ARNAV ICDS 2000 update

Guest Discussion
1

All,

I emailed John Glaisyer of ARNAV Systems, Inc. to ask about the current status of the ICDS 2000 capabilities in the SR20. Below is his reply, which he graciously consented to let me post (Thanks, John).

"Here is the latest we have on other upgrades to the ICDS 2000:

"Our Terrain and obstruction application is standard on the ICDS 2000.

"The WX500 interface is available now.

"The engine monitoring should be available in your SR20 first quarter of 2001 and weather in the second quarter. I understand Cirrus will be making retrofit kits available if you take delivery of your SR20 before one of the above features is available.

"We should eventually support both the Ryan TCAD and B.F. Goodrich Skywatch, TCAD being first. The engineers at Cirrus are currently working to find locations for the antenna(s) for both systems. I don’t have an estimate on the time of availability for these two interfaces.

“We, at both ARNAV and Cirrus, are working hard to make all the features every customer is waiting for available with a minimum of inconvenience.”

As I didn’t know much about the Terrain and Obstruction application he mentioned, I asked him for more information. His response was clear and enlightening:

"The Terrain Obstruction Proximity System or “TOPS” is standard on all ICDS 2000’s and compares your GPS position and altitude from your mode C encoder with an elevation and obstruction database contained on the ICDS 2000 data card. It provides you with the highest obstruction within five (5) minutes flying time (based on your GPS ground speed)360 degrees around your

aircraft, “Look Around” and a 60 NM “Look Ahead”.

"The “Look Around” feature presents two lines of information in a box in the upper right hand corner of your display. The top line lists aircraft altitude (ALT) and the second, the elevation of the highest obstruction in the protected zone (OBS). In the event the aircraft is at or below the obstruction, the “OBS” information turns red and the elevation of the

obstruction on the moving map also turns red and an amber cross is put next to the obstruction.

"The “Look Ahead” window is displayed in the top center of the display and depicts a side view of the aircraft and compares the relative height of the aircraft to the terrain for a distance of 60 NM in front of the airplane (currently displayed in four 15 NM sectors, 4 NM’s either side of your

projected track). Once again, the ICDS compares your GPS position and altitude from your mode C encoder with the elevation and obstruction

database and if the elevation in any of the 8 by 15 NM sectors contains an elevation of obstruction within 500 feet of your altitude, that sector will turn to red, indicating a possible CFIT conflict."

Thanks again to John for this excellent description of this very useful function.

Mike.

2

All,

I emailed John Glaisyer of ARNAV Systems, Inc. to ask about the current status of the ICDS 2000 capabilities in the SR20. Below is his reply, which he graciously consented to let me post (Thanks, John).

"Here is the latest we have on other upgrades to the ICDS 2000:

"Our Terrain and obstruction application is standard on the ICDS 2000.

"The WX500 interface is available now.

"The engine monitoring should be available in your SR20 first quarter of 2001 and weather in the second quarter. I understand Cirrus will be making retrofit kits available if you take delivery of your SR20 before one of the above features is available.

"We should eventually support both the Ryan TCAD and B.F. Goodrich Skywatch, TCAD being first. The engineers at Cirrus are currently working to find locations for the antenna(s) for both systems. I don’t have an estimate on the time of availability for these two interfaces.

“We, at both ARNAV and Cirrus, are working hard to make all the features every customer is waiting for available with a minimum of inconvenience.”

As I didn’t know much about the Terrain and Obstruction application he mentioned, I asked him for more information. His response was clear and enlightening:

"The Terrain Obstruction Proximity System or “TOPS” is standard on all ICDS 2000’s and compares your GPS position and altitude from your mode C encoder with an elevation and obstruction database contained on the ICDS 2000 data card. It provides you with the highest obstruction within five (5) minutes flying time (based on your GPS ground speed)360 degrees around your

aircraft, “Look Around” and a 60 NM “Look Ahead”.

"The “Look Around” feature presents two lines of information in a box in the upper right hand corner of your display. The top line lists aircraft altitude (ALT) and the second, the elevation of the highest obstruction in the protected zone (OBS). In the event the aircraft is at or below the obstruction, the “OBS” information turns red and the elevation of the

obstruction on the moving map also turns red and an amber cross is put next to the obstruction.

"The “Look Ahead” window is displayed in the top center of the display and depicts a side view of the aircraft and compares the relative height of the aircraft to the terrain for a distance of 60 NM in front of the airplane (currently displayed in four 15 NM sectors, 4 NM’s either side of your

projected track). Once again, the ICDS compares your GPS position and altitude from your mode C encoder with the elevation and obstruction

database and if the elevation in any of the 8 by 15 NM sectors contains an elevation of obstruction within 500 feet of your altitude, that sector will turn to red, indicating a possible CFIT conflict."

Thanks again to John for this excellent description of this very useful function.

Mike.

Thanks for the encouraging notes on the ARNAV. Was there any discussion of engine monitoring functions?

3

"The Terrain Obstruction Proximity System or “TOPS” is standard on all ICDS 2000’s and compares your GPS position and altitude from your mode C encoder with an elevation and obstruction database contained on the ICDS 2000 data card. It provides you with the highest obstruction within five (5) minutes flying time (based on your GPS ground speed)360 degrees around your

aircraft, “Look Around” and a 60 NM “Look Ahead”.

