simonriat
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FMC, SIDs & STARs

Tue Jan 11, 2011 5:38 pm

Hi All

Sorry if this has been answered elsewhere, but just starting to get into what an FMC is capable of. And my intial thoughs are wow, what a powerful tool.

However I am rather confused.

Can anyone tell me, if SIDs and STARS for a particular flight are input into the FMC? Can it litrally fly you from the end of the departure runway to the threshold of the arrival runway?

How do requests from ATC effect this and can the FMC accomodate these changes?

Thank you for any replies as always much appreciated.

I can only dream of being a pilot, but it dosent stop me from wanting to learn as much as I poosibly can.

Regards
Simon
 
PGNCS
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RE: FMC, SIDs & STARs

Tue Jan 11, 2011 5:49 pm

The FMC (or FMGC if you are speaking Airbus) is a very powerful tool. The DP's and STARS's are selectable via the CDU/MCDU and when they are properly linked to your route a properly equipped aircraft can fly them from shortly after takeoff (engagement altitude varies between aircraft) and the approach. The aircraft would have to be put in the proper modes, of course (generally VNAV/LNAV, VNAV/NAV, or managed lateral and vertical navigation; there are also other terms depending on the aircraft type,) but as long as the aircraft is set up correctly, a highly automated flight can occur.

If ATC requests a change in the route we can select another DP or STAR or modify our route to go direct to any fix on the route or intercept a radial or course to a point on a route.

I hope this answers your general questions!  
 
tdscanuck
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RE: FMC, SIDs & STARs

Wed Jan 12, 2011 6:08 am

Quoting simonriat (Thread starter):
Can anyone tell me, if SIDs and STARS for a particular flight are input into the FMC?

Yep. On the off chance that ATC called out a SID/STAR that wasn't in the FMC navigation database, but you did have the chart, you could "hard code" it by inputting the individual waypoints with the relevant altitude/speed constraints. A SID/STAR is just a shortcut "copy-and-paste" mini-flight-plan that's a whole lot easier than having to give the whole SID/STAR every time you deliver a clearance.

Quoting simonriat (Thread starter):
Can it litrally fly you from the end of the departure runway to the threshold of the arrival runway?

Yes...appropriate button pushing is required of the pilots to engage the right autoflight modes at a few key pointss but, from autopilot engagement after liftoff, it's possible for the FMC (working with the autopilot and autothrottle) to fly the entire route to the final approach fix of the arrival runway. In an autoland capable aircraft, it can plant you on the runway and bring you to a full stop too (with autobrake and autospoiler too!).

Quoting simonriat (Thread starter):
How do requests from ATC effect this and can the FMC accomodate these changes?

Yes. The exact details of how you do it vary from FMC (to FMF to FMGC etc.) but, to expand on what PGNCS said, the FMC holds the flight plan as a series of legs from waypoint to waypoint (or along radials or arcs from navigation aids), some with altitude and speed constraints. The SID/STAR is just a "canned" set of waypoints/constraints. If ATC changes your STAR/SID, you just load the new one. If they take you off the STAR/SID, you just follow their guidance...that may be done via the FMC, or may be done by just using "dumb" autopilot modes like heading hold, altitude hold, vertical speed, etc. until ATC gives you the "proceed as filed" call or something like that, at which point you head to the next waypoint on your flightplan and turn it back over to the FMC.

For example, on a flight I flew today, we came in from eastern Washington and were cleared for the CHINS7 STAR (http:/flightaware.com/resources/airport/KBFI/STAR/all/pdf). At some point before we reached the entry point, they gave us direct-YAKIMA, so we deleted the first couple of waypoints and told the FMC to take us from wherever we were straight to YAKIMA (the rest of the STAR was still in the FMC). We followed the STAR us as far as AUBRN, where ATC gave us vectors around KSEA (fly heading BLAH, descent to BLAH, etc.) to pick up the Harbour Visual approach to KBFI 13R (http://flightaware.com/resources/airport/BFI/IAP/HARBOR VISUAL RWY 13R/pdf).

Since it was a visual, once we had the field in sight and ATC gave us the clear for the approach, we could navigate however we liked and didn't have to use the FMC. However, had it been a lousy day, they would have vectored us to the ILS intercept for KBFI 13R (http://flightaware.com/resources/airport/BFI/IAP/ILS+RWY+13R/pdf). From there, we'd arm autoland, it picks up the localizer and glideslope, and you're there.

