Welcome, Guest. Please login or register.
Did you miss your activation email?
November 26, 2014, 01:32:05 AM
Home Help Login Register      
News: LiveATC.net Flyers Released!  Please click here to download & print a copy and be sure to post at an airport near you!


+  LiveATC Discussion Forums
|-+  Air Traffic Monitoring
| |-+  Listener Forum (Moderators: dave, RonR)
| | |-+  Very newbie question
« previous next »
Pages: [1] 2 Go Down Print
Author Topic: Very newbie question  (Read 5785 times)
u00bgw1
Newbie
*
Offline Offline

Posts: 4


« on: February 16, 2009, 10:31:17 PM »

I just started listening to this site and by no means am I a pilot but wondered about these terms.

What is a localiser and a marker? During the tragic ATC comms for flight 3407 they kept saying they had passed the marker. Thanks in advance for the answers....

Ohh...and what is an altimeter (sp)?
Logged
ATCWanAaB
Newbie
*
Offline Offline

Posts: 48


« Reply #1 on: February 16, 2009, 10:47:55 PM »

The Localizer is a radio beam emitted from the airport to help the pilot line up along the center line of the runway. It is one component of an Instrument Landing System (ILS) along with the Glideslope which provides a decent path to the runway.

Along the localizer, there are "markers" which are established x distance from the runway.

An altimeter is a device that measures the outside air pressure relative to a datum (set by the pilot) to determine an aircrafts altitude. So if a controller says:

"Delta 233, altimeter 29.98" he is simply giving the pilot the reference datum.

If you have more questions, or want more detail, feel free to ask!
Logged
u00bgw1
Newbie
*
Offline Offline

Posts: 4


« Reply #2 on: February 16, 2009, 11:23:46 PM »

Thank you sir!
Logged
mkop
Newbie
*
Offline Offline

Posts: 29


« Reply #3 on: February 17, 2009, 11:41:54 AM »

Along the localizer, there are "markers" which are established x distance from the runway.

Getting a bit more technical, how is the OM (outer marker) specified? Is it based on DME of the localizer signal, or what?
Logged
KSYR-pjr
Hero Member
*****
Offline Offline

Posts: 1722



« Reply #4 on: February 17, 2009, 12:18:20 PM »

Getting a bit more technical, how is the OM (outer marker) specified? Is it based on DME of the localizer signal, or what?

In many cases, the outer marker used to be a radio antenna located anywhere from 3 to 7 nautical miles (depending on practicality and topography along the approach path) that would vertically broadcast a modulating tone on a specific frequency.  On-board, a radio pre-tuned to this frequency would receive this signal when the aircraft crossed over the antenna and the pilot would see the OM light illuminate while a modulating tone would be heard over the audio (assuming the pilots activated the audio for this).

In some cases, a non-directional beacon would be co-located with this antenna, providing the pilot additional situational awareness along the approach. See this WIKI description for some animation and better description.

However, here in the States outer markers are being decommissioned on almost a daily basis as the FAA looks to reduce the cost to maintain the national airspace system (NAS).   GPS waypoints of the point along the approach that once represented the outer marker are taking their place. 
Logged

Regards, Peter
ATC Feed:  Syracuse (KSYR), NY
RV1
Full Member
***
Offline Offline

Posts: 104


« Reply #5 on: February 17, 2009, 09:01:20 PM »

"Getting a bit more technical, how is the OM (outer marker) specified? Is it based on DME of the localizer signal, or what?"


On our RADAR scopes, it is indicated by a dash. If the dash is missing, we use a grease pencil to put a dash where we think it should be... evil
Logged

Kick butt, take no names, they dont matter anyways
joeyb747
Hero Member
*****
Offline Offline

Posts: 1583


Nothing Like A 747!


« Reply #6 on: February 19, 2009, 06:33:03 PM »

There is actually three markers on approach to the runway. Outer, Middle, and Inner. On the panel in the cockpit, three lights, blue for outer, yellow for middle, and white for inner, light up as the aircraft crosses over each one. I have linked to a pic of an L-1011 First Officer Panel. The lights are located just to the right of the altimeter.

http://www.airliners.net/photo/UK---Air/Lockheed-L-1011-385-3-TriStar/1482266/L/&tbl=COCKPIT&photo_nr=27&sok=&sort=_order_by_photo_id_DESC_&prev_id=1482477&next_id=1482238

Logged

Aircraft Mechanic
djmodifyd
Guest
« Reply #7 on: February 19, 2009, 07:06:49 PM »

There is actually three markers on approach to the runway. Outer, Middle, and Inner. On the panel in the cockpit, three lights, blue for outer, yellow for middle, and white for inner, light up as the aircraft crosses over each one. I have linked to a pic of an L-1011 First Officer Panel. The lights are located just to the right of the altimeter.

http://www.airliners.net/photo/UK---Air/Lockheed-L-1011-385-3-TriStar/1482266/L/&tbl=COCKPIT&photo_nr=27&sok=&sort=_order_by_photo_id_DESC_&prev_id=1482477&next_id=1482238



if im correct....only cat II/III approaches have IM's....otherise there is only an outer and middle marker
Logged
joeyb747
Hero Member
*****
Offline Offline

Posts: 1583


Nothing Like A 747!


