MSAWS info?

[Mr Fishy]

Could any of you ATC guys give some information on minimum safe altitude warning systems. I believe this is a software program incorporated into a radar system to warn of an aircraft going below the msa. How wide spread around europe is this system in use? Is it used on airways radars over mountainous areas or is it only used with approach radar? Any info appreciated

[Mr Fishy]

not all at once now!!

[BEXIL160]

Okay, I'm up for it. . .. .I've never seen it in use in the UK at all. Can't speak for the rest of EUR.. .. .I believe that it is in widespread use in the USA, and I seem to recall that it was in use at Guam (Pacific) when a KAL B747(?) was attempting a ILS (NO GP) and got the altitudes wrong with fatal results I'm sorry to say.. .. .Any one else?. .. .rgds BEX

[BEXIL160]

Oh, I should add that the Guam MSAWS was allegedly switched OFF at the time due to a large number of false alerts.. .. .There is a Final Approach monitor in use at Gatwick (and Heathrow I think) which monitors horizontal displacement from the final approach track. Lots of fun when doing NDB approaches to 08R a few years ago.. . . .. .Rgds BEX

[spacer9969]

This system is used in Switzerland, within the approach sectors from Zurich and Geneva for IFR flights. It is not used in the Enroute Control. The system detects only the proximity of an aircraft with the ground, but not a "closing rate" like a normal GPWS does ! <img border="0" title="" alt="[Confused]" src="confused.gif" /> . .. .The system is divided in several aeras. Each of this area has a defined altitude, which is usely lower than the MSA and the minimum radar vectoring altitude. The remaining terrain clearance will be between 700 and 1000 ft. It works also on an ILS until about 2 miles final. If an aircraft goes below those defined altitudes, an oral warning "ALTITUDE" will be triggered and the altitude part of the radar-blip of the aircraft will change to RED. <img border="0" title="" alt="[Mad]" src="mad.gif" /> . .The controller has to acknoledge this alarm. The altitude will remain RED until the aircraft is above the minima's. <img border="0" title="" alt="[Smile]" src="smile.gif" /> . .. .It is, of course, possible to disactivate the system in case someone is doing a visual approach. <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" />

[Iron City]

The MSAW implemented in the US is in the ARTS terminal automation system. It is there because a TWA 707 hit a mountain on approach to IAD some years ago.. .. .The MSAW works by taking the target file information and comparing it to a grid of terrain elevations and obstructions. When the two get too close the MSAW activates a display blink and audio warning. It is not coupled in any way to the a/c radar altimeter or anything.. .. .Problems with it have been too many false alerts and the software must be maintained. Oft times it isn't, and since ARTS will be replaced by STARS any year now nobody wants to put the work into it.. .. .It was a KAL flight on Guam went into Nimitz Hill by the VOR. NTSB report has all kinds of details, not all pleasant.

[Scott Voigt]

You will also find an altitude alert in the eroute systems in the US, not just in the terminal environment. . .. .regards

[Euroc5175]

I have seen the system in use at Geneva. There is / was some R&D work being undertaken of MSAWS for the UK by the DAR folks at One Kemble Street. Not sure if this is still ongoing, or if it is another of the projects to have run out of funding?!?

[Spitoon]

Just found this. (http://www.caa.co.uk/docs/43/MSAW_PolicyPaperDraftA.pdf)