ATCPro Forums Homepage
Forum Home Forum Home > ATC Pro Forums > General Discussion
  New Posts New Posts RSS Feed - Speed Limit Below 10,000 MSL
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Speed Limit Below 10,000 MSL

 Post Reply Post Reply
Author
Message
MarkHargrove View Drop Down
Member
Member


Joined: 09 Jan 2016
Status: Offline
Points: 114
Post Options Post Options   Thanks (0) Thanks(0)   Quote MarkHargrove Quote  Post ReplyReply Direct Link To This Post Topic: Speed Limit Below 10,000 MSL
    Posted: 09 Jan 2016 at 8:30pm
Have a look at the airplane in the attached picture.  Why is the pilot flying at 290 kts?  Maximum speed limit below 10,000' MSL is 250 kts.




This was observed while watching an AI controlled session.  
Back to Top
helipilot7 View Drop Down
Newbie
Newbie


Joined: 07 Jan 2016
Location: Alberta, Canada
Status: Offline
Points: 2
Post Options Post Options   Thanks (0) Thanks(0)   Quote helipilot7 Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 8:44pm
Someone will jump in and correct me if I'm wrong, but that's going to be the aircraft's ground speed.  At 9,000' with an Indicated Air Speed of 250 kts and no wind, that aircraft is doing 290-295 True Air Speed, which is what you're seeing there.
NSDQ
Back to Top
Dave @ Flag Mountain View Drop Down
Admin Group
Admin Group


Joined: 09 Nov 2014
Location: Seattle WA
Status: Offline
Points: 159
Post Options Post Options   Thanks (0) Thanks(0)   Quote Dave @ Flag Mountain Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 8:54pm
Hi Mark,
Remember that the 250 kts speed restriction below 10000' is indicated airspeed in the cockpit of the aircraft. What we see on the datatag of the STARS scope is ground speed. Any wind component is added to the indicated airspeed that shows up as ground speed.

I find in ATCpro when I'm controlling arrivals in a tight pattern it is important to reduce all aircraft to the same airspeed, such as 180 kts, rather than expect them to do it automatically or assume that they will set their speed to something consistent. One way you can tell what the indicated airspeed is in the cockpit is to ask the pilot to "say speed".

In a similar manner, I usually give aircraft vectors to line up with the approach course rather than rely on and RNAV or localizer or ILS approach. It keeps me in control until I am sure the traffic is separated and on course.

Just my two cents,
Dave
ATCpro Project Team
Back to Top
mlovetto View Drop Down
Senior Member
Senior Member


Joined: 03 Jan 2016
Location: Alabama, USA.
Status: Offline
Points: 543
Post Options Post Options   Thanks (0) Thanks(0)   Quote mlovetto Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 9:39pm
Ground speed is on the scope. Ground speed is speed with wind. You're not seeing a true airspeed there.
Back to Top
Tom@FlagMountain View Drop Down
Admin Group
Admin Group


Joined: 22 Oct 2014
Location: Albuquerque, NM
Status: Offline
Points: 514
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom@FlagMountain Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 9:51pm
You can test this for yourself by issuing the command "<callsign> say speed".  Mlovetto is correct - the scope shows ground speed.
 
Regards
 
Tom
Tom Murdock
Flag Mountain Software
ATCpro Project Team
Back to Top
MarkHargrove View Drop Down
Member
Member


Joined: 09 Jan 2016
Status: Offline
Points: 114
Post Options Post Options   Thanks (0) Thanks(0)   Quote MarkHargrove Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 10:01pm
Sadly, while you're all certainly right, we cannot ask the pilot of this particular airplane what he was indicating.

Here was the situation a few minutes after my previous post (although the history trail is a little hard to see, the plane is flying a 220 heading).  Note the upcoming MVA.



And then a few minutes later:



...and then plane disappeared off the scope.    Dead

This was an AI controlled plane that came in from the east, was issued a 'report airport in sight', then 'enter right downwind for rwy 3'.  A couple of minutes after acknowledging that, the AI controller called 'Turn left heading 220' -- and never talked to the pilot again before his unfortunate collision with the terrain.

Thanks for the reminder about the datablock showing groundspeed -- I had indeed forgotten that.  :-)

-M.
Back to Top
mlovetto View Drop Down
Senior Member
Senior Member


Joined: 03 Jan 2016
Location: Alabama, USA.
Status: Offline
Points: 543
Post Options Post Options   Thanks (0) Thanks(0)   Quote mlovetto Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 10:04pm
He may have just dipped below radar coverage and is indeed still alive. The MVA is still 1000-2000 feet above the highest obstacle in that area depending on terrain. :-)
Back to Top
MarkHargrove View Drop Down
Member
Member


Joined: 09 Jan 2016
Status: Offline
Points: 114
Post Options Post Options   Thanks (0) Thanks(0)   Quote MarkHargrove Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 10:23pm
I hope you're right...but it wasn't until the plane was the next MVA segment (of 14.5) that it disappeared.  I fear the worst.   :-)

-M.
Back to Top
mlovetto View Drop Down
Senior Member
Senior Member


Joined: 03 Jan 2016
Location: Alabama, USA.
Status: Offline
Points: 543
Post Options Post Options   Thanks (0) Thanks(0)   Quote mlovetto Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2016 at 10:30pm
Lol
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.10
Copyright ©2001-2017 Web Wiz Ltd.

This page was generated in 0.141 seconds.