Jump to content

  •  


   
Where Flight Simulation Enthusiasts Gather from Around the World!

HOT SPOTS:
 rarrow.gif The 2014 Demographic Survey! - NEW!

rarrow.gif What's new in the Library

rarrow.gif Member Blogs

rarrow.gif Member Reviews - Contribute a Review!
rarrow.gif Bargain Hunters Forum
rarrow.gif Classified, Want, Swap Ads

rarrow.gif AVSIM Team Speak System

rarrow.gif Video Library
rarrow.gif Image Gallery
rarrow.gif Community Links Library
rarrow.gif Tutorials

rarrow.gif FS9. FSX & P3D CTD Guide

rarrow.gif FSX / P3D Configuration Guide

rarrow.gif AVSIM Publications 



Simulation's Premier Resource!

AVSIM is a free service to the flight and simulation communities. Please help us keep it that way. Donate what you can today! Thank you for your support!











. . .
Photo

ils approach do I press loc or app on mcp


  • Please log in to reply
51 replies to this topic

#1 moey124

moey124

    Member

  • Members
  • 133 posts
  • Joined 3 Years and 10 Days Ago.

Posted 08 September 2013 - 08:13 PM

Wel I clicked loc and the plane turned to the runway and when should I click app or loc is the same &@($* app on mcp. Cause my plane wasnt descending.
Mohit Mahtani

Help AVSIM continue to serve you!
Please donate today!

#2 AirKevin

AirKevin

    Captain Kevin

  • Members
  • 1,035 posts
  • Joined 5 Years, 7 Months and 19 Days Ago.

Posted 08 September 2013 - 08:24 PM

LOC is just the localizer. APP would be the actual approach, which you would press once the glideslope comes alive.


Captain Kevin
f4698d0c.jpg


#3 troyk

troyk

    Member

  • Banned
  • 165 posts
  • Joined 1 Year, 1 Month and 12 Days Ago.

Posted 08 September 2013 - 09:28 PM

Wel I clicked loc and the plane turned to the runway and when should I click app or loc is the same &@($* app on mcp. Cause my plane wasnt descending.

 

I'm only a novice but on an ILS approach I think you just need to press APP to pickup the glideslope. I am not pressing the LOC button at all. APP seems to capture both the localiser and glideslope.


Troy Krajancic


#4 captain420

captain420

    Member - 1,000+

  • Members
  • 1,295 posts
  • Joined 1 Year, 7 Months and 8 Days Ago.

Posted 08 September 2013 - 09:30 PM

Usually you would capture the localizer first, and then the gs. So 1st hit LOC and then APP after


Aaron Vinci


#5 AirKevin

AirKevin

    Captain Kevin

  • Members
  • 1,035 posts
  • Joined 5 Years, 7 Months and 19 Days Ago.

Posted 08 September 2013 - 09:30 PM

I'm only a novice but on an ILS approach I think you just need to press APP to pickup the glideslope. I am not pressing the LOC button at all. APP seems to capture both the localiser and glideslope.

Not all approaches are full ILS approach. There are some that are localizer only approaches, which is where the LOC button also comes in handy.


Captain Kevin
f4698d0c.jpg


#6 moey124

moey124

    Member

  • Topic Starter
  • Members
  • 133 posts
  • Joined 3 Years and 10 Days Ago.

Posted 08 September 2013 - 09:35 PM

But how do u know when u entrred the glidescope cause I hit loc and it truned to rjnway after passing one more star on the display I hit app but it didnt desend
Mohit Mahtani

#7 hopskip

hopskip

    Member - 2,000+

  • Members
  • 2,066 posts
  • Joined 12 Years, 3 Months and 21 Days Ago.

Posted 08 September 2013 - 09:37 PM

LOC will follow the Localizer. 

 

This is a system which transmits a radio beam of sorts that shows where the aircraft needs to track, and will cause the autopilot or flight director to command a correction - left or right - if it detects any deviation of the course from the radio beam's centreline (which at some places like Innsbruck or Kai Tak would be a radio transmitter on a hill somewhere, but at most airports would be a radio transmitter at the far end of the runway you are landing on).

 

APP mode follows both the localizer and the glideslope.

