A330 Smoke/Fumes/Avncs smoke checklist

[subria023]

Hi all,

I have just done my A330 type rating session regarding the in-flight smoke procedure and I am still trying to understand the reason for this particular action.

At the last part of the checklist when we are configured in ELEC EMER CONFIG,

- At 3 min or 2000 FT AAL before landing
-> ATT HDG SWTG.............F/O on 3
-> ALL GEN.......................ON

I can understand the ALL GEN to be back ON (in order to restore the necessary power sources for approach and landing). But what is the reason for the ATT HDG SWTG to be F/O on 3? I am trying to look up in both FCTM and FCOM but still no relevant answer.

Thank you,

Subria

[Steve the Pirate]

If you have selected EMER ELEC CONFIG during the checklist, IR3 remains powered whereas IR2 is only powered for 5 minutes and then becomes unpowered. When you later reselect the generators, IR2 is recovered but it won't provide valid data as it's not aligned. Also, when AC Bus 2 is re-powered, PFD2 and ND2 are recovered so the prior selection of FO on 3 ensures that the FO receives valid information from IR3.

I think that's it and I hope it helps.

STP

[subria023]

That makes a lot of sense now.

Steve the pirate - thank you very much !