PPRuNe Forums - ADR 1+2+3 FAULT - LDG DIST PROC

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- - ADR 1+2+3 FAULT - LDG DIST PROC - no delta VRef? (https://www.pprune.org/tech-log/628285-adr-1-2-3-fault-ldg-dist-proc-no-delta-vref.html)

Superpilot

25th Dec 2019 18:27

ADR 1+2+3 FAULT - LDG DIST PROC - no delta VRef?

Happy Christmas!

According my QRH for a very new A320 NEO, under PER-J, there is no delta VRef to apply in the case of an ADR1+2+3 fault, but there is for a dual ADR fault. What am I missing? My guess is Airbus logic is that a triple is also a dual and you must apply the corrections for that first?

safelife

25th Dec 2019 21:04

Without any ADR you're lacking the speed info to apply delta Vref to... you’re on BUSS then.

giggitygiggity

26th Dec 2019 19:13

Quote:

Originally Posted by safelife (Post 10647374)

Without any ADR you're lacking the speed info to apply delta Vref to... you’re on BUSS then.

If you have a BUSS!

Although, with an ADR 1+2+3 fault (assuming it’s a computer problem rather than a probe issue) the ISIS should still work so calculating an appropriate VAPP could be used to cross check the ISIS with the BUSS green triangle. I’d expect VAPP to be VREF+15 as it’s direct law.

Skydreamerii

12th Jan 2020 19:53

On "old" a320 we have it. Vref +10 with config 3.

FlightDetent

13th Jan 2020 13:26

checked some -214 / -232 / -271N, they show "All ADR OFF" : CF = 3; SPD = n/a

might be the planes are all BUSS equipped.

vilas

13th Jan 2020 15:10

From FCOM: "ADR3 and STBY speeds use the data of the same probe. Therefore standby instrument must be used with care".
EFB gives landing distance separately for ADR 1+2 and ADR1+2+3 which is 800mtr more than ADR1+2. Vapp shown in both cases works out to Vref+10. Without BUSS.you will fly attitude and thrust and not speed.

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