threats and initiate communication to avoid conflict via radio and see and avoid. Again in a busy circuit its a distraction that will not help much.
And it cant be stressed enough that transponders fail or can be turned off, then the target will be invisible to any traffic display or ACAS.
Of course, if the owner of the equipment fails to fix the kit...
B1352/23 REVIEW B994/23
RADAR COVERAGE, RADAR INFO SER AND RADAR BASED TRAFFIC INFO SER WEST
OF OAKEY (ROMA/GOONDIWINDI AREAS) NOT AVBL
DLA/RESTRICTIONS MAY OCCUR IN CTA
DUE OAKEY PSR/SSR FAILURE
FROM 09 110925 TO 11 220000 EST
RADAR COVERAGE, RADAR INFO SER AND RADAR BASED TRAFFIC INFO SER WEST
OF OAKEY (ROMA/GOONDIWINDI AREAS) NOT AVBL
DLA/RESTRICTIONS MAY OCCUR IN CTA
DUE OAKEY PSR/SSR FAILURE
FROM 09 110925 TO 11 220000 EST
When I posted the short initial comment regarding ADSB-IN / SeaWorld accident (post #43) I hadn’t anticipated the number and wide ranging contributions; so thank you for all your posts.
In my eyes the Sea World and Mangalore accidents are “bellwether” indicators of many of the issues / topics raised in many previous ATSB reports as well as the enormous number of posts on this and other aviation websites over the last 10 years.
I have been sent a copy of a technical paper (apparently available on the internet) that appears to be a production of two ATSB staff that was delivered to the ISASI conference in 2022.I believe it actually won an award for best paper at that conference. The paper under the name “From See and Avoid to Detect and Avoid” seems to be the basis for ATSB’s confidence and reasoning in their somewhat simplistic “marketing” for ADSB-IN for all VFR aircraft and the basis of this thread started by Clinton.
Some of the content also seems to be the source of graphical input in ATSB’s YouTube videos on the Mangalore accident, comparing the ground based TAAATS Eurocat STCA information with a prototyped ADSB-CDTI cockpit display.
An initial read of the paper and a review of the ATSB YouTube videos elicited the following doubts/issues:
1/. ATSB’s understanding of how the TAAATS Eurocat STCA functionality works and displayed is misleading, incorrect and definitely incomplete in the ATSB report and YouTube videos,
2/. ATSB’s ability to conduct proper investigations is severely hindered by their lack of knowledge and understanding of how TAAATS Eurocat works. A contributing factor to this is seemingly the lack of access to lossless video screen capture (TAAATS Eurocat Main/Auxiliary displays) coupled with synchronised air/ground and ground/ground audio. Evidence to be detailed in subsequent posts.
3/. Some of the concepts and graphical prototypes in the paper appear to have similarities in concept to an ADSB-IN cockpit product as described by BRONTË EXPERIMENTAL as per post # 72, as well as TCAS / ACAS general cockpit concepts.
4/. Some comments in the paper relevant to an investigation didn’t seem to be in the ATSB report, I will have to do a forensic examination of both.
More to follow…
In my eyes the Sea World and Mangalore accidents are “bellwether” indicators of many of the issues / topics raised in many previous ATSB reports as well as the enormous number of posts on this and other aviation websites over the last 10 years.
I have been sent a copy of a technical paper (apparently available on the internet) that appears to be a production of two ATSB staff that was delivered to the ISASI conference in 2022.I believe it actually won an award for best paper at that conference. The paper under the name “From See and Avoid to Detect and Avoid” seems to be the basis for ATSB’s confidence and reasoning in their somewhat simplistic “marketing” for ADSB-IN for all VFR aircraft and the basis of this thread started by Clinton.
Some of the content also seems to be the source of graphical input in ATSB’s YouTube videos on the Mangalore accident, comparing the ground based TAAATS Eurocat STCA information with a prototyped ADSB-CDTI cockpit display.
