The "What does this mean?" thread

Jammyc

Just noticed that this board doesnt really have a jargon busting thread for the less educated enthusiasts (like myself).

Myself, I find that each time I listen to ATC I hear something different that I dont fully understand and I know that someone here must know the answer!

Mods apologies if this is inappropriate, I just thought it would be helpful!

So If I may, I'll get the ball rolling (if it'll roll).

When an aircraft is getting clearance for a departure, what do the various codes mean. For instance the other night I was listening to Dublin and aircraft were told that they were no longer departing from runway 10 and were instead to taxi to 16. This meant their departure changed from a Liffey 4 Alpha to a Liffey 4 Mike.

What does this mean exactly?:D Thankya!

andy_g

basically they change from rwny (runway) 10 to rwny 16 the liffey 4 alpha is the origanal departue plate that they were going to use instead were given a liffey 4 mike departure plate whay i mean by that is that the way the A/C (Aircraft) leaves the airport on a departure track

EchoIndia

andy_g wrote: »

basically they change from rwny (runway) 10 to rwny 16 the liffey 4 alpha is the origanal departue plate that they were going to use instead were given a liffey 4 mike departure plate whay i mean by that is that the way the A/C (Aircraft) leaves the airport on a departure track

You can find out lots more here:

http://www.iaa.ie/safe_reg/iaip/Frame1.htm

See section 2.24 at the bottom of the page.

Su Campu

Yes, a SID (Standard Instrument Departure) is a documented route they have to fly to get them to an airway (in this case, the the LIFFY waypoint on the L975 airway.

Here's the R16 SID chart for airliners. You can see that on a LIFFY4M they climb straight ahead towards Killiney, then after 3000ft turn left towards LIFFY. In reality though they don't fly these departures as ATC usually give them vectors after takeoff (eg. turn left direct LIFFY, climb FL230)

There are more charts for Dublin here

airvan

There ya go, the official IAA chart from the AIP. As you can see liffy 4 mike routes to Liffy, a notional point in the Irish sea after which you contact London.

http://www.iaa.ie/safe_reg/iaip/Published%20Files/AIP%20Files/AD/Chart%20Files/EIDW/EI_AD_2_EIDW_24-14_en.pdf

Here's a link to the AIP contents. At the bottom of the page are all the charts for Irish airports.

http://www.iaa.ie/safe_reg/iaip/aip_directory.htm

All the STARS and SIDS are there for you see. You'll find an explanation of those terms here http://www.iaa.ie/safe_reg/iaip/Published%20Files/AIP%20Files/GEN/EI_GEN_2_2_en.pdf Enjoy.

The AIP is a mine of info and is required reading for pilots.

Edit: great minds think alike!

ian_m

It means hes going to have to take the N1 instead of the N2... or the N4 instead of the N6...

ian_m

"Break-Break" is one I found the most interesting. Ending communication with one aircraft and beginning communication with another without pausing.

FlutterinBantam

Means there is an urgent instruction for the second aircraft, if that's what you are asking ,which necessitates breaking off conversation with the previous a/c.

Jammyc

Oh wow! Thank you all so much! Charts are dead interesting!

Ok so, heres probably a basic one but what exactly is QNH?

FlutterinBantam

Q= atmospheric pressure (at Nautical height) NH

therefore

QNH

http://en.wikipedia.org/wiki/QNH

ronnie3585

FlutterinBantam wrote: »

Means there is an urgent instruction for the second aircraft, if that's what you are asking ,which necessitates breaking off conversation with the previous a/c.

No. Break break does not relate to an urgent instruction. It relates purely to separation between messages when it's busy.

As per CAP413;

Indicates the separation between messages transmitted to different aircraft in a busy environment.

FlutterinBantam

:rolleyes:

Same difference.

Thanks anyway.

Killinator

Whats the altimeter(sp?) reference about, as in often at Shannon I hear over the ATC , Altimeter 2992(Two-Niner-Niner-Two), it only rarely differs from the 2992

Su Campu

I doubt you hear 2992 as that's not used in Europe, only America. Anyway, it means set your altimeter to sea level pressure of 29.92" of mercury (ie. 1013hPa)

donkey balls

Killinator wrote: »

Whats the altimeter(sp?) reference about, as in often at Shannon I hear over the ATC , Altimeter 2992(Two-Niner-Niner-Two), it only rarely differs from the 2992

its the presure at the airport/aerodrome so an inbound acft can set there altimeter to that setting which will give them the actual altitude at the airport.

the altimeter on a acft is only as good as the presure setting its actually asigned to so just say your flying from a to b and take off and climb to 4000ft by the time you get to b the presure could be different and even though the altimeter says 4000ft you could be at 3500ft

Mr Benevolent

FlutterinBantam wrote: »

:rolleyes:

Same difference.

Thanks anyway.

It doesn't indicate urgency though, which is what you mentioned.

yaeger

Never really heard QNH referred to as nautical height ! but thanks !

The Q codes arent really a shortened accroymn there are what they are ! A code system, Originated in war time and once referred to as Z codes, Now various people use them from Aviation to maritime and Met people.

You could call it nautical height but its not know as that, it could be called
Query Newlyn Height or Query Nil Height so that guestimation roles on, Best refer to them as CODES.

QNH is effectively the mean sea level pressure based on ISA to indicate altitude at that time.

Also QDM / QDR / QTE / QUJ / QSY / QGH / QFE / QNE / QFF


Break Break ! Same difference it isnt.

Killinator

Su Campu wrote: »

I doubt you hear 2992 as that's not used in Europe, only America. Anyway, it means set your altimeter to sea level pressure of 29.92" of mercury (ie. 1013hPa)

I'm probably mixing up what I hear in real life to the ATC in MS Flight Sim:D

Stovepipe

Hi there,
You will hear the "American" 29.92 at Shannon as it is commonly given to American air crews, along with the hectopascal number.American altimeters can have two Kollsmann windows, each indicating InHg or Hpa.
regards
Stovepipe

Pataman

donkey balls wrote: »

its the presure at the airport/aerodrome so an inbound acft can set there altimeter to that setting which will give them the actual altitude at the airport.

the altimeter on a acft is only as good as the presure setting its actually asigned to so just say your flying from a to b and take off and climb to 4000ft by the time you get to b the presure could be different and even though the altimeter says 4000ft you could be at 3500ft

I think you are mixing it up with QFE. QFE is the aerodrome pressure and shows the height above the aerodrome.
The 1013 setting is used above the transition level to make sure all flights are using the same setting and therefore maintain the correct seperation.
http://en.wikipedia.org/wiki/Transition_level#Transition_altitude