Just answered an interline question, which reminds me of what an alliance is for.

Just wondering, how on earth do they *NOT* work? I've had it happened to me when flying on CX (on either end of the interline). Both times, amazingly, was on premium cabin, tho.

1) Apr2011. I flew award F HKG-xLHR-FCO with an overnight connection as part of a longer award ticket. CX F Checkin agent at the airport F counters said they cant overnight check bags at LHR for FCO (I queried and agent insisted no). fast forward 36 hours, the checkin agent at LHR was surprised i didnt thru tag my bags and confirmed (along with FT) that overnight checking is possible in LHR.

2) Nov2013. J LHR-KUL-TPE-HKG. I gave MH agent at T4 LHR my ticket for TPE-HKG (CX) but he called MH and said thru check is not allowed. Anyways, the transit desk at TPE sorted it out, as able as they always are.

but... WHY? is my question

It depends in the length of the layover, I think. I suspect overnight is permitted, but not for more than 24 hours. I fell foul of this doing CX HKG-BOM then BA BOM-LHR. My "connection" was 24 hours and a few minutes and I checked bags through - but on landing in BOM was told I had to retrieve bags and re-check them after all...

what a pain

Part of the problem from the pax perspective is that the airlines create unreasonable expectations about what an alliance can deliver. In practice, they're still separate companies with their own rules, procedures, etc. And you can't realistically expect every member of frontline staff at every alliance carrier to understand all of the rules that might impact any interline itinerary even with the best training, which the carriers often don't seem to provide anyway. It's a recipe for frustration.

Have the same problem when I'm flying SEA-SFO-HKG. Get into SFO in the morning and out on CX873 (night time flight). Layover is less than 24 hours, but AS won't interline anything over 12 hours.

my TPE connection is 2 hours. and i'm talking a reasonably large port (2*A380/day from MH); or ex-HKG from CX. I don't think i'm being unreasonable here.

what a pain: yes - when you have a 20kg bag that you dont need overnight AND fly F.

is this even an unreasonable expectation when there *is* interline agreement?

I can answer both as I've had personal experience with similar scenarios but not only with CX...

1. LHR - If all connections are on the same ticket , then YES, you are allowed to thru check via LHR on an overnight, ie next day - but it must be first flight out to your final destination. It cannot be the 'usual' 23 hour rule. But if you're on seperate tickets, even with connecting at LHR with first flight out, it is then not permitted. I had a CX flight from HKG-x/LHR-AMS and CX will not thru check since it was an overnight on a seperate ticket. The agent explained to me the reasons why and it was on her computer specifying the fact. When I flew SQ SIN-x/LHR-CPH, the agent could thru check me and the connection was the first flight eg 6am flight out. The agent explained that these rules are specifically for London Heathrow.

2. T4. I suspect that DL is the ground agent for MH and they cannot thru check on seperate tickets. Generally MH is ok to thru check on difference alliances even, so connecting to CX would have been fine. There are interline arrangements on - but if the ground agent isn't well versed in issues like this - maybe the DL agent forgot that MH has joined OW !

US / Canadian airports will also not allow connecting bags to stay overnight. eg security issues.

I was chatting with an agent at PEK the other day and she told me that when there's a connection for more than 6 hours, the chances of your luggage being lost would increase significantly

Mine was on CX253 to an early morning FCO flight... unless it wasnt the first one out in the morning (which i dont think so) - and on one big fat award ticket.... oh well...

Which BA flight?

Then the error could have been read by the check in agent... unless CX have their own policies regarding overnight kept luggage at LHR. Nothing you can do about it - Perhaps you can check with airport check in staff (supervisor) for clarification?

SQ allows it - see my explanation above.. so maybe you can ask CX why they don't and SQ allows it? Then maybe ask other airlines too.. eg EK.

My recent experience on interline from CX to MH, overnight in Seoul.

Routing:
HKG-ICN(CX)
overnight in Seoul
ICN-KUL(MH)

I asked and confirmed with a check-in agent at CX counters HKIA a few days before my flight, whether it is possible to do such interline. The agent confirmed it is possible as MH and CX are interline partners, and as long as the connecting time is under 24hrs.

Fast forward to the day of my flight, the CX agent said it is not doable because it involves an overnight layover at the airport. I insisted and she asked her supervisor, the supervisor came and and asked if I am staying at the airport, and I said no, she then said becasue of security issues, the bag needs to be with the passenger. I then insisted saying another checkin agent has said it is possible as long as it is under 24 hours. She then double checked, and reluctantly said it is possible, but I shall bear the risk of the baggage getting lost or things getting stolen or something. The checkin took so long, at least 10 minutes. Next day at ICN at MH checkin desk, just showed the MH agent my baggage tags to confirm if the bags have been loaded to the flight, it was. Easy and simple.

Long story short, I think some agents are reluctant to interline/check through bag involving an overnight layover. For airports like HKG, SIN, ICN, I believe there is space to place overnight baggage, so I don't think there are any issues. Plus, many people connects through these hubs everyday anyway.

if they hadnt changed the schedule big time, the 7.30 one. (or the only one that leaves before 8am unless they have removed early morning schedule to FCO)

yes thats the first flight.

Must be the CSO at CX misunderstood the rule. But anyway Interline is not a right so they can choose to stop it anytime they want (which sucks!) Try this on BA and the results will be worst. (even if it is BA/BA)

It's not like you're going to retrive your luggage at ICN, what "security" difference does it make if pax is sleeping on a bench in the airport...vs out in the city overnight