An initial read of the paper and a review of the ATSB YouTube videos elicited the following doubts/issues:
1/. ATSB’s understanding of how the TAAATS Eurocat STCA functionality works and displayed is misleading, incorrect and definitely incomplete in the ATSB report and YouTube videos,
2/. ATSB’s ability to conduct proper investigations is severely hindered by their lack of knowledge and understanding of how TAAATS Eurocat works. A contributing factor to this is seemingly the lack of access to lossless video screen capture (TAAATS Eurocat Main/Auxiliary displays) coupled with synchronised air/ground and ground/ground audio. Evidence to be detailed in subsequent posts.
3/. Some of the concepts and graphical prototypes in the paper appear to have similarities in concept to an ADSB-IN cockpit product as described by BRONTË EXPERIMENTAL as per post # 72, as well as TCAS / ACAS general cockpit concepts.
4/. Some comments in the paper relevant to an investigation didn’t seem to be in the ATSB report, I will have to do a forensic examination of both.
More to follow…
Thread Starter
I’ve been trying to get my head around the implications of your latest post and your post at #31 ER BN. My ‘take’ is that you have deep expertise in the area and you have no confidence that what’s presented in the ATSB report on the Mangalore tragedy is an accurate representation of what really happened or what the controller saw in relation to SCTAs. It my take correct?
Notwithstanding that I have no expertise in the specific ATC system displays and functionalities, it makes no sense to me that ATSB went to the trouble of recreating what ATSB represents as the display showing the velocity vectors as not intersecting at the time of what the ATSB describes as the 1122:49 STCA but decided not to recreate the display showing the velocity vectors at the time of what ATSB describes as the ‘final STCA’ at 1123:51 - immediately preceding the collision.
Notwithstanding that I have no expertise in the specific ATC system displays and functionalities, it makes no sense to me that ATSB went to the trouble of recreating what ATSB represents as the display showing the velocity vectors as not intersecting at the time of what the ATSB describes as the 1122:49 STCA but decided not to recreate the display showing the velocity vectors at the time of what ATSB describes as the ‘final STCA’ at 1123:51 - immediately preceding the collision.
Thread Starter
ATSB’s interim report of its ongoing investigation into the Sea World tragedy is already telling as to the limitations of anti-collision gizmos, particularly when they are not serviceable or are deliberately or unknowingly configured to filter out what are assumed to be ‘nuisances’. Key extracts, with my underlining:
While operating in NZ, the helicopter was fitted with an L3 Lynx NGT 9000D+ transponder with Automatic Dependent Surveillance–Broadcast (ADS-B)-out capability on 27 September 2022. At that point the unit appeared to function with recorded data matching records of flights undertaken in NZ up to 19 October 2022.
Details of the new registration were to be updated in the unit, and some problems doing so were encountered. For flights from 2 December 2022 to 26 December 2022, externally recorded ADSB data was either showing no data (4 days) or the old NZ registration (11 days). From 27 December 2022 the new Australian registration was recorded but all tracking within Australia was intermittent.
Additionally, on 20 December 2022 air traffic control at Gold Coast Airport could not identify XH9 on secondary surveillance radar. Following this, pilots were aware that they would not be accepted into controlled airspace in XH9 without a functioning transponder. Troubleshooting of the transponder was not complete at the time of the accident. During inspection of XH9 post-accident, the ATSB lowered the belly panel and found that the transponder antenna was disconnected.
…
The word “disconnected” is in an interesting one. It’s not one I would use if, for example, the antenna coax had been pulled out of the back of its fitted connector due to, for example, impact forces. I interpret it as meaning that the fitted connector remained on the antenna coax but it was not connected to the antenna. If that interpretation is correct, maybe the antenna had, in the course of fault finding or other maintenance, been deliberately disconnected and left disconnected, or not reconnected properly such that it vibrated loose and disconnected in subsequent operations.
