View Full Version : Alternate law Airbus 320
Alhamar86
7th Jul 2022, 15:28
Is it possible to perform auto land in alternate law , when you have all three SEC’s inop. In order to avoid disconnection of autopilot and reverting to direct law ?
Is it possible to perform auto land in alternate law , when you have all three SEC’s inop. In order to avoid disconnection of autopilot and reverting to direct law ?
Do a belly landing.
sonicbum
7th Jul 2022, 20:16
Is it possible to perform auto land in alternate law , when you have all three SEC’s inop. In order to avoid disconnection of autopilot and reverting to direct law ?
Note:If SEC 1+2+3 fail, the LGCIU information can no longer be sent to the ELAC. For the activation of DIRECT law, the ELAC uses the condition “slats and flaps in CONF 2” instead of “landing gear down”.
Rocket3837
8th Jul 2022, 08:25
Is it possible to perform auto land in alternate law , when you have all three SEC’s inop. In order to avoid disconnection of autopilot and reverting to direct law ?
If I recall, yes you can auto land the A320 with all SECs inop...
handsome goafer
8th Jul 2022, 14:43
From the MEL ENTRIES a paragraph at the end of each SEC failure (i.e. Sec 1, 2,or 3) basically says if the other two fail Autoland is not permitted.
Maximum landing capability is CAT1
ref MEL 27-94-01A, 02A and 03A
Rocket3837
8th Jul 2022, 16:41
The A320 is definitely capable of auto landing with all SECs inop. Here I am talking systemwise. However, regulation wise it is not permitted...
regarding the "CAT 1 only" indication on FMA, this doesn't always mean that the plane is unable for auto land....it means that AFS is no longer fail passive/operative...
Thanks
Rocket3837
8th Jul 2022, 16:47
Note:If SEC 1+2+3 fail, the LGCIU information can no longer be sent to the ELAC. For the activation of DIRECT law, the ELAC uses the condition “slats and flaps in CONF 2” instead of “landing gear down”.
I don't think this true....
With all SECs failure, the LGCIUs can still supply ELACs with gear info...
The scenario you are talking about occurs when both LGCIUs fail. In this case the AFS uses SFCCs to switch to Direct Law ..
tubby linton
8th Jul 2022, 17:18
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/2000x472/671e837d_eb32_472f_a18e_4b602240a4b1_730d73fd9474e429917d957 0e3aaaa3cefff189b.jpeg
The fcom I looked at for this failure shows Cat 3 dual inop on the status page which means that Cat 3 single would still be available.
I don't think this true....
With all SECs failure, the LGCIUs can still supply ELACs with gear info...
The scenario you are talking about occurs when both LGCIUs fail. In this case the AFS uses SFCCs to switch to Direct Law ..
No! LGCIUsv don't supply the ELACs in this case. It's flap2 that signals direct law. It's clearly given in FCOM ABN procedures.
lurkio
8th Jul 2022, 18:53
Handsome Goafer :ok:
Right at the bottom of the Operational Procedure for each SEC is the magical line Cat 1 only. Hidden where most normal humans don't go in flight (unless they are REALLY bored).
Strange it's not listed in the required equipment in the Ops section of the QRH given it is a definite requirement and the prohibition is really buried.