I left the Directorate of Air Operational Research in 1988 and moved
to Canadian Forces Base Trenton where I worked at the Air Transport Group
Headquarters of the Canadian Air Force.
My first project there was to improve on the Operational Research team’s
strategic airlift simulation. I wrote a
discrete event simulation using the Fortran version of Averill Law’s Simlib system from his book Simulation Modeling and Analysis 
. This simulation calculated the time to
complete an airlift for various departure intervals. The departure interval is the time between
departures of each transport aircraft.
It is important to space the departures reasonably far apart to allow the
ground crews to load the aircraft at the origin and off-load the cargo at the
destination. I was asked to use this
simulation model to estimate the time to complete the airlift of fighter
aircraft support materials during the first Gulf War when the CF-18 was
deployed to Qatar. I presented this simulation at the 1990
Canadian Operational Research Society Conference in Vancouver.
My main finding using this simulation was that the time to complete the
airlift was constrained by two bottlenecks when the departure interval is
changed. When the departure interval is too large, there are many aircraft waiting to fly which creates a longer duration. When the departure interval is too small, there is a limit to how many aircraft are available to fly. This means the duration of the airlift will be no shorter with a smaller departure interval. There is a "sweet spot" when the departure interval is just right. Then aircraft are both available and not waiting. When these bottlenecks come into effect the results of the simulation
can be approximated by straight lines and the "sweet spot" is where these two lines intersect.
This was a very interesting result that I found occurred many times in
my future studies. Namely, that system
performance is dominated by bottlenecks and we wish to find an optimal place on the performance dimension where the bottlenecks are applied equally.
. This simulation calculated the time to
complete an airlift for various departure intervals. The departure interval is the time between
departures of each transport aircraft.
It is important to space the departures reasonably far apart to allow the
ground crews to load the aircraft at the origin and off-load the cargo at the
destination. I was asked to use this
simulation model to estimate the time to complete the airlift of fighter
aircraft support materials during the first Gulf War when the CF-18 was
deployed to Qatar. I presented this simulation at the 1990
Canadian Operational Research Society Conference in Vancouver.
My main finding using this simulation was that the time to complete the
airlift was constrained by two bottlenecks when the departure interval is
changed. When the departure interval is too large, there are many aircraft waiting to fly which creates a longer duration. When the departure interval is too small, there is a limit to how many aircraft are available to fly. This means the duration of the airlift will be no shorter with a smaller departure interval. There is a "sweet spot" when the departure interval is just right. Then aircraft are both available and not waiting. When these bottlenecks come into effect the results of the simulation
can be approximated by straight lines and the "sweet spot" is where these two lines intersect.
This was a very interesting result that I found occurred many times in
my future studies. Namely, that system
performance is dominated by bottlenecks and we wish to find an optimal place on the performance dimension where the bottlenecks are applied equally.
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