This is news to me... i work for an airline with lots of Airbus Airplanes.
QRH page 123, amended 01, Oct. 16states:
All ADR Off: "BUSS equipped aircraft when require by the ECAM NAV ADR 1+2+3 FAULT procedure."
1. SPD......................................................... .....................FLY THE GREEN
2. MODE SEL......................................................... ..........MAN
3. MAN V/S CTL......................................................... ......AS REQRD
for aprroach
4. SPD......................................................... ......................FLY THE GREEN
5. FOR LNG......................................................... ..............USE FLAPS 3
6. GPWS LDG FLAP 3.........................................................ON
7. landing distance procedures apply
8. APPR SPD......................................................... .............FLY THE BUG
it don't say nuthin about descending to FL 250???