"The “Look Around” feature presents two lines of information in a box in the upper right hand corner of your display. The top line lists aircraft altitude (ALT) and the second, the elevation of the highest obstruction in the protected zone (OBS). In the event the aircraft is at or below the obstruction, the “OBS” information turns red and the elevation of the

obstruction on the moving map also turns red and an amber cross is put next to the obstruction.

"The “Look Ahead” window is displayed in the top center of the display and depicts a side view of the aircraft and compares the relative height of the aircraft to the terrain for a distance of 60 NM in front of the airplane (currently displayed in four 15 NM sectors, 4 NM’s either side of your

projected track). Once again, the ICDS compares your GPS position and altitude from your mode C encoder with the elevation and obstruction

database and if the elevation in any of the 8 by 15 NM sectors contains an elevation of obstruction within 500 feet of your altitude, that sector will turn to red, indicating a possible CFIT conflict."

Mike,

Interestingly enough, the Wings Aloft/Cirrus SR20 Training Manual has this to say about the terrain warning features of the Arnav:

“The terrain/altitude feature is designed to warn the pilot of obstacles that may present a hazard. The display however can be very misleading. The obstruction heights displayed may represent obstacles behind the aircraft as well as ahead. More importantly, the altitude is GPS altitude [which differs from the mode C altitude that John mentioned to you] which may be inaccurate by 600 feet. Unless couples with a WAAS signal when available to allow for more accurate GPS altitudes, this feature should be used with suspicion or not at all.”

So I guess it remains to be seen whether is display is really useful… maybe some current owners can provide insight.

Steve

4

Thanks for the encouraging notes on the ARNAV. Was there any discussion of engine monitoring functions?

"The engine monitoring should be available in your SR20 first quarter of 2001 and weather in the second quarter.

Michael,

I did not discuss engine monitoring with John any further than the quote above. However, I have asked Cirrus for information about when this will be available, cost, etc. I’ll let you know what I learn.

  • Mike.
5

Mike,

Any idea of the cost of these features?

Dan

Thanks for the encouraging notes on the ARNAV. Was there any discussion of engine monitoring functions?

"The engine monitoring should be available in your SR20 first quarter of 2001 and weather in the second quarter.

Michael,

I did not discuss engine monitoring with John any further than the quote above. However, I have asked Cirrus for information about when this will be available, cost, etc. I’ll let you know what I learn.

  • Mike.
6

Mike,

Any idea of the cost of these features?

Dan

Dan,

No idea at all. I’ve asked - I’ll advise if I learn anything definitive.

Mike.

7

Interestingly enough, the Wings Aloft/Cirrus SR20 Training Manual has this to say about the terrain warning features of the Arnav:

“The terrain/altitude feature is designed to warn the pilot of obstacles that may present a hazard. The display however can be very misleading. The obstruction heights displayed may represent obstacles behind the aircraft as well as ahead. More importantly, the altitude is GPS altitude [which differs from the mode C altitude that John mentioned to you] which may be inaccurate by 600 feet. Unless couples with a WAAS signal when available to allow for more accurate GPS altitudes, this feature should be used with suspicion or not at all.”

So I guess it remains to be seen whether is display is really useful… maybe some current owners can provide insight.

Steve,

I was struck by the very different data: The Wings Aloft/Cirrus SR20 Training manual, which says that the altitude info is derived from the GPS, and the information I got from Arnav, which was that the altitude info comes from the Mode C.

So I asked John Glaisyer again, and he confirmed that it really is the Mode C.

My own feeling is that I’d rather be warned about terrain behind me that is no factor, than have a CFIT situation because of terrain I didn’t know about. Granted, we should all know about where we are and what the surrounding terrain is at all times, but reality is that we often do not, and I’ll take all the help I can get, especially when I’m flying low enough for it to matter.

Besides, for terrain behind me to be a factor, I figure that (at least most of the time) I have flown past it, so it was probably a factor in FRONT of me earlier. Also, what if I have to make an emergency descent to an airport behind me? That is an example of a time when once again, I’d be only too happy to have data like this available at a glance.

I echo your desire to get feedback from current users - is this TOPS feature useful, no factor, or what?

  • Mike.
8

I echo your desire to get feedback from current users - is this TOPS feature useful, no factor, or what?

Well, it might be useful if the database was accurate. I don’t know about the American database, but the International database is very inaccurate in its terrain heights - inaccurate in the wrong direction, i.e. it shows the terrain to be lower than it actually is.

Also, the readout gives the altitude as “GPS Altitude”, which is often higher than corrected pressure altitude. So I don’t find it useful.

9

Ditto for the European ARNAV database. I tend to ignore both terrain and airspace information, as I’ve found them to be inaccurate (as in “all Class C’s are a 5 mile radius around the main airport” simplification). Don’t understand why the terrain and/or airspace data cannot be derived from ONE source in the system, e.g. the Jepp card in the 430, that are by (my) definition current through the subscription…

Just my 2c worth from Europe.

HK (N144CD)

I echo your desire to get feedback from current users - is this TOPS feature useful, no factor, or what?

Well, it might be useful if the database was accurate. I don’t know about the American database, but the International database is very inaccurate in its terrain heights - inaccurate in the wrong direction, i.e. it shows the terrain to be lower than it actually is.

Also, the readout gives the altitude as “GPS Altitude”, which is often higher than corrected pressure altitude. So I don’t find it useful.