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Coffee Black None
17th May 2007, 06:50
Anybody knows a way to get the G-load at touchdown out of the MCDU?

Dream Land
17th May 2007, 08:02
Must have been a good one eh? :}

FS-chick
17th May 2007, 08:35
Anybody knows a way to get the G-load at touchdown out of the MCDU?
If the display is broken you have pulled more than 5 g's in the flare. :ouch:

Gary Lager
17th May 2007, 08:55
MCDU Menu
CFDS
Man Request reports
Load Report (I think)
The figure you want is on the printout as VRTA

Have I missed anything?

From memory, not FCOM, so please amend as req.

Disclaimer: your company may have restrictions about non-maintenance personnel accessing the maintenance functions of the FMGS. Mine does. So don't be naughty.

FCS Explorer
17th May 2007, 09:10
http://www.pprune.org/forums/showthread.php?t=269925&highlight=vgtd

primreamer
17th May 2007, 09:42
I'm open to correction here because its been a while, but as I remember for Airbus, after normal flight and landing, if you access the load report through the CFDS with the aircraft at rest all that will show under VRTA is the vertical load at that moment, i.e. zero. VRTA is monitored at touchdown and if you want to find out what it was then you need to download and interpret the DFDR data for the last flight. Having said that, if VRTA limits are exceeded at touchdown then a Load Report #15 should be generated, stored and printed automatically by the CFDS. As I said the grey matter is a bit cloudy so feel free to shoot me down.

Gary Lager
18th May 2007, 22:51
You could be right, think you need to get a printout which gives the landing info. I forgot to check on Weds. Must try harder

idg
19th May 2007, 06:48
Load 15 can be set to print automatically but I think the default is for it not to print like this. Operators have to set the ACMS to do it.

As has been said the data is not a direct readout of vertical accel on touchdown because of the sampling rate. If you were lucky to hit the recording just right (pardon the pun!) it would still not read the true rate for reasons already explained by others. Some fairly complex calcs are required to work out if it was 'heavy' and sometimes Airbus have to be involved as well.:ok:

TO MEMO
19th May 2007, 14:43
Quite interesting. I tryed it and for FMGS with MCDU menu I found it on:

MCDU menu
AIDS
Load Report

Requested a print and all values during landing event were printed.
Actually all values from 1 sec before landing to 2 sec after are printed. If you bounce, those values will be retained.

Some values are easy to understand what they are, as Pitch att, roll, etc., but there are some I have no idea. Those are:

LONA, LATA, PTCR, ROLR, RALR values

Can anyone decode those?

Cheers

Wodrick
19th May 2007, 16:06
Without checking the AMM
Longtitudinal Acceleration, Lateral Acceleration, Pitch Rate, Roll Rate, Radio Altitude Rate.
Work later, will correct if wrong

ChristiaanJ
19th May 2007, 16:33
Re sampling rate, does anybody have figures?
As said before, vert accel makes little sense as a datum for a hard landing. It's a transient, sampled at a few points.
I would have thought vert speed (the last few points before it abruptly becomes zero - or even positive....) would be a far better indicator, but again, that's true only if the sampling rate is not too low.

TO MEMO
20th May 2007, 10:54
Yesterdays landings:

VRTA = 1,25g
VRTA = 1,17g

Was told by the airline accident prevention advisor, that QAR registers as hard landing any value above 1,8g if I`m not mistaken. I`ll check that value with him again and will correct if wrong.