Question about 'Transitions'

[McPlane 13]

I know of SIDS and STARS but Transitions confuse me.

Is a Transition the last waypoint of a SID and is a Transition the first waypoint of a STAR?

 

[Chock 17,769]

 

1 hour ago, McPlane said:

Is a Transition the last waypoint of a SID and is a Transition the first waypoint of a STAR?

Sort of. If you want the full SP, read this. But here's the short explanation of it which should help you understand how the system works.

A procedure where you use a SID to get off the ground and onto your route has three specific parts, the Runway Transition, the Common Route, and the En-Route Transition. The en-route transition is the bit most pilots, controllers (and your FMC) are normally referring to when the name 'transition' is used and it is the bit which joins the end of main SID route to the first waypoint of your flight plan. So...

The runway transition is the bit where you fly off the runway, climb to a specific altitude and turn to a specific heading, then you're on the common route part, which is typically a straight line away from the airport heading toward an airway junction point. Which SID you chose will dictate in which direction you are heading away from the airport on which common route. At the last waypoint of the common route, this is where you meet up with your selected transition, which is the bit you chose which joins up the end of the main SID procedure to the first point on your flight plan route, so that last common route waypoint is a bit like getting to a T junction of a road, where one transition you could have picked is equivalent to making a left turn and another transition you might have picked is the equivalent of making a right turn.

A STAR is basically the reverse of this procedure, used to get you off an airway to the airport and lined up with a runway.

Below is my top quality drawing to help you understand it all. In this example, if you are using runway 09L or 09R, and you want to fly a route either north or south, you pick the Lion SID (1 or 2 depending on which runway you are on), and then you add the North, or South transition to the end of the SID, so it joins up with the first waypoint of your route because your route's first waypoint starts on the High altitude Jet airway:

Edited August 8, 2020 by Chock

[richjb2 195]

Nice explanation, Alan!

Rich Boll

 

 

[McPlane 13]

Wow, thanks very much!

[LesOReilly 176]

19 hours ago, Chock said:

 

A STAR is basically the reverse of this procedure, used to get you off an airway to the airport and lined up with a runway.

Not to be Nit-picky .... The STAR does not align you with the Runway.  It connects you to an Approach and the Approach will align you with the runway......Unless it is a circling approach...which will get you into Visual contact below IMC and allowing for a Visual approach.

I was not able to find a way to send you a PM so please don't take this as a public showing of trying to be contradicting you and trying to seem smarter...

[McPlane 13]

No problem at all. I appreciate all input. Learning, learning and learning. You actually clearifed the Approach for me. Thanks.

[LesOReilly 176]

7 minutes ago, McPlane said:

No problem at all. I appreciate all input. Learning, learning and learning. You actually clearifed the Approach for me. Thanks.

While my clarification of the reply point was to help complete the post my comment was directed to Chock as I was essentially "correcting" a small word change from Runway to Approach.....But I don't think I am able to send him a PM as that would have been better....

[Chock 17,769]

Without writing a novel it is tricky to cover every point, which is why I linked to the pdf FAA guide which covers it all in more detail, then just wrote a quick n dirty version which gives the basics of the thing, along with a simple drawing, and this because after a few hours of no replies, nobody had stepped up to answer the question for the OP. So yeah, it ain’t the gospel, just the gist of it, which is why I wrote that a SATR is basically the reverse used to get you lined up, rather than saying that's exactly what it does.

So, kind of the jumping off point for anyone who wants to read up more about stuff, with a link to where that could be done.

Worth noting here too is that I linked to the US's FAA guide to that stuff. There are similar guides for airspace in other places around the world and some geographical differences are in place, but as a general guide that FAA one will do the trick.

Another thing to note if you do read up more on this, is that Transition is a word which also refers to the 'transition altitude' at which the altimeter is set from local to standard pressure, but it also differentiates the level at which  you can transition through controlled airspace without interfering with maneuvers below that altitude, so it too is related to the maneuvering of things in and out of airports. 

Edited August 9, 2020 by Chock

[mSparks 2,086]

also to say thanks all, this is really the more detail I was looking for when I posted

I knew there was something I was missing but couldn't work out what it was.

 

[bofhlusr 453]

On 8/9/2020 at 2:09 PM, Chock said:

...Transition is a word which also refers to the 'transition altitude' at which the altimeter is set from local to standard pressure, but it also differentiates the level at which you can transition through controlled airspace without interfering with maneuvers below that altitude, so it too is related to the maneuvering of things in and out of airports. 

Chock, where would one get detailed info on the 'transition altitude' worldwide.  Would you know if 13-18k feet applies to the metric world eg. USA vs UK, China, Russia, Nepal, etc. A similar question with regards to standard pressure. Is it 29.92 hg all over also? Just curious.

[787flyer 633]

I thought I would reply to this even though its been a long time since the last post and question.

 

Regarding a list of transition altitudes, a single list as far as I know does not exist or at least I could not find one on the internet. More importantly, while there is a generalization that each country has their own defined transition altitude, in some countries they can actually vary from one airport to another, such as the UK.  The best and most reliable way to find such info is on the navigation charts for each airport and associated SID/STAR.

With regard to setting altimeter to standard pressure at 29.92 or 1013mb, this is known as the pressure altitude. This specific altitude measurement relies upon a standard pressure setting being used as the reference point as compared to a relative or absolute height above ground (another reference point) and can be applied globally throughout the world. Everyone should be able to fly at this "standard altitude" assuming the measurement device in use has been calibrated correctly.