A319/20/21

[AIRBUS58]

FROM YOUR EXPERIENCE OF AIRBUS FAMILY ,. .WHEN THE APU IS SUPPLING AIR THROUGH THE PACKS ,DO THE PACK VALVES OPEN STRAIGHT AWAY OR IS THERE A NOTICABLY DELAY BEFORE THE VALVES OPEN.

[graham.oliver]

on a good morning (first flight of the day ) it can take about 20 mins to get a dodgy valve on line, once on line it works fine though , the only solution change it or live with it

[LBMF]

They will be slow to open if you switch both packs at once. Select one pack & when open select the other. Not the most reliable of things the A320 FCVs. Often a valve stick in low flow, many people pen this off ( usually LGW) but the valve should be replaced ASAP in case the other valve fails.

[moleslayer]

As long as the packs are left selected 'on'when the final shutdown checks are done,then the next apu air 'on' selection will start the packs in a 1 then 2 delayed sequence(10secs).. .My outfit used to select the packs 'off' at the end of the day,the early morning start up was a tedious on & off rigmarole,until the temps equalised.. .Airbus'told us that with the "new" software the packs should be always left 'on',this has cured it for us in most cases.

[Ali Crom]

Have been involved with similar problems regarding Pack problems especially on first flight of the day on the 319. There is a simple mod which has been designed to improve the reliability of the air conditioning system and is being incorporated on the BA fleet. It involves the removal of a sense line & fitment of a blanking plug at the FCV. Once this has been accomplished, the existing valves can then later be interchanged with an improved, later spec assy.

[SnapOff]

Yep, also had experience of this. I seem to remember that there is a TFU from Airbus about it and I believe the valves are being mod'ed. As far as I can remember the valves worked a lot better after the mod. If you are replacing the valves watch out, everyone I changed had damaged threads on one of the sense line connections so had to change that as well !

[WenWe]

Sure you're not confusing sticky acm's with reluctant pack valves? Does the valve indicate 'open' but the pack is silent? The acm's can be a bitch to get started up first flight of the day - often a bit of apu boost on the eiu (or pulling the zone cntrlr cb's) to get a bit more chuff from the apu & some juggling of pack valve switches will get them going tho'.. .If the pack overheats with the pack valves 'on' its a stuck acm.. .As an aside, if you've got pfcv position indication probs - try a new sdac first. Might save a lot of grief.