Tom.
 
9V-SPJ
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RE: FMC, SIDs & STARs

Sat Jan 15, 2011 4:12 pm

There are also a lot of STARS which are now runway specific, i.e, once you select the enroute transition, you can also select the runway transition. This will lead you directly to the runway without having to program anything extra into the FMS.
A lot of STARS today do not have specific runway transitions to allow for flexibility in the TRACON and to change runway at a moments notice.

9V-SPJ
 
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zeke
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RE: FMC, SIDs & STARs

Sat Jan 15, 2011 5:40 pm

Quoting 9V-SPJ (Reply 3):
There are also a lot of STARS which are now runway specific, i.e, once you select the enroute transition, you can also select the runway transition. This will lead you directly to the runway without having to program anything extra into the FMS.

That does not make sense to me. I do not recall ever seeing a STAR associated with the actual runway, only to approaches procedures for a runway (even if it a visual approach).

The order things should be done ... for example SFO to YVR

Insert the start and end airports KSFO/CYVR
Insert the route between the airports - KSFO SFO RBL BTG J1 SEA PAE CYVR
Select the departure airport - KSFO
Select the departure runway - KSFO28R
Select the departure SID - REBAS 3
Select the transition on the SID to the route - RBL (RED BLUFF)
Select the arrival airport - CYVR
Select the arrival runway - CVVR26L
Select the arrival approach - ILS26L
Select the arrival STAR - PAINE ONE ARR
Select the arrival transition from the route to the STAR - PAE (PAINE)

This then links the departure from KSFO off runways KSFO28R to the REBAS 3 SID which links to the route RBL BTG J1 SEA PAE which links to the STAR PAINE ONE ARR which links to the ILS26L which joins the runway CVVR26L @ CYVR.

A STAR should take the aircraft to the IAF of an approach, not to the runway. In this example there is a flight plan discontinuity between the STAR and the ILS, as they expect radar vectors from the end of the STAR.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
airbuster
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RE: FMC, SIDs & STARs

Sat Jan 15, 2011 6:02 pm

And then the company can store so called "company routes" in the database so that we don't have to program all the airways separately, this is the flight plan route from the end of a specific SID to the beginning of a STAR. Company's often use several different routes to get to a destination so for example this morning from Nice to Amsterdam i could choose: NCEAMS01 NCEAMS02 or NCEAMS03, but off course today was a complete different route so we had to insert it ourselves.

The FMC let's you put in the airway numbers you'll be flying and then finds where they intersect by itself.

It really is a great tool in many ways.

rgds

AB
FLY FOKKER JET LINE!
 
9V-SPJ
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RE: FMC, SIDs & STARs

Sat Jan 15, 2011 6:38 pm

@ Zeke, there are some new STARS being trialed in the US, especially those which involve continuous descent arrivals being slowly introduced. One example is the VIKNN arrival into KATL. We (GATech, FAA, Delta etc), designed this arrival, when ATL is in east flow, to land on RW09R if I remember correctly.
One main reason advocating STARS having exact runway transitions, is to allow for greater use of TMA. It also reduces the amount of uncertainty in the different tactics controllers use to get an aircraft to the runway. If you are interested, I can email you a report on the design and flight test of CDAs into ATL.
There are a lot of drawbacks to having these kinds of procedures, namely not being able to sidestep as easily to other runways, but in the long run, along with all the other research being conducted, will more effectively deliver aircraft to the runway, maximizing capacity at the runway and various meter fixes along the STAR.

9V-SPJ
 
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zeke
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 4:16 am

Quoting 9V-SPJ (Reply 6):

Thats okay, I have been flying CDAs and RNAV SIDs and STARs for years. The STAR you mention does not take the aircraft to the runway, "expect radar vectors to final approach course".
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
IAHFLYR
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 3:46 pm

Quoting 9V-SPJ (Reply 3):
A lot of STARS today do not have specific runway transitions to allow for flexibility in the TRACON and to change runway at a moments notice.



Coding an approach transition however, does provide more flexibility to the pilot and controller for runway changes. IIRC the issue then is with criteria and having the same lateral path which in a busy terminal area is usually going to change as the downwind gets extended, then the controller will have to tell vector the arrival before they get to the turn point on the route. This added transmission to ensure the aircraft does NOT start the turn on base on the lateral track is not something a final controller should have to be concerned with while ensuring correct separation on final.
  
