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Aviation => Pilot/Controller Forum => Topic started by: kaktak1 on July 12, 2010, 09:38:55 PM

Title: Saab 340 Equipment type
Post by: kaktak1 on July 12, 2010, 09:38:55 PM
Pardon if I'm posting in the wrong area, but a question concerning the SF34 equipment type. Mesaba files /G while Colgan files /A. This is no problem, assuming the equipment in Mesaba's Saab 340 aircraft are most likely updated with /G capability. However - what about Colgan pilots? For some reason, I cannot envision a Colgan flightcrew intercepting only VOR radials in order to track a particular airway or intersection. Here is a Colgan flightplan from LGA: MERIT HFD V229 GDM V106 MHT. The equipment type was /A. In theory, it would not be possible to proceed direct MERIT without first intercepting a particular radial. Anyone have insight on this?
Title: Re: Saab 340 Equipment type
Post by: Jason on July 13, 2010, 09:30:08 AM
LGA 2 DP notes:

NOTE: MERIT departures expect radar vectors to LGA-R055.

On departure, you would expect radar vectors to join the LGA 055 degree radial to proceed to MERIT (also known as V99 if you take a peek at the low altitude enroute chart).
Title: Re: Saab 340 Equipment type
Post by: rpd on July 13, 2010, 07:27:41 PM
Thats what they all did in the old days (not that long ago really).  The former NWA now DAL DC9's are the same.  They are just RVSM certified /A aircraft.
Title: Re: Saab 340 Equipment type
Post by: cessna157 on July 28, 2010, 08:30:17 AM
You actually just asked a question that has some the possibility for some very deep and intricate answers.

But we'll try to keep it simple.  Disclaimer: the details have been dumbed down here for discussion/simplicity

First, let's get 2 quick defintions out of the way. 
An "intersection" is a fix that is defined by an intersection of 2 identifiable courses, or 1 course and a DME.
A "waypoint" is a fix that is defined purely by lattitude/longitude points, and not crossing courses (used with GPS).

MERIT is an intersection defined by the following (per the LGA2.MERIT departure):
LGA R055, 49 DME
CMK R085, 21 DME
HTO R320, 46 DME
MAD R295, 21 DME

So legally you can intercept any of these radials, and when you cross another one of the radials, or cross the DME distance, you are at MERIT.  As our good leader Jason described, the LGA2 departure says if you cannot proceed direct to MERIT, you'll be given a clearance to intercept the LGA radial.

I must admit this caught me off guard once.  We have full RNAV capability, and our FMS doesn't mention anything about intercepting a radial, it just has us expecting a direct-to clearance.  I was once given the intercept radial clearance and wasn't exactly ready for it.  OOPS!
Title: Re: Saab 340 Equipment type
Post by: davolijj on August 14, 2010, 12:32:50 AM
Sorry to bring up an old thread but Cessna157s reply got me thinking about something...

A friend of mine who flies an E170 told me that one of the most tedious things to program the FMS to do is to intercept a radial or join an airway, especially when they're not expecting it.  Certain SIDS or DPs call for this all the time but they may be embedded under a "via radar vectors as filed" instruction.  Here's an example (

However often times due to facility directives, LOAs, stuctured airspace, etc., the controller will have aircraft join a radial in lieu of a vector when the next controller will clear the aircraft on course.  An example I see in Memphis would be an approach controller issuing, "DAL2322 fly heading 250, intercept the MEM275 radial, contact memphis center."  The ZME controller would then clear the aircraft to the next filed fix.

So I guess my question is, is it really a cumbersome task on all aircraft to intercept a radial or join an airway?
Title: Re: Saab 340 Equipment type
Post by: atcman23 on August 14, 2010, 07:56:15 AM
With all the technology these days and RNAV becoming so popular, pilots like to hear "proceed direct <fix>"  instead of intercepting a radial.  At CLE, we have an E145 that comes in and files as a /W (they cannot proceed direct to an intersection) so the FDIO prints out a PDR that contains the radials that make up the intersections.  When you read the clearance to the pilot they have no clue what you're saying.  Really not that hard to intercept a radial...
Title: Re: Saab 340 Equipment type
Post by: Jason on August 15, 2010, 10:11:09 AM
So I guess my question is, is it really a cumbersome task on all aircraft to intercept a radial or join an airway?


It depends on the box you're using. Some are easier than others to do said task.  I find quite often that with the newer technology it is more difficult to complete some of the very basic functions like intercepting a radial, etc. since point to point navigation is what it's really designed to do.  Often times it's easier to skip the box and use the older technology (ie. tuning in and using a VOR as primary guidance) to intercept a radial.

Title: Re: Saab 340 Equipment type
Post by: cessna157 on August 16, 2010, 09:25:26 PM
Jason summed it up pretty well.

The FMS in my airplane can be easy and hard to use, depending on the situation.

If you need to intercept a radial outbound, and the fix is already built into your flight plan, then it's an easy 1-step process.  Same goes for intercepting a course inbound.  It can actually be done in 2 ways:

Outbound course:   Set the fix, then create a custom fix xxx miles out on the radial, then intercept the course in between.

Inbound course:  Set the fix, then program the radial to intercept.  This second way is how we set it up for all approaches:

Let's say we're shooting the ILS runway 18, that has a course of 184.  To clear up our screens, we will take one of the fixes on the approach, and program an intercept course of 184 (although we will actually intercept the actual localizer, unless we were shooting a GPS approach).

But the trick is when you have to intercept something that isn't already built in.  Then it might take a few steps.  At that point, it might just be easier to switch to radio navigation and intercept the course/radial...assuming you have the frequency handy.