Go Back  PPRuNe Forums > Ground & Other Ops Forums > ATC Issues
Reload this Page >

Minimum Radar Vector Altitude protection?

Wikiposts
Search

Notices
ATC Issues A place where pilots may enter the 'lions den' that is Air Traffic Control in complete safety and find out the answers to all those obscure topics which you always wanted to know the answer to but were afraid to ask.

Minimum Radar Vector Altitude protection?

Thread Tools
 
Search this Thread
 
Old 20th December 2008 | 20:33
  #1 (permalink)  
Thread Starter
 
Joined: Oct 1999
Posts: 141
Likes: 3
From: United Kingdom
Minimum Radar Vector Altitude protection?

Simple question;

A transponding aircraft is subject to an approach control service and is generating a mode C return on the radar display. IF, for whatever reason, he descends below the minimum assignable radar vector altitude for his position, will there be any bells, lights, whistles or whatever generated by the radar hardware/software independent of any ATC intervention?

Thanks in advance.

Weary
Weary is offline  
Reply
Old 20th December 2008 | 22:30
  #2 (permalink)  
 
Joined: Oct 1999
Posts: 2,212
Likes: 0
From: Anywhere
No, not in the UK (though a mode 'C' driven system is in use in some parts of the USA - google "MSAW" for more info). ATCO monitoring mode 'C' is the order of the day.
Chilli Monster is offline  
Reply
Old 21st December 2008 | 11:57
  #3 (permalink)  
Thread Starter
 
Joined: Oct 1999
Posts: 141
Likes: 3
From: United Kingdom
Thanks Chilli

In a previous life (years ago.....) as an ATCO overseas, I recall having a conversation with someone from Thomson CSF about what was possible with radar technology as it moved increasingly toward computer interpreted and generated display hardware. This feature was mentioned as being possible - I was wondering if it had been realised anywhere.

Regards.
Weary is offline  
Reply
Old 21st December 2008 | 12:08
  #4 (permalink)  
 
Joined: Jul 2001
Posts: 311
Likes: 0
From: On a different Island
MSAW is active in Australian TMAs. But the CLAM alert (system monitoring of Cleared vs Actual Level) is always the first to be activated. Generally the MSAW goes off in error, or during the final approach phase (eg descending on the ILS) which makes it more or less useless. Various types of approach clearances or categories or flight or suppression areas also filter its effectiveness.

Last edited by Blockla; 21st December 2008 at 19:36.
Blockla is offline  
Reply
Old 21st December 2008 | 15:29
  #5 (permalink)  
 
Joined: Nov 2008
Posts: 179
Likes: 0
From: 5116N00044W
But if controllers can't be a***d to enter information such as cleared levels into the computer systems, there's nothing to compare the Mode C to!
PeltonLevel is offline  
Reply
Old 23rd December 2008 | 00:24
  #6 (permalink)  
Spitoon
Guest
 
Posts: n/a
From my limited experience every MSAW implementation has a high rate of false alerts and thus has limited value as a safety net. Route/Clearance adherence tools are workable in many en-route environments where flight data is maintained and transferred electronically as a matter of routine but are less practical in most approach environments - probably for the reason suggested by PeltonLevel as much as anything else.
 
Reply
Old 25th December 2008 | 15:44
  #7 (permalink)  
 
Joined: Jan 2008
Posts: 389
Likes: 0
From: Atlanta, GA, USA
Weary,

My favorite sector in Atlanta Center was the WILKES sector in western North Carolina (NW of KCLT.) It was really nothing more than an Approach Control in airspace that wasn't busy enough to justify having it's own Approach Control. It was 80 x 100 miles at 10,000 feet and below.

Anyway, at the Centers in the States we have MSAW -- Minimum Safe Altitude Warning. It is based on the MIA --- Minimum Instrument Altitude (which is slightly different than the Minimum Vectoring Altitudes used by Approach Controls.) If the aircraft descended below the MIA the datablock would blink on the scope. I think it was quite effective.

The alert could be surpressed and the parameters were locally adapted. Atlanta Center got its hand slapped when it was discovered that it had the MSAW suppressed within 50 miles of the destination. I think they changed it to suppress the alert within 10 miles of the destination airport.

Nuisance alerts could be a problem. An aircraft shooting practice approaches at an airport other than its destination could make you nuts. Between that and the Conflict Alert on VFR traffic, I've seen a half dozen data blocks flashing all at once. But all in all, I think it was a desirable feature.

Don Brown
GetTheFlick is offline  
Reply
Old 28th December 2008 | 20:29
  #8 (permalink)  
 
Joined: Mar 2008
Posts: 63
Likes: 0
From: In Denial
Hi Weary,
I feel your question has already been answered at length but here's my 2 cents:
At my station (Thales operated), the MSAW function is turned off, due to the large number of incorrect alarms. There are many situations here when an acft may decent below minimum radar terrain such as visual approaches. We tend to hold quite a bit of stock in the CLAMs (Clearance Limit Adherance Monitor). A lot less invasive (just a yellow block around the lable) and pretty effective, providing of course you keep your lables up to date...

No sirens or whistles, it just draws the ATCO's attention to it, we can then assess and react accordingly.
Skyjuggler is offline  
Reply
Old 5th January 2009 | 23:14
  #9 (permalink)  
Thread Starter
 
Joined: Oct 1999
Posts: 141
Likes: 3
From: United Kingdom
A late thanks chaps, for all the replies, but thanks nonetheless!
Weary is offline  
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.