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9V-SPJ
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 3:55 pm

@ Zeke, the VIKNN ONE RNAV which was used in the flight tests we conducted in 2009 has the following wording:

'At VINII intercept and execute ILS or LOC Rwy 9R approach' so I guess it is sort of implying that it is a 9R arrival. If not, I stand corrected  

Out of curiosity, which CDAs have you flown? The EHAM and EGLL ones?

@ IAHFLYR, completely agree with you. Right now, there is a lot of research being done between the FAA and NASA and various contractors to try to enhance TMA at meter fixes and the runway to ensure that the lateral path remains consistent. Here is a link to some of the research I am working on:

http://www.aviationsystemsdivision.a...sa.gov/research/tactical/eda.shtml

9V-SPJ
 
IAHFLYR
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 4:08 pm

Quoting 9V-SPJ (Reply 9):
Right now, there is a lot of research being done between the FAA and NASA and various contractors to try to enhance TMA at meter fixes and the runway to ensure that the lateral path remains consistent.



Thanks for the link, I will take a look at it after posting my reply.

In order to keep the lateral path constant with what tools the controller has available today at the control position (none), the specific runway would only get arrival traffic from one arrival route. The sequence and separation would be established well outside the terminal airspace IMHO.
Any views shared are strictly my own and do not a represent those of any former employer.
 
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zeke
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 4:35 pm

Quoting 9V-SPJ (Reply 9):

'At VINII intercept and execute ILS or LOC Rwy 9R approach' so I guess it is sort of implying that it is a 9R arrival. If not, I stand corrected

That STAR is no longer current. It did not take you to the runway, it took you to the IAF for the approach.

Quoting 9V-SPJ (Reply 9):
Out of curiosity, which CDAs have you flown? The EHAM and EGLL ones?

Yes flown LHR, however most airports I fly to worldwide allow us to fly CDAs if the airspace allows, it is not a new concept. This is just another case of putting good airmanship on paper an calling it a new idea.

FYI going into SYD we let them know our TAS about 3-4 hours out so their computers can sequence the arrivals with minimum delays and level offs.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
9V-SPJ
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 5:34 pm

@ Zeke, yes I know, it has been withdrawn for sometime. It was only for the flight trials. Yes, CDAs are not that new, the big challenge is being able to predict altitude and speed profiles for a variety of aircraft, predicting the TOD (that is ground automation predicting the TOD), integrating it in a high traffic operations, and ATC verbage.

@ simonriat - sorry for hijacking your thread! Feel free to add any more questions!

9V-SPJ
 
IAHFLYR
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RE: FMC, SIDs & STARs

Sun Jan 16, 2011 5:46 pm

Quoting 9V-SPJ (Reply 12):
predicting the TOD (that is ground automation predicting the TOD),



Interesting, will your ground automation have the cost index downloaded from the aircraft?
Any views shared are strictly my own and do not a represent those of any former employer.
 
9V-SPJ
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RE: FMC, SIDs & STARs

Mon Jan 17, 2011 12:42 am

@ IAHFLYR - good question! Until ADS-B can downlink more data or the number of datalink parameters is expanded (let alone installed on a great portion of the fleet), we don't have anyway to get cost index or predicted weight at TOD. Right now, we are trying to figure out how to, procedurally, deal with the uncertainty in TOD. Right now, we are able to predict a TOD range for each flight, the question is, how big can this range be such that ATC does not have an issue with it.

9V-SPJ
 
IAHFLYR
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RE: FMC, SIDs & STARs

Mon Jan 17, 2011 3:20 pm

Quoting 9V-SPJ (Reply 14):
how big can this range be such that ATC does not have an issue with it.


You certainly can't have one set of parameters since crossing traffic below going into one airport will certainly be different from the next. I don't imagine some arrival routes having a TOD range of more than 5-10 NM depending on cruise altitude, while others may be able to accommodate slightly larger areas.

ADS-B equipage certainly won't go much faster than GPS equipage has, there are still a plethora of DME/DME/IRU airplanes flying around and having only a small number of ADS-B airplanes during an arrival bank will be a challenge.
Any views shared are strictly my own and do not a represent those of any former employer.

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