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Rick1407
24th May 2018, 22:56
The A320 SOP has a note saying that: "To avoid damage on the RTLU (Rudder Travel Limit Unit) mechanical stop, the SLATS/FLAPS should be retracted before all ADIRS are set to OFF simultaneously."
Is That means that it is not allowed to perform a fast or full alignment with Flaps 1 out ?
i saw in a TFU that the problem is only when you perform a Complete Alignment, it don't say nothing about the fast Alignment...
Does any one have a more detailed information about this ?

FlightDetent
24th May 2018, 23:58
That's thorough thinking. No idea, AMM would help. Not so much the FCOM.

BTW have you noticed, that the "recent" requirement to do full/fast alignment on transit stop has been fortunately removed?

Rick1407
25th May 2018, 00:15
That's thorough thinking. No idea, AMM would help. Not so much the FCOM.

BTW have you noticed, that the "recent" requirement to do full/fast alignment on transit stop has been fortunately removed?

Yes, as far as i can remember, now we perform a Fast Alignment when a complete is not required... in other words, every leg... it moved from supplementary to the SOP.

pineteam
25th May 2018, 05:05
Not required anymore to do a fast alignment on every leg. The procedure has changed again. Yeah!:}
If you want to do an alignment with conf 1 and prevent damage to the RTLU mechanical stop, just keep one ADIRS in normal position and align 2 of them. Then when alignment is completed, do the last one. A bit of an hassle tho. Unless you operate in the middle east, I would not leave the flaps out after landing. Not worth the risk of having a refueling truck striking the flaps/slats. Just my opinion. Some guys will keep conf 1 after landing, then retract them just before entering the gate.

If you want more information on why the RTLU mechanical stop get damage, Level600 explains it nicely here: https://www.pprune.org/tech-log/561955-a320-rtlu-damage.html

MD83FO
10th Jun 2018, 12:32
What if you switch them off and on one at a time?

FlightDetent
10th Jun 2018, 14:14
What if you switch them off and on one at a time?
FCOM: To avoid damage on the RTLU (Rudder Travel Limit Unit) mechanical stop, the SLATS/FLAPS
should be retracted before all ADIRS are set to OFF simultaneously.

Tango23
10th Jun 2018, 14:19
What if you switch them off and on one at a time?

great point, yeah what if they are not done simultaneously?

pineteam
10th Jun 2018, 14:59
Have a look to my post above. Yes you can do that. As long as not all of them are switched off simultaneously, it’s fine.

Edit: I beleive at least one must be on AND aligned to avoid the damage to the RTLU.

MD83FO
12th Jun 2018, 03:39
the question that arrises now is, what constitutes a proper alignment, when i did the type rating in 2004, the FCOM 4 stated that all 3 IRSs should be turned on simultaneously for an ideal alignment and the from/to inserted as soon as the IRS's were switched on to minimize drift

vilas
12th Jun 2018, 06:49
MD83
What you say is correct. For quick alignment all three need to be switched off and then on. Possibly because if you kept one on the data from that may degrade the quality of alignment. Although in the age of GPS primary may not be critical. The answer to flap1 and RTLU issue appears to be to retract it with yellow electric.

Rick1407
14th Jun 2018, 17:47
the question that arrises now is, what constitutes a proper alignment, when i did the type rating in 2004, the FCOM 4 stated that all 3 IRSs should be turned on simultaneously for an ideal alignment and the from/to inserted as soon as the IRS's were switched on to minimize drift
You are correct, if you reset one ADIR at a time you will damage the RTLU because even if you reset one at a time you still ganna have the FAC 1+2 fault on the ecam, and thats the problem. FAC supply the RTLU in therms of air speed, and once they have lack of information, the Emergency Return to low speed mode will activate. But as far as i could find, this problems only will happen if you perform a Full Alignment, when a Fast Alignment is performed, a Battery Clock ensures that the FAC will not be without speed data during those 5 seconds.

Escape Path
15th Jun 2018, 03:27
We had the "fast alignment on every transit" too, but fortunately it was removed some months ago. We now have a company circular on how to align with flaps at 1 (operating in the Caribbean you will get OAT <30C at MSL airports). We are suggested to retract flaps with yellow pressure, realign, then back to 1.