<TDZE> what does it mean? landing surface
 

I'm a student pilot studying Jeppesen's Instrrument Comercial.






what does it mean?


1. TDZE : is the highest elevation in the first 3000feet of "landing surface".
Does "landing surface" mean just rwy served by app'?




2. LOM/IAF
SAVOY
356
The freq' underlined in this navaid facility box indicated that the navaid is without voice capabilities.


Does it mean only the marker beacon system gives "marker light" but not "aural"(continuous series of audio tone morse code) when passing the outer marker?

My understanding:

TDZE = touch down zone elevation (ICAO Doc 8400). The Jeppesen's reference to "landing surface" probably means "not necessarilly runway for all the times" i.e. heliport.


L/OM Savoy 356. Two things there, not to be confused. a) Outer Marker for the ILS facility: should produce lights and sounds in the cockpit through the reciever. Marker beacons have their own distinct (and same) frequiencies. b) The co-located Locator is in fact an NDB to be received with ADF. Whatever the "no voice" means I do not know, but assume it could be the lack of morse ident of the Locator(ndb). There is no reason why the OM should be affected at all, as these are two separate installations.

The point isyou cannot navigate towards an OM / MM / IM, you will only get the signal when passing over it. Hence the commonly used idea to put an (ndb) Locator into the same position.

TDZE - the highest runway centreline elevation in the touchdown zone. Touchdown zone is the portion of a runway, beyond the threshold, where it is intended landing aeroplanes first contact the runway.

Unless things have changed, the underlined NDB frequency means that the beacon transmits in modes A0 and A1 only, which means you have to use the BFO facility on your ADF receiver to hear the Morse ident.

thank you
 

you seem like b37 co-pilot. Thank you sir!. I will not confuse two things!

thank you
 

Thank you sir! I will search for BFO!

first off, BFO means: Beat Frequency Oscillator and is a circuit which turns a dry sort of dit and dah of a morse code into a more hearable blip and bleep.

AS FAR as NO VOICE. What that means is, they can't transmit on that frequency things. Believe it or not, ADF at one time was an important tool to send out wx info, or other communications.


VORs could be used to transmit in response to aircraft radio transmissions.

Like: Oakland radio, cherokee 2346D listening on Woodside VOR, request sequence report for MRY.

I feel old

To elaborate a bit.

A locator / outer marker has two different transmitters: An outer marker beacon, and a low powered NDB.

The marker signal is designed to have a very narrow width along the localiser course but fairly wide compared to the narrow orientation. This is to give a quite accurate position fix as the aircraft moves along the localiser, and still have the same effect if offset from the localiser a bit.

The nature of the beacon radiation pattern, and that of the localiser, means that it is not feasible to navigate to the localiser course to commence the approach from most azimuths, so...

...install an azimuth aid eg VOR, NDB that would allow the aircraft to be navigated to some point on the localiser that is suitable to commence the approach. The simplest - and cheapest - is to use an NDB. Low powered because it is intended for terminal navigation, not en-route - hence the term 'locator' (from 'compass locator' which was used to distinguish it from a 'radio compass', the old term for an ADF receiver)

There are different types of marker beacons: Outer, middle & inner. They serve to give position fixes along the localiser, something that is now usually done via DME or GPS. Marker beacons operate on a single, fixed frequency, and each type of marker beacon has a particular tone, ident & light colour associated with it. This lets you determine which marker you're crossing over.

Locators, being an NDB, albiet a relatively low power one, operate on various frequencies selected when installed so that each one doesn't interfere with others. This means that each locator, just like an NDB, needs a unique identification.

The identification used is an aural morse code. Trouble is, that aural signal has to be generated somehow to reflect some change in the base NDB signal that matches the desired morse code pattern.

One way to is have a plain, unvarying signal, and then use a some circuitry in the receiver to add an audio tone when it is receiving that signal. This is called a Beat Frequency Oscillator (BFO). If the locator (or NDB) signal is interrupted in such a way as to produce a Morse code pattern in it on-off-on-off pattern, then, in concert with the BFO you would hear a tone that matched the locators interrupted signal.

An alternative way is to have the locator's signal modulated just like an AM broadcast station, to allow an AM receiver to detect the amplitude difference and match that difference to an audible tone just like an AM broadcast. Not a voice audio though, just a beep when the amplitude is above a threshold, and silence below the threshold.

If the signal is further adjust in amplitude in away that is proportional to sound, then it would be like an AM broadcast radio station, and you could have additional information transmitted. Hence the with voice or without voice annotation.