Bagageafhandeling op luchthavens
Report 2001.TT.5491, Transport Engineering and Logistics.
This report gives a broad view of baggage handling on airports. Although
the time required to sort and transport luggage often prevents flights being
thighter scheduled, baggage handling is often underestimated considering
design and extension of airports. The continuing growth of airtraffic has to
be handled by a small number of airports that is forced to expand. The
expansion causes an ever growing amount of luggage to be transported over
increasing distances. This greatly affects the process of baggage handling.
Many baggage handling systems transport 'raw' baggage. The conveyability
of raw baggage is extremely bad due to the different attributes of luggage.
This causes the big airports to transport baggage in tubs (or: totes / trays).
The so called 'tubbing'. Baggage that can not be dealt with automatically
even in tubs, is called: oversized, oddsize or 'out-of-gauge' (OOG). This
baggage forms a separate flow that in itself is not efficent but does not
effect the capacity of the automated system. Efforts to further increase
the amount of baggage that can be dealt with automatically, are not worth
the price. The most critical baggage flow consists of transferbaggage;
very often this baggage determines the 'minimun connecting time'.
The baggage is labeled at check-in so it can be identified automatically
in the sortation system. The IATA label is the nowaday standard. The error
percentage while reading this label automatically lies between 3 and 50 percent.
Radio Frequency IDentification (RFID) is supposed to be the next standard. Its
only disadvantage being the high costs, but RFID chips are getting cheaper. More
and more the passanger has the possibility to check-in his baggage early.
This spreads the flow of orginatingbags better but requires an
'early-baggage-storage'(EBS). Due to strict safety measures it must be
possible to approach luggage in the EBS quick and even individually. If the
tubs are strong enough, conventional storage systems can be used. 100% Hold
baggage screening (HBS) is compulsory by the end of 2002. New scan
techniques and better image processing makes online scanning possible
without any effects on the capacity of the baggage handling system.
The concept of the airport terminal buildings greatly affects the design
of the baggage handling system. American airports mostly consist of a
number of highly independent terminals with their own ( decentralised) baggage
handling facilities. These facilities are often simple and a great deal of
manual sortation is done. Passengers often have to transport their luggage
themselves from the one terminal to the other. More and more passengers do not
accept this and airports are trying to link their terminals. These links often
do not cover the whole airport and transportation distances are long. The
European airports are strongly centralised and the baggage handling
systems are highly automated. When an airport has to expand beyond the
radius of the central terminal building, the so called 'satellites' arise.
Transport distances and the necessary transport velocities increase
greatly in case of satellite terminals. Simulations have proven the
transport distances to be the smallest in case of linear midfield terminal
The baggage handling process can be divided in 'inbound' and 'outbound'.
It looks if inbound, the handling of arriving baggage, is optimised:
the tranfermix is manually sorted while loading the majority on the
reclaim caroussel and the passengers sort the destination bags themselves.
The originationg bags have to be sorted after destination, class, transfer
or not, etcetera. It depends on the size of the airport if sortation can
be done manually or has to be done automatically.
The sortation process consists of: order selection; premerge accumulation;
merge; induction; takeaway.
Merge and accumulation are not possible when handling raw baggage due to the
possibilty of jams. Raw baggage has to be sorted as passive as possible on
a closed conveyor surface. Suitable for transportation are also only
beltconveyors. Suitable low to medium rate sortation equipment is in fact
only the specially developped vertisorter. Because of the lower costs and
smaller dimensions the less suitable pusher sorter is most widely used. The
only suitable high rate sorters are the tilt-tray sorter and Destination Coded
There are no restrictions in suitability of low to medium rate sortation
equipment if baggage is conveyed in sufficient strong tubs. Although in that
case there are no restrictions in high rate equipment too, again only the
tilt-tray and DCV are really suitable. Most high rate baggage sortation systems
consist of a tilt-tray sorter with beltconveyors for short distances and
baggage tugs and carts for long distances. DCV systems are gaining, however,
due to their much higher transport velocity. This higher velocity is of
growing importance with the expansion of the airports. Furthermore, as already
mentioned: more and more main airports are considering 100% tubbing to improve
conveyability, create efficient EBS and improve tracing: every piece of baggage
should be approachable individually as long as possible. It seems also logical
to send luggage in its own tub on a route dependable of its destination through
the system: Destination Coded also. Frankfurt is the best example of such a
system. This system has a number of disadvantages, however, like high
energy consumption and wearing, that a Destination Coded Vehicles system
does not have.
The transportation velocity of a DCV systems is higher than of a tilt-tray
sorter system. Furthermore the availability ofa DCV systems is higher:
The whole tilt-tray sorter has to be running to sort only one bag, while
only one DCV has to ride to deliver one bag; energy consumption is also
lower with a DCV system. This in combination with the higher availability
makes the running costs lower with a DCV systems than with a tilt-tray
sorter system. Knowing this makes the major disadvantage of DCV systems: the
very high investment costs less impressive.
- A DCV system is less vulnerable while the probability of a system breakdown
is the same as the probability of one DCV breaking down: the probability of
a system breakdown is the product of the breakdown probabilities of each
part alone in case of a tilt-tray sorter system;
- Maintenance and repair can be done elsewhere with the system still
functioning in case of a DCV system. When one tilt-tray sorter segment or
one belt conveyor in a line has to be repaired, the whole sorter or line
has to be halted.
Nevertheless: a DCV systems will only be interesting facing very long
transportation distances, in case of major airtraffic hubs, also. A limit
of 40 million passengers pro year has been found in literature: above this
limit a DCV system should be preferable above a conventional tilt-tray
sorter system. It lies beyond the scope of this report to prove this this
limit; the comparision has been made qualitatively only.
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