I have followed this thread with considerable interest and sympathize with anyone attempting 20/25 Minute Turnarounds on Medium Haul Aircraft as standard practise.
Somewhile ago, when I had access to the tools I did some analysis and the reults are:
The critical path analysis of the 'generic' Turnaround which includes Cleaning and Cabin Grooming would not show Flight Deck Checks as a problem.
In very general terms would give a turnaround as being 30 to 40 minutes, with the Cabin Cleaning and Grooming Standard required being the main variable.
However once you feed in a time for turnaround of 20 Minutes, then Midjet is right that Flight Deck procedures are now a critical element and it is a 'close run thing' and if the checks result in 'a tech query' then a delay is inevitable.
If you take out cabin Cleaning/Grooming then 25 Minutes is achievable as a standard, but it allows no real margin for any section involved (difficult cargo offload/onload, special needs passenger group etc), but this works on the 'generic airport', i.e. No account of any special circumstances at that station (including Security Requirement bottlenecks etc).
If you now move to the Transit Case where you are just dealing with Pax and Baggage On/Off (no Cargo, No Crew Change and slightly less required in the way of checks, No Scheduled Fuel Uplift, Catering change, Cleaning etc) Then at the 'generic airport' 20 Minutes is feasible. But this makes 'huge assumptions'.
The first being the Passengers are called to the Gate prior to Aircraft Arrival and the Security and Pax Services Team have effectively processed the bulk of them prior to the Aircraft Arriving on stand. The bulk of the outbound baggage is pre-positioned a the stand holding area.
Of course when planning 'real' Turnarounds, the actual Airport circumstances must be factored in and that should not just include the basic Facilities set, but probable Stand/Gate allocation, coaching, steps only, etc, and at busy airports time of day.
But this case still (normally) assumes no real limitation on Airport Staff Resources.
There have always been exceptions, one from what most of you would consider ancient history was at the height of the 'The Troubles' the planned Turnaround at BFS was 14 Minutes Chock to Chock with Full Load of Pax and Mixed Belly load Cargo. But everyone was fully resourced and geared up to do it (including the Passengers :-)
Now to close this bit of the post out, when planning at Main base/Hub add 10 minutes to your to full turnaround analysis, mainly to give Engineers time to deal with the accumlated minor 'snags' but also to give a 'punctuality' margin!
But the real world isn't like this, well not anymore:
The Handling Negotiations are purely Cost based and the Turnaround Time is planned on the Transit Time which as near as damn it defines the minimum possible ground time and this is applied globally to the Route Network. So all the above analysis (even if the airline bothered to do it) goes out of the window.
The Airline will be asking for the world for 50p and the Handling Agent (aware of the competition) will agree to it.
As this thread proves:
Regardless of how professional the Handling Agency staff are, the end results are Delays which accumulate as there is little, or no recovery planned into the programme. Good people deciding it's time to leave aviation, Passenger and Crew frustration and finally but most importantly Concerns that the 'holy grail of safety' is being undermined.
As this trend has been going on for a number of years, I have come to the sad conclusion that unless the CAA do become involved and regulation is enacted, nothing will change, except that working on the ground in Passenger Services, Load Control/Dispatch etc will become something only the financially desperate, or otherwise unemployable will want to do!
As for Delays and allocating Delay Codes:
I once worked for an airline (as a dispatcher) that at various times worked to +5, +3 and Zero tolerance delay standards. The Zero Tolerance period was I later found out (when I put on a suit), to prove a serious point. However as being part of the Airline rather than an Agent we were in a position to allocate the delays as we saw them and not have to fudge to preserve anyones feelings/jobs/contract. I am NOT saying that on (too many) occasions we didn't operate rubber watches.
The most contentious delays were those down to Flight Deck, which were fought tooth and nail by Flt Ops every morning at the Delay Committee. Sometimes (as I later discovered) even when proof was available the rest of the committee gave in (life too short)!
But when I was working as a relatively junior member with a group tasked with reducing Handling delays (we ignored the Delay Commitee findings as being 'over processed'), we found that because in general terms the dispatcher reports were accurate (if in many cases cynical), that once the statistics guy had put them through various tools, the patterns that emerged enabled root cause problems to be isolated and in time many were resolved.
From memory a lot of them were not resourcing problems, but getting resources where required, when required. The result was a significant reduction in delays with a positive financial benefit.
A similiar analysis on route Airports was less successful, but did change the schedules for the Scottish and French departures at certain times of day.
Inaccurate delay reporting, in the long term doesn't benefit the Handling Agency (although proving this is the case to their Management is almost impossible) and it doesn't benefit the Airline nor the travelling public.
But from this thread it appears that currently the Airlines don't care, the Handling Agencies daren't care (if they are to stay in business), the Staff who do care are being worn down and Joe Public is resigned to it.
Hmm for some reason reminds me of the last years of British Rail!
Sorry for 'rambling on for so long'
DIH