I note that the installation manual for the L3 Lynx NGT 9000D+ system includes these CAUTIONS among others:
2. All antenna connections must be connected prior to operation.
My understanding is that the L-Band antenna is used to transmit/receive, among other frequencies, 1090 mHz – the frequency used for transponders and ADS-B in Australia. Happy to stand corrected. All of the avionics with transmitters that I’ve worked on could be damaged if they transmitted into the wrong impedance and, in any event, if no antenna’s connected the transmission doesn’t go far.
The L3 Lynx NGT 9000D+ also provided traffic advisory (TA) alerts. The unit could visually display traffic although this was not configured. In addition, the system was also not linked to another display, therefore it gave audible alerts only. Pilots would hear warnings such as ‘traffic, traffic, 3 o’clock high, 2 miles’.
There were two sensitivity levels, A and B. Sensitivity level A reduced the number of nuisance TAs during take-off and landing. Sensitivity level B maximised the detection of TAs during the cruise phase of flight. If the aircraft was at or below 1,700 ft above ground level (AGL), the traffic advisory system (TAS) would not display or calculate alerts for other aircraft which were determined to be on ground (not airborne). Intruders determined to be below 380 ft AGL were considered to be on ground.
A configuration option called ‘Ground Filtering Altitude’ allowed the user to set the on ground (alternate) determination for 5 ft instead of 380 ft AGL.
At the time of publishing, the exact settings of this unit had not been determined and analysis is ongoing.
…
My interpretation of the ATSB’s language here is that the TA alerting system was working in principle during the flight – “provided … alerts”; Pilots “would hear warnings” – and the only remaining question is whether the ‘ground filtering option’ was or was not configured such that XKQ would have a generated an alert. But I don’t see how the TA alerting system would have been working at all if XH9’s transponder antenna was disconnected. Again, happy to stand corrected if I’ve misconstrued ATSB’s language or misunderstand the technical consequences of XH9’s transponder antenna being disconnected.
(And I cannot help but point out the truly ghastly irony that these systems are deliberately designed and configurable to filter out the ‘nuisance’ of being warned about the very kinds of circumstances in which this collision occurred.)
…
XKQ was equipped with a Garmin GTX327 Transponder which was detectable by secondary surveillance radar and was detected on the day of the accident.
VH-XKQ detection equipment
The helicopter was fitted with an Avidyne TAS600 TAS. The system had a ground mode and a flight mode. It would automatically switch between the 2 as the aircraft climbed or descended through 400 ft. In flight mode, when a detected intruder met the criteria for TA, the system used an annunciator light (marked ‘Traffic’ or ‘Traffic Alert’) and an audible voice annunciation. The announced phrase was preceded by a tone and began as ‘Traffic’, the clock position of the alert was given, and then the relative altitude of the intruder and range was announced. It was reported that no annunciator light was present in XKQ.
When the host aircraft descended below 400 ft AGL, the system transitioned to ‘ground mode’ and TA announcements were muted. While XKQ was on the ground, the TAS600 would be in ground mode. Aural annunciations would be muted and the aircraft did not have an interface from the TAS system to a display. After departure on the accident flight, XKQ did not reach an altitude that would have triggered the TAS600 to switch to flight mode.
…
XKQ’s system was deliberately designed not to give an alert in the circumstances, even if XH9’s transponder had been working properly.
I look forward to seeing if the ATSB concludes that the much-hyped ADS-B IN functionality would have prevented this collision and terrible tragedy, and why.
VH-XH9 conspicuity devices
While operating in NZ, the helicopter was fitted with an L3 Lynx NGT 9000D+ transponder with Automatic Dependent Surveillance–Broadcast (ADS-B)-out capability on 27 September 2022. At that point the unit appeared to function with recorded data matching records of flights undertaken in NZ up to 19 October 2022.
