I'm curious how bags are transported from the terminal sortation system to the aircraft. I'm mostly trying to understand the "average tarmac distance" a bag will travel. If anyone has direct insight into that metric that might be even more helpful than understanding the process.

I grabbed a screenshot of the United Terminal at DIA to try to map out how this could be implemented. Can anyone help with insight into which process implementation is generally used in the industry?

Sort Points at Each Gate

  1. Each gate has a "sort point" and bags are transported a short distance from that gate sort point to the plane parked at the gate.

One Sort Point

  1. One sort point serves "N" number of gates. One baggage handling Cart serves only one plane. (How big is "N" if this method is used?)

enter image description here

  1. One sort point serves "N" number of gates. One baggage handling Cart may serve several planes, detaching a section of the the train at each craft.

Are any of these methods used? Or perhaps could several sort points feed one aircraft? Does this vary airport-to-airport or airline-to-airline? Who is generally responsible for the design of the process - the airport or the airline? Do ULDs have a different process than each-loaded bags? What about smaller regional jets loaded at the far ends of the terminals - are their sort points further away? How does the process look for offloading bags from the aircraft?

  • 1
    $\begingroup$ I don't think there is a universal answer to this question, each airport may have different baggage handling systems/procedures. $\endgroup$
    – Ron Beyer
    Apr 20 '21 at 13:37
  • 2
    $\begingroup$ I agree with Ron. Procedures will vary widely and depend on airport layout, as well as equipment and personnel available throughout the day. For example, a modern busy airport with underground conveyors and automated sorting would benefit from the apparent efficiency shown in the first photo, while a small regional airport with one licensed tug driver would necessarily need to follow the example in the third photo. This might be a useful and interesting topic if you could distill the question into one more answerable or help us understand a specific problem you are trying to solve. $\endgroup$ Apr 20 '21 at 14:19
  • $\begingroup$ And what is a ULD? $\endgroup$ Apr 20 '21 at 14:20
  • $\begingroup$ @MichaelHall ULD = Unit Load Device. i.e. container into which freight is loaded, then the ULD is loaded on the plane. $\endgroup$
    – FreeMan
    Apr 20 '21 at 15:00
  • $\begingroup$ Just my 2c, while yes not every airport is the same, there are many shared elements and the question does ask for the general implementation. A specific airport will be much harder to answer. $\endgroup$
    – ymb1
    Apr 21 '21 at 16:44

From your photo this answer assumes a hub airport.

Some background first: after check-in, the belt conveyor system moves each bag onto its own tray – that's the modern individual carrier system (ICS) which mitigates jams, misreads, and lost baggage. Depending on how early the check-in took place, the tray will either go to a holding area, or directly to the baggage makeup area/space (BMA) where the bags are unloaded onto another belt conveyor system for cart/ULD loading.

BMA is the place you referred to as sort area. There is typically one BMA per airline per pier, and since big airlines usually have their own piers, it's one BMA per pier. Example for San Francisco Intl (see tan colored areas):

enter image description here

Two hours or so before the flight's STD (scheduled time of departure), comes the cart/ULD staging. The cart train length varies; IATA recommends 3 carts per narrow-body and 5–6 per wide-body. Airlines however implement this as best fits them. Easyjet for example stages one cart per narrow-body at Liverpool (internationalairportreview.com).

Regarding how many gates are served per BMA, one of the methods used to estimate the floor area required for a BMA when designing an airport is the EQA, or Equivalent Aircraft factor (see FAA AC No: 150/5360-13 for more).

In short, it's option 2.


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