I've had these lights go off from time to time with loud beeping, but I don't know what they mean (I'm guessing engine over heat, stall warning etc) but I'm not sure and cannot find any reference to it in the learning center. Can someone please give me a definition of these letters/lights and what the mean when they go off?O=M=I=thanks alot in adavance for your help

http://www.navfltsm.addr.com/ils.htm

Outer, Middle and Inner marker beacons for an Instrument Landing System. Each has its own tone:The outer (blue) light comes with a long "booop booop booop" tone and is usually the approach fix for intercepting the ILS.The middle marker (orange) is a lot closer to the runway and has a "beep beep beep" mid-range tone.The inner marker (white) hs a high pitched, fast, "bipbipbip" tone and means you are very close to the end of the runway.Unfortunately, despite officially being qualified to fly ILS in the real world (although I never have since training), I can't remember the exact distances from the threshold. Hopefully someone else can trot those off the top of their heads shortly! :-)Hope that helps - try looking under the instrument navigation and/or ILS sections of the FS guide.Ian P.

The OM is generally 5-6 miles from the landing runway threshold. It's usually placed near the point where the glideslope is intercepted, though it can vary some. The MM is generally around the DH point, or about 200 feet agl if you're on the glideslope. The IM is around the landing threshold, and I believe is only encountered on a Cat II or III runway.Also, marker beacons are gradually being phased out. New ILS installations do not use them.

>Outer, Middle and Inner marker beacons for an Instrument>Landing System. Each has its own tone:>>The outer (blue) light comes with a long "booop booop booop">tone and is usually the approach fix for intercepting the>ILS.>>The middle marker (orange) is a lot closer to the runway and>has a "beep beep beep" mid-range tone.>>The inner marker (white) hs a high pitched, fast, "bipbipbip">tone and means you are very close to the end of the runway.>>>Hope that helps - try looking under the instrument navigation>and/or ILS sections of the FS guide.>>Ian P.Thanks Ian and everyone else that took the time to enlighten me, this helps alot!

No-no-no-no-no-no these replies give information that is all entirely incorrect. O M I is a special radio device that indicates impending doom. This is what the signals mean:O = "Oh"M = "My God"I = "I'm going to crash"Citation: FAR 91.21375 para A(A word to the wise - you just can't believe everything you read on the internet, as evidenced by the seemingly 'authoritative' replies to your question in this thread. Caveat emptor: be careful and make sure that these whoosits with their "blue light - outer marker" stuff really know what they are talking about. "Outer Marker" -- hmmph! -- what is that, a crayon?)

Ok Guys, Well, for once, this kindly old man is going to be a wise a$$. OMI That is a foreign language for READ THE MANUAL, IT EXPLAINS EVERYTHING!Sorry, couldn't resist this time.Clay

>No-no-no-no-no-no these replies give information that is all>entirely incorrect. O M I is a special radio device that>indicates impending doom. This is what the signals mean:>>O = "Oh">>M = "My God">>I = "I'm going to crash">>Citation: FAR 91.21375 para AROFL best one yet hehe.. But seruisly the firs time i flightsimed back in the good ole days i hear this deep beepeing noise as I passed over a beacon it scared the bejesus out fo me :)And It gets me all the time as well i just cant get used to it...

#### head!! Too many stubbies!

Boy a severe case of RTFM!!!!

>The middle marker (orange) is a lot closer to the runway and>has a "beep beep beep" mid-range tone.It's actually the same tones as the Inner and Outer Markers. So you'd hear da-da-da-da over the Outer, dit-da-dit-da on the Middle, and dit-dit-dit-dit over the Inner.----------------------------------------------------------------John MorganReal World: KGEG, UND Aerospace Spokane Satillite, Private ASEL 141.2 hrs, 314 landings, 46 inst. apprs.Virtual: MSFS 2004"There is a feeling about an airport that no other piece of ground can have. No matter what the name of the country on whose land it lies, an airport is a place you can see and touch that leads to a reality that can only be thought and felt." - The Bridge Across Forever: A Love Story by Richard Bach

I bet nobody imagined this would turn out to be such an amusing thread!What amuses me is that you've had these things going off "from time to time"No that suggests your are like me, plenty of approaches, not to many landings, never managed to keep on the glideslope long enough to realise they go off one-by-one as you approach the runway....So instead of going O->M->I you are following my preferred routes:1) The place you spot the runway lights from, oh it's over there, I can get this 767 around there->Middle Marker->Medium Stay Car Park2) Outer Marker->I'm a bit low actually better pull the nose up->VSTOL landing 60ft short of Middle Markerand on good days3) Outer Marker 27L->Middle Marker 27R->Oh well that one will do

>Boy a severe case of RTFM!!!!Well since this was written over a year ago...amazes me that you guys took the time to go and dig it up...but since then I have found the info that I was looking for last YEAR!! and if you do not have anything constructive to add to the request FROM LAST YEAR...go read your own manual. I was reading the manual when I asked...had not found it yet at that time. Check the date on the thread before replying next timeAmazing simply amazing the stupidity of human beings at times

>....>>So instead of going O->M->I you are following my preferred>routes:>>1) The place you spot the runway lights from, oh it's over>there, I can get this 767 around there->Middle Marker->Medium>Stay Car Park>>2) Outer Marker->I'm a bit low actually better pull the nose>up->VSTOL landing 60ft short of Middle Marker>>and on good days>>3) Outer Marker 27L->Middle Marker 27R->Oh well that one will>doYou sound like you've been looking over my shoulder, 'cept I fly proppies instead of those long toothpaste tubes. When yer in a bitty little plane ya kin even horse one aroun' ta thet marker ya missed on the first go.:D

I was recently watching a video tape of Croydon Airport 1919 to 1939. On the video they had a "beacon" that was on the apron or somewhere near. Anyone know if that was the prdecessor of the OMI beacons. This one was a large thing brightly lit as a visual homing beacon which I know they also have today but just wondered. Anyone with a brain out there? ;-)Andrew Brownhttp://www.gordiusfs.pwp.blueyonder.co.uk/