Details of the new registration were to be updated in the unit, and some problems doing so were encountered. For flights from 2 December 2022 to 26 December 2022, externally recorded ADSB data was either showing no data (4 days) or the old NZ registration (11 days). From 27 December 2022 the new Australian registration was recorded but all tracking within Australia was intermittent.
Additionally, on 20 December 2022 air traffic control at Gold Coast Airport could not identify XH9 on secondary surveillance radar. Following this, pilots were aware that they would not be accepted into controlled airspace in XH9 without a functioning transponder. Troubleshooting of the transponder was not complete at the time of the accident. During inspection of XH9 post-accident, the ATSB lowered the belly panel and found that the transponder antenna was disconnected.
…
The word “disconnected” is in an interesting one. It’s not one I would use if, for example, the antenna coax had been pulled out of the back of its fitted connector due to, for example, impact forces. I interpret it as meaning that the fitted connector remained on the antenna coax but it was not connected to the antenna. If that interpretation is correct, maybe the antenna had, in the course of fault finding or other maintenance, been deliberately disconnected and left disconnected, or not reconnected properly such that it vibrated loose and disconnected in subsequent operations.
I note that the installation manual for the L3 Lynx NGT 9000D+ system includes these CAUTIONS among others:
1. Operating the unit with the GPS antenna connected and the L-Band antenna NOT connected may damage the unit.
2. All antenna connections must be connected prior to operation.
VH-XH9 detection equipment
The L3 Lynx NGT 9000D+ also provided traffic advisory (TA) alerts. The unit could visually display traffic although this was not configured. In addition, the system was also not linked to another display, therefore it gave audible alerts only. Pilots would hear warnings such as ‘traffic, traffic, 3 o’clock high, 2 miles’.
There were two sensitivity levels, A and B. Sensitivity level A reduced the number of nuisance TAs during take-off and landing. Sensitivity level B maximised the detection of TAs during the cruise phase of flight. If the aircraft was at or below 1,700 ft above ground level (AGL), the traffic advisory system (TAS) would not display or calculate alerts for other aircraft which were determined to be on ground (not airborne). Intruders determined to be below 380 ft AGL were considered to be on ground.
A configuration option called ‘Ground Filtering Altitude’ allowed the user to set the on ground (alternate) determination for 5 ft instead of 380 ft AGL.
At the time of publishing, the exact settings of this unit had not been determined and analysis is ongoing.
…
(And I cannot help but point out the truly ghastly irony that these systems are deliberately designed and configurable to filter out the ‘nuisance’ of being warned about the very kinds of circumstances in which this collision occurred.)
VH-XKQ conspicuity equipment
…
XKQ was equipped with a Garmin GTX327 Transponder which was detectable by secondary surveillance radar and was detected on the day of the accident.
VH-XKQ detection equipment
The helicopter was fitted with an Avidyne TAS600 TAS. The system had a ground mode and a flight mode. It would automatically switch between the 2 as the aircraft climbed or descended through 400 ft. In flight mode, when a detected intruder met the criteria for TA, the system used an annunciator light (marked ‘Traffic’ or ‘Traffic Alert’) and an audible voice annunciation. The announced phrase was preceded by a tone and began as ‘Traffic’, the clock position of the alert was given, and then the relative altitude of the intruder and range was announced. It was reported that no annunciator light was present in XKQ.
When the host aircraft descended below 400 ft AGL, the system transitioned to ‘ground mode’ and TA announcements were muted. While XKQ was on the ground, the TAS600 would be in ground mode. Aural annunciations would be muted and the aircraft did not have an interface from the TAS system to a display. After departure on the accident flight, XKQ did not reach an altitude that would have triggered the TAS600 to switch to flight mode.
…
I look forward to seeing if the ATSB concludes that the much-hyped ADS-B IN functionality would have prevented this collision and terrible tragedy, and why.
XH9s Lynx (even if its antenna was plugged in, turned on, its configuration appropriately done etc ) wouldn’t have detected XKQs transponder anyway as the GTX327 is Mode A/C/(maybe S) only not ADSB out.
