Maybe minor typo in docu
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Hi guys,
in BMS-Training.pdf it says in the middle of page 46:The second emitter is horizontal and guides the aircraft on the optimal glide path to the runway (3° in BMS).
It is called the glide path and is represented in the cockpit by a horizontal bar in the HUD and the ADI.
<<<I might be wrong, but I think the second sentence should start like:
It is called the glide slope …
<<<Just wanted to mention it and thanks for your docu
Sunnny -
Either term, Glide Path or Glide Slope, are used in aviation. I don’t think this is a typo at all.
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You are right, both terms “glide slope” and “glide path” are used in aviation.
But with all due respect I kindly ask you to reconsider, because I still see here a possible typo.
As far as I know and I might be wrong on this, the term “glide slope” usually refers to both the emitter and its corresponding radio beam, while the
term “glide path” refers to the descent of the aircraft ?If you look closely at both sentences above together in context and please correct me if I’m wrong, they basically say:
“The emitter guides the aircraft on the glide path. It is called the glide path.”Somehow this specific wording with the double use of “glide path” in this context here makes my brain stumble.
In my mind’s eye I see here the original intention of the author, to introduce the term “glide slope” by referring to the emitter in the same way as
he did before on the same page with the term “localizer”.I have to admit, that I do not have an IFR rating and I’m still learning about the fine nuances of English, which is a foreign language to me.
So please correct me, if I’m wrong.Just trying to help for improvement
Sunnny -
This post is deleted! -
I hesitate to differ from Red Dog (who I believe may be the author of that ILS Training section, and is meticulous in his research and his material) but I think there may be a couple of errors - depending on how you interpret the terminology used.
The section reads:
“The first emitter is vertical and called the localizer. It guides aircraft to the runway centreline. The localizer is represented in the cockpit by a vertical bar in the HUD, ADI and HSI.
The second emitter is horizontal and guides the aircraft on the optimal glide path to the runway (3° in BMS). It is called the glide path and is represented in the cockpit by a horizontal bar in the HUD and the ADI.”My understanding is that:
The Localiser is an emitter (VHF) in the horizontal plane (not as in airplane!) using a vertical bar on the ADI/HSI/HUD to show deviation from centre and yes, being horizontal plane guides the aircraft to within the centreline of the runway.
The Glide Slope is a vertical plane emitter (UHF) and so would guide the aircraft onto the correct glide path i.e. the ideal vertical path through the sky to reach the runway (not too steep, not too shallow) using a horizontal bar on ADI/HSI/HUD to show deviation from the centresee in Wikipedia https://en.wikipedia.org/wiki/Instrument_landing_system_glide_path
and here http://instrument.landingsystem.com/
I think the two paragraphs could maybe benefit from re-wording (Jetlag ducks as Red Dog swings!)
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I think you will understand it better, if you Google up ILS localizer (or glide slope), and look at the pictures. Let’s speak about localizer for instance, and forget glide slope for a minute, as it wouldn’t exist at all. Your LOC instrument senses two vertical beams, one means “too much left, go right”, the other one the opposite. The two beams each have to be oriented vertically, otherwise (if they would be oriented horizontally), your LOC instrument wouldn’t see them if you would be anywhere “above”, or “below” the localizer beam. So if you are off to the right (regardless of your altitude !), your antenna gets the right side beam’s (vertical shape) signal stronger, which moves your LOC bar to the left. Now if you go left, you start drifting back into the left side beam (which is also vertically oriented, so that your instrument can pick it up in any altitude), that tells you “you are left, go right”. Flying in the middle, the two beams are like two equally strong springs, that are each trying to pull the needle to themselves, so in the middle the two beams have equal effect on the needle, so it stays in the middle. But the “left” and “right” beams themselves, each has to project it’s own signal vertically. Hope this helps, sorry, if a bit confusing.
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My understanding always been:
Glide path : trajectory
Glide slope : instrument (horizontal needle)… well apples and apples.
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To “loop the loop” as we would say in Spanish, FAA AIM definitons
GLIDEPATH− (See GLIDESLOPE.) GLIDEPATH [ICAO]− A descent profile determined for vertical guidance during a final approach. GLIDESLOPE− Provides vertical guidance for aircraft during approach and landing. The glideslope/glidepath is based on the following: a. Electronic components emitting signals which provide vertical guidance by reference to airborne instruments during instrument approaches such as ILS/MLS, or b. Visual ground aids, such as VASI, which provide vertical guidance for a VFR approach or for the visual portion of an instrument approach and landing. c. PAR. Used by ATC to inform an aircraft making a PAR approach of its vertical position (elevation) relative to the descent profile. (See ICAO term GLIDEPATH.)
So… nowadays used interchangeably apparently… but traditionally I agree with Dee-Jay’s point of view… G/S = ILS/MLS vertical guidance beam, G/P = approach descent trajectory in general.
Also, despite the above definitions, never heard the word “glideslope” in the context of a PAR approach (“approaching glidepath”, “slightly below glidepath”, etc… instead), and I would also feel quite “uneasy” if somebody mentioned the “VASI/PAPI glideslope” to me -
G/S = ILS/MLS vertical guidance beam, G/P = approach descent trajectory in general.
Nailed it.
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Therefore, to address Sunnny’s original question, and according to Dee Jay and Ahmed’s comment, should the manual read as:
It is called the glide slope and is represented in the cockpit by a horizontal bar in the HUD and the ADI
as that sentence refers to the instrument and not the trajectory?