Thanks Iz,
I ask because at Heathrow there is a low-level helicopter route that crosses underneath the 27R and 27L ILS. The route has a maximum level, which is separted from the traffic above, but it will be on another frequency, and often not squawking mode C. this usually results in a polite enquiry
about 'traffic on TCAS' which means replying with 'the traffic is following a published low-level helicopter route, promulgated at not above 1200 feet'. Then I have to phone down to the controller working the helicopter and get a confirmation of the helo's level and ask if it can squawk C.
Thanks again for your input.
Gonzo.
[This message has been edited by Gonzo (edited 05 May 2001).]