If XKQs xpdr was an ADSB out then you would expect an appropriately installed, configured and tested Lynx in XH9 to have alerted.
There’s a litany of failures here with equipment installation and setup that’s only been very superficially covered in this report. When was the last transponder check? Other than the pilots working out it didn’t work or was flight IDing the last rego. Was the MR endorsed?
Most of these issues should have been an easy fix for any half competent avionics tech. It beggars belief that XH9 was flying around in commercial ops with the Hex not updated and/or just turned off and then had a “disconnected antenna”. I think there are some rules about that somewhere…
according to the report they still haven’t determined the status of the ground filtering altitude. Is the unit damaged? That’s 3 button presses.
it’s all moot anyway as XKQs avionics were never going to be of any use for ADSB.
ADSB IN/OUT is extremely powerful and having flown with it for many years in lots of busy airspace, I have no doubt that had both aircraft here been equipped with it then the outcome would have been different. The sad reality is that it’s going to be decades before there’s lots of IN unless it’s mandated.
Like I mentioned before, for me the real question here is what’s an appropriate amount of equipment (and inspection regime) for an operation that carries thousands of fare paying passengers a year? It’s less than what you need to fly IFR in private ops. That makes no sense to me.
I have to have a passenger warning that says my experimental doesn’t comply with the same safety standards as “normal passenger commercial flight”
Does the average passenger think that the sea world scenic is a “normal passenger commercial flight” (their interpretation- not CASAs) and has the same level of safety thereof?
If XKQs xpdr was an ADSB out then you would expect an appropriately installed, configured and tested Lynx in XH9 to have alerted.
There’s a litany of failures here with equipment installation and setup that’s only been very superficially covered in this report. When was the last transponder check? Other than the pilots working out it didn’t work or was flight IDing the last rego. Was the MR endorsed?
Most of these issues should have been an easy fix for any half competent avionics tech. It beggars belief that XH9 was flying around in commercial ops with the Hex not updated and/or just turned off and then had a “disconnected antenna”. I think there are some rules about that somewhere…
according to the report they still haven’t determined the status of the ground filtering altitude. Is the unit damaged? That’s 3 button presses.
it’s all moot anyway as XKQs avionics were never going to be of any use for ADSB.
ADSB IN/OUT is extremely powerful and having flown with it for many years in lots of busy airspace, I have no doubt that had both aircraft here been equipped with it then the outcome would have been different. The sad reality is that it’s going to be decades before there’s lots of IN unless it’s mandated.
Like I mentioned before, for me the real question here is what’s an appropriate amount of equipment (and inspection regime) for an operation that carries thousands of fare paying passengers a year? It’s less than what you need to fly IFR in private ops. That makes no sense to me.
I have to have a passenger warning that says my experimental doesn’t comply with the same safety standards as “normal passenger commercial flight”
Does the average passenger think that the sea world scenic is a “normal passenger commercial flight” (their interpretation- not CASAs) and has the same level of safety thereof?
Thread Starter
There is no configuration in my setup (Garmin) for excluding alerts based on any arbitrary altitude.
Im experimental so I can turn them off entirely if I like. I choose to leave them on.
What I can say from experience is the following things do alert:
If I’m on base and there’s someone on base on the parallel runway, that’ll alert. I couldn’t be precise about altitude in that case. That’s unlikely to be sub 400’ tho.
If there’s a crossing chopper low at mid field - which is very common and has had more than one near miss - that’ll alert. I dont know what altitude they are at, but I’m on the ground at flying speed or close too it airborne and climbing at 500-1000fpm.
A common one is me just after rotation with a trainer in the southern circuit on upwind. I’m definitely sub 400’ there - but with a high closure rate.
What doesn’t alert is me on short final with a stationary aircraft at the holding point. though they are painted brown for ground.
likewise - final for center with a plane on each side. That is rare though.
