A320 MCDU approach abbreviations

[Bagot_Community_Locator]

In an A320 (or any Airbus), how are the waypoints named after you insert an instrument approach.

For example, after I insert a VOR approach, the MCDU came up with waypoints :
CD34
FD34
MD34

I workout the 34 is for the runway, and F is FAF and M is MAPT, but what does the C and D stand for ?

C seemed to be the descent point, about 1nm before the FAF.

I couldn't work out what the D means.

Anyone know all the possible abbreviations you can get and what they mean ?

[westinghouse]

i think you'll have to ask airbus directly.....

from what i gather FD- Final descent
CD - Course descent
CI - Course intercept

pls correct me if im wrong.

[OPEN DES]

Can't find the related document unfortunately.

The first letter:
C is the centerline fix, usually coincides with a waypoint before the FAF/FAP

F is the the FAF/FAP

M is the MAPt


The second letter related to the type of approach:
D - vordme
V - VOR
Q - ndb
I - ILS
F - generic

I am sure there are a few more......

[airman13]

CD-Course to DME Arc
CF-Course to Fix
CI-Course to Intercept
DF-Direct to Fix
FC-Course from Fix
FD -Fix to DME Arc

Best rgds!

[laic]

It's in case of a (NPA) non-precision approach using RNAV. So in your case, it has to be RNAV VOR 34 approach to have this kind of coding. Right?
I mentioned that D could stand for Database, because for instance if you had FMGS failure(s), you would have to refer to your VOR 34 approach plate which could have for instance a higher MDA, using the good old VOR rose technique.
RNAV approach can be performed, provided:
The approach stored in the navigation Database has been validated, and is approved by the operator.
The final approach (FAF to runway or MAP) as extracted from the navigation Database and inserted in the F-Plan including altitude constraints, is not revised by the crew.
The approach trajectory is laterally intercepted before the FAF, or equivalent waypoint in the FM F-PLN, so that the aircraft is correctly established on the final course before starting the descent.
Mind you, D in this case could mean a DME related waypoint, but what I stated above is correct regarding the use of RNAV.
Maybe a LOC only approach would have a different coding. May be not if the waypoints are DME related.
I do not fly the airplane anymore so I cannot verify any of the above. Airbus issued an FCOM bulletin regarding this coding some time ago. I don't have it anymore unfortunately.
Let me know.

[Dani]

Airman13 is correct, and these abbreviations have nothing to do with Airbus, they are standard Arinc FMS database nomenclature.

[laic]

Dani,
You're right, it has nothing to do with them, but Airbus felt the need to issue a Bulletin to clarify this codiing.
One example used by Airman 13 is FD. He says it means Fix to DME Arc. It is actually the (D) Database (F) FAF we're talking about here. No ARC involved.
C obviously is for Course. The track from that point to the FAF should be the same then the track from the FAF to the runway. It is a requirement to do a RNAV NAP.
M as in Missed Approach is correct. The D, as above.
These 3 points are in line on your ND and the next thing after point MD, according to Bagot's example, should be runway 34.

[airman13]

Laic,

FD=Course from Fix to a DME distance. So I think 'D' comes from DME and not Database.As a matter of fact ,arcDME is a distance from that DME,isn't it?

[laic]

A330 FCOM BULLETIN, #10/2, dated july 01.
It's a 5 page document, approach plate size.
Subject: Use of FINAL APP and Nav Database Validation.
A few extracts:
.......the flight crew needs to have some basic knowledge of approach coding requirements.
CD= FACF= Final Approach Course Fix
FD= FAF= Final Approach Fix
MD= MAP= Missed Approach Point
In the approach profile used in the Bulletin, although the letter D is used to identify the Missed Approach Point, in both approach plate and FMS, it is not distance related, but height related. But I agree, DME is surely used to form most if not all of the approach waypoints.
Adressing it to your Training Department, they should be able to get the right answer for you.
Post back or PM, I would appreciate.

[Arrowhead]

Crikey - your FMGS sounds very modern. Our older ones have fixes such as D254M which means on the 254 radial distance 13DME (M=13th letter of alphabet).

Ho hum

[OPEN DES]

The letter D in 'MD' does not mean that the fix is DME-based!

The letter D signifies that the fix is part of an VOR/DME approach as I tried to mention earlier. It is an ARINC convention as noted by someone in this thread.

VORDME approach:

CD
FD
MD

VOR only approach:

CV
FV
MV

NDB only approach:

CQ
FQ
MQ

ILS approach:

CI
FI
MI

generic approach (where there is only 1 approach)

CF
FF
MF


There are a few more.
Also note that the database programmers do not always follow this convention.

[212man]

I tend to agree with Dani and A13: the D is DME and follows normal ARINC 424 logic. The only time D is not DME is when it is the prefix (e.g. DF) when it means Descent to (Fix). Clearly, by flying a VOR/DME approach, there will be DME fixes, whereas a VOR only approach will have none!