曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
50 miles out. If your arrival field is not served by ATIS, the same action will put you in
contact with an In-flight Weather Briefer.
Radar Contact ATC Basics
Version 4 December 2, 2007
Copyright JDT LLC 2005 Page 47
Destination Airport Served by Approach
On Low‟s frequency, you will likely get a pilot‟s discretion clearance – “descend at pilot‟s
discretion maintain (altitude). You can expect, I say again, expect a clearance to cross 40
miles from (fix) at (altitude) 250 knots”. This means you can stay at your current altitude for
the time being (or if descending, level off if you wish) but be prepared to get down.
Otherwise, you will not be in time for that crossing restriction. That restriction will not be a
request, folks.
If you are flying a jet, expect to be instructed to cross 40 miles from the destination airport at
either 11,000 or 12,000 (altitudes) with a possible speed restriction @250 kts. Turbo-Props
and Props can expect to cross 40 miles from the destination airport at 7000 feet and 4000 feet
respectively. Turbo-Props, do not forget to slow to 250 kts before descending below 10000.
Normal speed is fine for props. See “Near-side / Far-side Crossing Restrictions” section
below for further detail.
More discussion on discretion descent clearances, crossing restrictions, holding pattern, and
delay vector issues to follow.
Destination Airport not Served by Approach
Center/Tower/Ground – You will experience simple step descents, and no crossing
restrictions. At 60 miles from destination, Center will ask if you have the arrival weather, and
which approach you are planning on. Sub menus appear, making answering these questions
very easy. You will be handled with respect to your answers.
If at 60 miles you told Center you would like a visual, you can at anytime change your mind
and request a specific precision or non-precision, IAP approach. An IAP approach means you
fly “the full” approach with no assistance from the controller. RC does not tell you how to fly
an IAP approach. You will need those plates. Or, if at 60 miles you requested an IAP but see
the airport as you near the area, request a Visual.
Center only – You will experience simple step descents, and no crossing restrictions. You
can make an IAP approach request as early as 60 miles out if you wish, or hold out a bit while
you watch for the airport to come into view.
Do not forget that arrival weather as you get closer to your destination.
Pilot Discretion Descent Clearances
I have heard time and time again, “I was given some altitude, then I was told to cross X miles
at a different altitude. Does this mean I should wait until 40 miles out before descending? Do
I have to start down now? Which altitude do I descend to?” These are excellent questions.
Fact: Your most recently received control clearance supersedes all other clearances.
Example: You have been given “…PD to FL190”, then later the controller says “…descend
and maintain FL180”. FL180 is now your assigned altitude. FL190 is no longer of any
consequence, and “descend and maintain” means now. This is a totally different clearance
that negates the PD FL190 clearance. Again, your most recently received control clearance
supersedes all other clearances.
Radar Contact ATC Basics
Version 4 December 2, 2007
Copyright JDT LLC 2005 Page 48
We issue PD clearances because we are very aware of the cost benefits that “staying high”
yields (less fuel burned).
If you are told to “…descend at pilot‟s discretion maintain FL190…”, then later get “…cross
four zero miles from (fix) at 11,000 ft/250 kt…” FL190 is no longer in the picture. That is no
longer your assigned altitude. 11,000 is your assigned altitude.
Further, a crossing restriction is a pilot’s discretion descent clearance. This is very unlike a
“…descend and maintain…” altitude clearance where descent is required. What does that
mean to you? Given that a crossing restriction is a PD clearance, you are welcome to level off
at FL190 or any other altitude without fear of annoying the controller.
However, you need to plan whether to level off somewhere (optional), adjust your descent
rate, all respect to your speed, based on the requirement that you have to be at your newly
assigned altitude (in this case „one one thousand‟, or 11,000 ft), at or before whatever point
ATC gave you in the crossing restriction. This usually means 40 miles from your final
checkpoint. You have to be level at the assigned altitude, at or before reaching this point. If
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
航空资料15(84)
