Mode S is so popular in the Netherlands!

tnowak · Post by **tnowak** » Mon Apr 06, 2009 8:14 am

From our European correspondant (via a VPAC mailshot):
Quote:
"VFR traffic under the Schiphol TMA had been instructed to switch off transponders because of constant TCAS alerts, but recently the Dutch government decreed that all traffic above 800 feet should switch on Mode S everywhere. On the first sunny weekend following the decree Schiphol was swamped with a blizzard of Mode-S returns. ATC tuned the text size down to the minimum but still couldn't see approaching CAT clearly. All VFR traffic was banned from a huge swathe of airspace around Schiphol as a result. Ary Stiger of AOPA-Netherlands is meeting the Dutch CAA and Schiphol ATC on Tuesday to start sorting out the mess.

AOPA has ben warning for years that busy airspace would not bear the weight of Mode S, and controllers have said they would be forced to tune out Mode-S returns because of clutter (thus incidentally rendering the whole exercise futile for GA). For some reason Schiphol wasn't able to tune out Mode S when it happened, we don't know why yet.

The Schiphol issue was discussed today at the IAOPA-Europe regional meeting in Friedrichshafen. The UK CAA is aware of it, and has been preparing the ground for a couple of weeks for a change of heart on Mode-S; it is unlikely it will be adopted universally in the UK.

With effect from April 4th 2009
This AIP Supplement introduces the special rules zones Schiphol and Hilversum. These SRZs are created as a result of the radar clutter due to the increased number of VFR flights with activated mode S transponder under the Schiphol TMA 1. The radar clutter is increased to such an extent that Schiphol Approach cannot properly provide air traffic control. This radar clutter is a safety problem and is, therefore,not acceptable.
Dutch aviation authorities have therefore decided to clear the area around Schiphol, including Lelystad and Hilversum, from traffic with activated transponder. For Lelystad and Hilversum, a ‘transponder prohibited zone’ is created. Around Schiphol, a special rules zone (SRZ) is created. Aircraft with a mandatory mode S transponder are not allowed in this SRZ . "

Interesting!
Tony Nowak

Read more here http://www.ais-netherlands.nl/aim/misc/ ... 4-en-GBpdf

Mike Cross · Post by **Mike Cross** » Mon Apr 06, 2009 11:09 am

It gets even better.

There's also an AIC in force that says:-

The Ministry of Transport announces in cooperation with the Ministry of Defence that the exemption for the mandatory carriage of a SSR mode S transponder for motorised aircraft below the Schiphol TMA 1 is cancelled with effect from March 12th 2009. From that date motorised aircraft below the Schiphol TMA 1, executing a VFR flight above 1200 ft AMSL shall carry an active SSR mode S transponder. All aircraft with an operational SSR mode S transponder have to activate the transponder below the Schiphol TMA 1.

Since March 31st 2008, the use of a SSR mode S transponder is mandatory and the use of mode A/C transponder is prohibited.

Aircraft with an operational SSR mode S transponder have to activate the transponder in all types of airspace, even when it is not mandatory to use a transponder in that area.

All VFR flights with aircraft equipped with a SSR mode S transponder shall select code A7000, unless otherwise advised by ATC.

Operation of a transponder without mode C (flight level) is prohibited. Such a transponder will disturb the airborne collision avoidance functionality (ACAS) in public transport flights.

Aircraft equipped with a mode A/C transponder shall deactivate that transponder and have only access to airspace for which no mandatory carriage of a transponder is required.

This is one of the reasons why AOPA UK suggests that the proposed mandatory transponder usage beneath the Stansted CAS is not a good idea.

The other reason is that if Stansted want more protection they should provide a controller and make it Class D down to SFC with VFR traffic only in what is currently Class G. That way the controllers are in contact with a/c beneath the zone rather than just having a transponder return. The reason they won't like this is that it will cost them whereas mandating transponders does not.

Transponders put the cost on GA while doing little to deal with the problem. If they filter out the returns from below the base of CAS to avoid clutter they have insufficient time to take avoiding action against a 7000 squawk climbing through the base and no radio comms with the offender.

Making it Class D should not affect accessibility. The controller would not be required to provide separation (go read MATS Part 1) and would simple be providing clearances to VFR traffic in what is currently Class G. If someone is cleared "not above xxx feet" then he's more likely to stick to it.

Rod1 · Post by **Rod1** » Mon Apr 06, 2009 12:26 pm

Thanks Mike.

Is it AOPA’s position that the airspace be Class D and that aircraft flying in the area would have to have radio and mode C (at least)?

Rod1

John Price · Post by **John Price** » Mon Apr 06, 2009 12:34 pm

I don't think that enlarging controlled airspace will help. The crafty buggers will just say that they are too busy to grant a crossing clearence because of the quantity of CAT now using it. So all we will then have is less class G.

On a different tack,

Did anybody fly try to use Farnborough LARS on Sunday ?
I tried but found that they could only give a basic service at times due to controller overload, or unit working to capicity etc.
This is supposed to be the CAA/ NATS preffered option for a radar service to GA,in the south east, but if they cannot cope on a mild day in April what about when the summer rearly starts ?

Post by **John Dean** » Mon Apr 06, 2009 1:13 pm

Mike Cross wrote:Making it Class D should not affect accessibility.

I wish I believed that.

Mike Cross · Post by **Mike Cross** » Mon Apr 06, 2009 4:23 pm

.......... ah the difference between should not and does not

Still if people are determined to be bloody-minded I'll admit it's difficult to persuade them to change.

What would you prefer? No entry to N Weald if you don't have a transponder or the requirement to obtain a clearance? I suppose it depends on whether you have already forked out the cash or not.

David Corbett · Post by **David Corbett** » Wed Apr 08, 2009 7:18 pm

A number of LAA aircraft will visit Lelystad 9-12 May as part of the Flying Farmers Association visit to Holland and Norway. I am very concerned to read about the Mode S sitaution as reported in this thread, and even more concerned to be told by the CAA and by our Europa friends in Holland that all aircraft crossing the EHAA FIR boundary must be fitted with ELT.

Does any LAA member, or other reader, have actual experience of these two situations in 2009? Has anyone crossed into EHAA this year with PLB rather than ELT?

Many thanks,

David