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- There's not a lot of subjectivity
when it comes to airfield planning.
- [Narrator] This is Rob Hoxie,
a veteran airport planner.
He's helped on airfield projects across the globe
from Portland, Oregon to Abu Dhabi.
Now he's here in Chicago,
leading the Aviation Department's development projects.
- And if we look here at the layout of O'Hare.
- [Narrator] O'Hare, which Airports Council International
ranked as the second busiest airport in the world
by aircraft takeoffs and landings
has just completed a more
than 15-year-long modernization project
that's transformed its airfield
and its 14 and a half miles of runway.
- One airfield on the north, one airfield on the south,
and the passenger terminal complex in between.
- [Narrator] Hoxie's here to explain
how airfields are mapped out,
what factors planners must consider in their design
and how all of this impacts your on-time arrival.
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- So the three primary things that we look at
in starting to plan an airfield
would be runway orientation, runway length
and overall runway configuration.
That is how runways are configured approximate
to one another.
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Runway orientation pertains to how the runways
are situated relative to compass heading.
- [Narrator] Whether north-south, east-west,
northeast-southwest, northwest-southeast,
the direction of the runway
is determined by the wind.
- In Chicago, our predominant direction of wind
is either westerly or easterly.
So having runways on an east-west orientation
makes a lot of sense here.
If you look at a place like Dallas, Forth Worth,
you end up with wind conditions
that are predominantly out of the north or the south.
And therefore, the runways wanna be oriented
in a north-south direction.
- [Narrator] The reason? Headwind.
Planes function best when departing
and arriving into a headwind
as it helps give departing planes lift
and slow down arriving planes.
Tailwinds and crosswinds, though manageable,
can impact aircraft performance,
making takeoffs and landings tough.
To determine prevailing wind direction,
airport planners consult historical data.
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- We look at on a per-hour basis
over at least a 10-year period
what direction winds were blowing from,
at what speeds and velocities,
both kind of steady state, as well as gusts.
- [Narrator] The target, according to an FAA recommendation,
is for the primary runway to provide
at least 95% wind coverage.
In a windy city like Chicago,
that's not possible.
The airport has to be prepared for shifts in wind direction.
- O'Hare has enough periods of the year
where winds either blow strongly out of the south
or out of the north
that it also needs coverage with runways on a diagonal.
We have two runways that we term the crosswind runways.
That is they are used when the crosswind component,
either out of the north or the south is too great
to be able to operate effectively
on the east-west oriented runways.
- [Narrator] Before O'Hare's modernization began,
it had a triangle shape,
including north-west to southeast runways
but with more data,
the team was able to make changes.
- The four new runways that we've opened,
all are on an east-west orientation.
10 center, 10 right, nine center and nine left
were all opened as part of the O'Hare modernization program.
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The next thing that leads into airfield planning
is establishing how long runways needs to be.
- [Narrator] Runway length is not uniform across airports.
The type of aircraft an airport needs to accommodate
and the local weather conditions
factors heavily into how much pavement is needed.
And it's not even the same for arriving
versus departing flights.
- Arriving flights generally land
with low amounts of fuel.
Then the weight of the aircraft and the weight
of the people onboard.
At O'Hare, we accommodate a range
of different aircraft types from regional jets
to the biggest of aircraft
with more than 400 passengers onboard
and a lot of fuel.
- [Narrator] That aircraft's overall weight
and the airspeed at which it's traveling
into its touchdown are put into a formula
that also takes into account local weather conditions.
- When one goes through mathematical calculations
of all of those different parameters,
we arrived at 7,500 feet
as the ideal length for an arrival runway.
- [Narrator] O'Hare now has three 7,500-foot runways,
and another around 8,000 feet,
which are all used primarily for arrivals.
Departing runways, remember, are different.
- Your long intercontinental flights
that really drive your departure length requirement
on an airfield.
Fuel is the major variable,
and the weight of the fuel means
that the plane is heavier
and so with a heavier plane,
it requires a greater length
to achieve the airspeed
that ultimately allows it to take flight.
- [Narrator] The result?
Longer runways for departures.
At O'Hare, that meant building one runway 13,000 long.
That's more than two miles in a straight line.
That wouldn't cut it at Denver International, however.
That airport has five 12,000-foot runways
and one stretching 16,000 feet,
making it the longest commercial runway
in North America.
- Any time you have a hot and high climate
like we have in Colorado,
runway length is generally longer
than it is for an airport at sea level,
and where temperatures overall are more moderate.
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- [Narrator] Finally, planners need to place the runways
and where the pavement goes is crucial for traffic flow.
- We first look at what is an hourly requirement
for arriving traffic?
What is an hourly requirement for departing traffic?
And if you merge those two at the same time,
what's our total two-way requirement
at any given point in time?
- [Narrator] At O'Hare, arrivals alone
can reach 114 flights per hour,
which meant placing those runways further away
from the terminal and the primary departure runways closer.
And importantly, it meant creating more parallel runways.
- If we look at O'Hare's old configuration,
the intersecting runway configuration essentially degrades
how many flights per hour could be accommodated
on a single runway.
- [Narrator] That's because landing on one runway
becomes dependent on another runway being clear
of aircraft to avoid any chance of planes colliding.
- The results of this reconfiguration plan
have largely untangled the runways from one another
and given us a much better balancing
of a good weather arrival rate
and a bad weather arrival rate.
And ultimately, that leads to the stability
for our airline partners who operate here.
They no longer have to cut 20 flights from their schedule
per hour as soon as the clouds show up in O'Hare.
- [Narrator] O'Hare's airfield is now able
to accept four airfield landing at the same time.
The first commercial airport in the country
to allow for this.
The point of all of this work,
whether it's O'Hare modernization
or the construction of a new airfield
is to move more travelers through the airport
in the safest, most efficient way possible.
- Prior to the modernization plan,
in good weather, O'Hare would land this runway,
this runway, and this diagonal runway
as one of its configurations.
With that, the airport could achieve an hourly arrival rate
in the low '90s.
If we were to add a fourth parallel approach,
that would increase the arrival rate
into the upper 130s to the low 140s.
- [Narrator] But as many travelers know,
this kind of efficiency isn't always achieved.
Delays happen.
- [Rob] That's something that has plagued O'Hare
and other congested airports around the country
for the better part of several decades now.
- [Narrator] Since O'Hare opened its first new runway,
it has cut the more controllable system delays
by more than 60% compared with the five years prior.
Still, Department of Transportation data shows the airport
is trialing the average on-time arrival rate
for all major US airports so far this year.
- We can't control all forms of delay with infrastructure.
You still may be missing crew,
you still maybe have a maintenance issue
affecting a flight, and there are other factors as well.
But for the addressable delay,
that is what we can build our way out of.
We've made significant strides
to improve the traveling experience.
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