Again , thanks for the responses
anotherthing
I appreciate that a 'request heading' call might be misinterpreted . However , I would imagine that at this stage of the event , 'where to go' might not necessarily be the top priority to the Pilots : once the descent is well under way , however , some information gathering and analysis might be required ; and from this will come a decision as to whether to an immediate landing is actually needed or not . For Air supply or Pressurisation Control problems - or for damage confirmed to be minor - a crew may elect to continue to destination ( fuel , MSA permitting etc etc ).
( Many years ago we had a suddenly crazed windscreen at FL370 on the way somewhere .
Once the ED was complete at FL100 , we got the books out and discovered that the layer that had failed was not , apparently , critical to strength and that there was no restiction on Pressurisation load . We rather sheepishly climbed back up to FL370 for the rest of the Flight )
However , I can see how 'Request Heading' might be taken as a request for a vector to an Enroute . How about 'Request Heading for Separation' instead . If nothing else , it tells the Controller that the descending aircraft is able to take a vector if this is the simplest solution to ( multiple) Collision Avoidance .
78deg :
The extract from ICAO 7030 - which I must admit I am not familiar with - has the word 'proposal' in it as well as 'approved' : could you fill me in on the context of what this document is and what its regulatory status is .
I notice that point e) recommends using 'ACAS' to help collision avoidance . This unqualified advice is a bit at odds with the Eurocontrol 'ACAS Bulettin' linked on a previous post
Finally , yarrayarra , I have heard this before . While some pilots might elect to do this , IMHO it is all a bit unnecessary and overly dramatic . You have , after all , about 12-13 mins to get down to FL100 ( Pax O2 endurance) so even from FL410 you don't need an overall RoD of not much over 2500 fpm . Any delay in getting the descent going with a moderate - I would prefer the word 'controlled' - entry will result in a speed loss which will then allow a very high RoD while re-accelerting back to Target Speed , so it all works out about the same in the end . I agree that there is no time to hang around , but aggressivly banking to maintain positive g while initiating the descent is a bit OTT , in my view ( plus means taking the Autopilot out)