 

I repeat, LOC does NOT follow the glideslope.

 

The glideslope is like the Localizer, but it defines a descent path. If your autopilot is in APP mode, it will follow the descent path, and make corrections - up or down - if it detects any deviation of the glidepath defined by the radio beam's centreline (which at some places like London City EGLC is a 6.6° decent angle, but at most airports is closer to 3°.)

 

 

If you arrive at an airport ILS and press the LOC button, it will fly a track which flies directly over the runway centreline. It will maintain whatever altitude you have set on the Altitude Hold on the MCP.

 

so you will fly over the runway, dead on centre with the white lines in the middle of the runway, at 3000ft above the runway.

 

On the 777 here, there's an airline option to inhibit glideslope intercept in APP mode if you are not established on the Localizer. This means that when you hit the APP mode, the aircraft will need to be in LOC mode (Green, not Armed/White look at the PFD) before the Glideslope can capture. If you arrive "Above glideslope" then it will not 'descend to meet the glideslope'. This means the aircraft will not descend with the glideslope when it is not near the localizer. This is deliberate to protect the aircraft from descending with the glideslope when it isn't on course. an ILS has a surveyed protected area where by the glideslope is guarenteed to not hit hills and buildings etc. If you are 3 miles left of that, the glideslope might hit a hill, causing lots of dead 777 passengers. To avoid this, intercept the localizer on vertical profile if on an RNAV arrival, or as a general rule when using self-vectoring, more than 12 miles out and no more than 3000ft above the airport elevation.

 

In the PMDG 777, there's an option to turn this feature off, and so you can intercept and descend with the glideslope in APP mode even if you are well left or right of the localizer. This way the Autoland will still arm, and... assuming you don't crash into hills and structures on the way down, touch down on the glideslope somewhere near the runway, possibly even on it.

 

Here's some more things to consider when using an ILS. (To avoid confusion, this "False/Erroneous glideslope" problem won't happen in Flightsim FSX)


qfafin.jpg
Trent Hopkinson, 2013 Crewmember of www.mangrove.com.au WorldFlight sim

          Youtube channel www.youtube.com/user/musicalaviator


#8 wanabflyer

wanabflyer

    Member - 1,000+

  • Members
  • 1,909 posts
  • Joined 3 Years, 10 Months and 7 Days Ago.

Posted 08 September 2013 - 09:50 PM

LOC should always be selected first. After established on the LOC (LOC green on FD), if you require a full ILS/Autoland, then press APP. GS will display in white on the FD until glide slope capture, at which point GS will turn green.

Regards,

Rick Hobbs

Boeing777_Banner_Pilot.jpg

 


#9 hopskip

hopskip

    Member - 2,000+

  • Members
  • 2,066 posts
  • Joined 12 Years, 3 Months and 21 Days Ago.

Posted 08 September 2013 - 10:01 PM

LOC should always be selected first. After established on the LOC (LOC green on FD), if you require a full ILS/Autoland, then press APP. GS will display in white on the FD until glide slope capture, at which point GS will turn green.

Regards,

 

"Always" is a pretty strong term.

 

Try the LIZZI7A Arrival 16 at YMML, It's an RNAV with a 180kt max speed 90 degree left turn at 4000ft 13 DME from Melbourne.

 

The localizer and glideslope both intersect the RNAV section IN the turn at Bolinda BOL (ndb 362)

 

If you have APP mode selected as you start the turn, you will roll out wings level descending and with LOC & GS mode active.

 

If you don't... you'll probably be at 4000ft 2 dots above slope and increasing.

http://www.airservic...MMLSR05-135.pdf

 

Without rolling the MCP altitude window down and getting onto FLCH quick smart, then getting back on glideslope will be a bit of a battle. Intercepting the Glideslope from above out of FLCH is an option, but it's not the best option.


qfafin.jpg
Trent Hopkinson, 2013 Crewmember of www.mangrove.com.au WorldFlight sim

          Youtube channel www.youtube.com/user/musicalaviator


#10 wanabflyer

wanabflyer

    Member - 1,000+

  • Members
  • 1,909 posts
  • Joined 3 Years, 10 Months and 7 Days Ago.