« Reply #8 on: February 19, 2009, 08:19:27 PM »

I think you correct about that djmodifyd. Im not 100% on that. That technology is going by the wayside. New aircraft navigate more with GPS now days then traditional radio based nav aids. Anyone remember LORAN??  grin
Logged

Aircraft Mechanic
KSYR-pjr
Hero Member
*****
Offline Offline

Posts: 1722



« Reply #9 on: February 19, 2009, 09:02:46 PM »

On the panel in the cockpit, three lights, blue for outer, yellow for middle, and white for inner, light up as the aircraft crosses over each one.

As the FAA continues to decommission markers on approach, you are going to find that these panel lights will become as obsolete as the ADF is here in the States.
Logged

Regards, Peter
ATC Feed:  Syracuse (KSYR), NY
cessna157
Hero Member
*****
Offline Offline

Posts: 708



WWW
« Reply #10 on: February 19, 2009, 10:56:37 PM »

will become as obsolete as the ADF is here in the States.

AD----What?  What's that?

I actually can't believe that in the CRJ900s I flew, which were equipped with 2 FMSs, 2 Com radios, 2 Nav radios, 2 transponders, and 2 GPSs, that they'd still bother to equip them with 2 ADFs.  Not once did I actually use it in anger.  Sometimes I'd dial one in and turn the pointer on just to see what would happen.  Half the time it'd be pointing 20 degrees away from where the FMS/GPS said it was.
Logged

CRJ7/CRJ9 F/O, Travel Agent
pilot221
Guest
« Reply #11 on: February 19, 2009, 11:08:56 PM »

will become as obsolete as the ADF is here in the States.

AD----What?  What's that?

I actually can't believe that in the CRJ900s I flew, which were equipped with 2 FMSs, 2 Com radios, 2 Nav radios, 2 transponders, and 2 GPSs, that they'd still bother to equip them with 2 ADFs.  Not once did I actually use it in anger.  Sometimes I'd dial one in and turn the pointer on just to see what would happen.  Half the time it'd be pointing 20 degrees away from where the FMS/GPS said it was.

They are good for one thing, listening to sports games.
Logged
carthis
Newbie
*
Offline Offline

Posts: 3


« Reply #12 on: February 20, 2009, 12:22:59 AM »

Yep, listening to AM radio is the only thing I use the ADF for... Smiley
Logged
atcman23
Sr. Member
****
Offline Offline

Posts: 367



« Reply #13 on: February 20, 2009, 07:34:53 AM »

As the FAA continues to decommission markers on approach, you are going to find that these panel lights will become as obsolete as the ADF is here in the States.

Only after the new "NextGen" system is in place and everything is satellite-based.  As of right now, the markers will have to stay as they make up part of the ILS approach and all three markers are key in Cat II/III approaches.  Eventually, yes, they will be phased out and cockpits will likely be updated to include new equipment that will be required and they'll likely take out old equipment that is obsolete to make room for the new stuff.

So, maybe by the time I'm 60 or so, we'll see this happen...  tongue
Logged

Mark Spencer
KSYR-pjr
Hero Member
*****
Offline Offline

Posts: 1722



« Reply #14 on: February 20, 2009, 08:41:43 AM »

Only after the new "NextGen" system is in place and everything is satellite-based.  As of right now, the markers will have to stay as they make up part of the ILS approach and all three markers are key in Cat II/III approaches. 

Hmmm... perhaps the middle and inner markers are still being retained due to their requirement on Cat II/III approaches - not being Cat II/III certified I haven't paid attention to their plight.   

However, as far as the OM is concerned, it definitely is no longer required.   Here at SYR, which has a Cat II ILS approach, the outer marker on that particular ILS approach was decommissioned sometime over the last couple of years and our little blue OM blinkey is definitely not there anymore.  Take a look at the Cat II approach plate taken from MyAirplane.com's most current set of NACO charts:




Also, in looking at some of the Cat II/III approaches into JFK I see also that OMs are not indicated on their charts, implying that they also have been decommissioned.
Logged

Regards, Peter
ATC Feed:  Syracuse (KSYR), NY
Pages: [1] 2 Go Up Print 
« previous next »
Jump to:  


Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2011, Simple Machines Valid XHTML 1.0! Valid CSS!