All of the ADSB OUT equipped aircraft are most definitely painted on the MFD (and PFD in synthetic vision if in front) regardless of whether the system determines they are worthy of auraly alerting or not.
A general observation is that it’s a pretty conservative setup. In jurisdiction(s) where installation rates are somewhat higher there are complaints about this.
Slight off topic but relevant. TCAS direct interrogation of mode C is obviously very outdated technology with lots of limitations. This is where all of the altitude based muting and the like comes from. In helicopters it’s particularly acute as they can change heading rapidly while potentially not changing course. This has made latency and extra sensors and as a worst case suppression important variables.
ADSB alleviates the vast majority of these concerns. it’s trivial for the boxes to determine the probability of aircraft being in proximity in the future.
To bring this back to the original thread conjecture.
The sad reality of ATC in this country is a bloated ineffective infrastructure that is literally decades behind the state of the art in many ways. The mangalore accident is an absolute tragedy. Most can read through the obfuscation and weasel words to get to the underlying human error.
The regulator clearly knows this but will never explicitly state it.
Regardless of what the controller told me (or didn’t) if I had repeated STCA equivalent on my ADSB IN (noise in my headset and a big tennis ball on my PFD - CDTI in bureaucratic gobbledygook) I sure as **** would be unilaterally arranging my own separation pronto regardless of airspace classification.
Which is your point…
Last edited by BronteExperimental; 18th Jan 2024 at 10:52.
Thread Starter
My point was more that your categorical statement that "had both aircraft here been equipped with [ADS-B IN] then the outcome would have been different" should, I think, be tempered a bit with some qualifications: The equipment must be serviceable, the equipment must be configured to give alerts in these frequently low level and frequently close proximity helicopter operations and the pilots must be trained to know how the equipment works and not to ignore alerts.
My (inexpert) guess is that the number of alerts in those kinds of operations would quickly result in configuration selections to filter them out. That's why I look forward to seeing if the ATSB concludes that the much-hyped ADS-B IN functionality would have prevented this collision and terrible tragedy, and why.
My (inexpert) guess is that the number of alerts in those kinds of operations would quickly result in configuration selections to filter them out. That's why I look forward to seeing if the ATSB concludes that the much-hyped ADS-B IN functionality would have prevented this collision and terrible tragedy, and why.
I guess with them landing literally a stones throw from each other, it would need to be highly configurable, or you’d simply just have to turn it off.
The following users liked this post:
Thread Starter
That's what I figure.
"In helicopters it’s particularly acute as they can change heading rapidly while potentially not changing course."
If heading is derived from GPS the GPS has no idea the orientation of the fuselage relative to direction of travel.
If heading is derived from GPS the GPS has no idea the orientation of the fuselage relative to direction of travel.
Thread Starter
I think BE was there referring to potential collision info derived from Mode C data alone, which does not include GPS position and the calculation of position done by other equipment is 'less instantaneous' than with Mode S / ADS-B?
Yes I think we are on the same page.
ADSB doesn’t require heading information other than to orient an IN display - if there is one.
mode C based TCAS is a whole other animal.
heading sensors, directional antennas on the top and bottom of the aircraft, baro alt etc.
In helicopters this is more complex for many reasons.
for example the belly mounted directional antennas are useless near the ground or water - where helicopters are more likely to be found. Hence the inhibiting close to the ground due to spurious reflections.
It was good technology for the day. It’s been superseded. I doubt anyone would argue that point. Fitment and usage though…
ADSB doesn’t require heading information other than to orient an IN display - if there is one.
mode C based TCAS is a whole other animal.
heading sensors, directional antennas on the top and bottom of the aircraft, baro alt etc.
In helicopters this is more complex for many reasons.
for example the belly mounted directional antennas are useless near the ground or water - where helicopters are more likely to be found. Hence the inhibiting close to the ground due to spurious reflections.
It was good technology for the day. It’s been superseded. I doubt anyone would argue that point. Fitment and usage though…