Posted 08 September 2013 - 10:18 PM

"Always" is a pretty strong term.
 
Try the LIZZI7A Arrival 16 at YMML, It's an RNAV with a 180kt max speed 90 degree left turn at 4000ft 13 DME from Melbourne.
 
The localizer and glideslope both intersect the RNAV section IN the turn at Bolinda BOL (ndb 362)
 
If you have APP mode selected as you start the turn, you will roll out wings level descending and with LOC & GS mode active.
 
If you don't... you'll probably be at 4000ft 2 dots above slope and increasing.
http://www.airservic...MMLSR05-135.pdf
 
Without rolling the MCP altitude window down and getting onto FLCH quick smart, then getting back on glideslope will be a bit of a battle. Intercepting the Glideslope from above out of FLCH is an option, but it's not the best option.


I stand corrected. I should have said "almost without exception" however for the benefit of the OP, read the last paragraph on page 91 of Tutorial #1.

Regards,

Rick Hobbs

Boeing777_Banner_Pilot.jpg

 


#11 falcon999

falcon999

    Member - 2,000+

  • Members
  • 2,100 posts
  • Joined 12 Years, 4 Months and 15 Days Ago.

Posted 08 September 2013 - 10:27 PM

Another instance that will happen is that ATC will give a clearance to intercept the localizer but not clearance for the approach.
George Morris

Boeing777_Banner_BetaTeam.jpg

#12 wanabflyer

wanabflyer

    Member - 1,000+

  • Members
  • 1,909 posts
  • Joined 3 Years, 10 Months and 7 Days Ago.

Posted 08 September 2013 - 10:32 PM

Another instance that will happen is that ATC will give a clearance to intercept the localizer but not clearance for the approach.


Would this be if ATC was considering issuing a side step in the case of parallel runway?

Rick Hobbs

Boeing777_Banner_Pilot.jpg

 


#13 falcon999

falcon999

    Member - 2,000+

  • Members
  • 2,100 posts
  • Joined 12 Years, 4 Months and 15 Days Ago.

Posted 08 September 2013 - 10:37 PM

I guess it could be. I have gotten it for guidance to the airport and if there are multiple planes in line for the approach.
George Morris

Boeing777_Banner_BetaTeam.jpg

#14 hopskip

hopskip

    Member - 2,000+

  • Members
  • 2,066 posts
  • Joined 12 Years, 3 Months and 21 Days Ago.

Posted 08 September 2013 - 10:39 PM

Would this be if ATC was considering issuing a side step in the case of parallel runway?

 

On VATSIM it's usually when ATC is considering forgetting about you then wanting you to land from a position 2 miles short of the runway at 3000ft.

 

I once decended on my own with the slope and was told that I wasn't cleared for that, so I climbed back to 3000ft. When they issued the clearance for the approach I declared a missed approach due to being too high instead of reading the clearance for approach back. When they asked for clarification about the go around I told them that the reason that I was too high was due to him telling me to climb back above glideslope and maintain 3000ft. He somehow didn't realise that 11 miles from a runway at 3000ft is on the 3°.

 

He then cleared me to climb to the missed approach altitude.

So I descended to the missed approach altitude of 2500ft and read back "Descending to 2500ft missed".

 

yea, I get a bit snippy sometimes, but you can't climb to an altitude below you, and sometimes stuff needs to be said.

 

 

In my opinion, the main reason you don't hit APP mode straight away is the possibility of false glideslope capture. False glideslope is a feature of how glideslopes function (has to do with some physics of electromagnetic radio broadcasting) and if you arm APP early, it may capture a ~1° glidepath which is well below where you should be. Making sure you don't arm APP before the proper approach fix prevents this procedurally.


qfafin.jpg
Trent Hopkinson, 2013 Crewmember of www.mangrove.com.au WorldFlight sim

          Youtube channel www.youtube.com/user/musicalaviator


#15 FDX777

FDX777

    Member - 3,000+

  • Members
  • 3,272 posts
  • Joined 4 Years, 3 Months and 10 Days Ago.

Posted 08 September 2013 - 10:53 PM

You press LOC then APP


382725hvti09.jpg