How do you get G-load out of the MCDU?
Anybody knows a way to get the G-load at touchdown out of the MCDU?
|
Must have been a good one eh? :}
|
Anybody knows a way to get the G-load at touchdown out of the MCDU? |
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. |
|
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.
|
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
|
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: |
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 |
Without checking the AMM
Longtitudinal Acceleration, Lateral Acceleration, Pitch Rate, Roll Rate, Radio Altitude Rate. Work later, will correct if wrong |
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. |
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. |
All times are GMT. The time now is 19:53. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.