Crazy airport runways: Landing on half a runway—why it’s business as usual in Alaska

March 20, 2019 Johnathan Limb

Remote, single-runway airports require unique design considerations—and often operate under half-width conditions during construction

 

More than 80% of Alaska’s communities are connected to the outside world not by a road but by an airport. And when it’s time to repair the runways at many of those airports, we end up slicing the runway in half during construction. That leaves pilots about half the width of the typical runway for takeoffs and landings—maybe as little as 30 feet for the smallest airports—and it's not crazy, it's business as usual.

As engineers in the far north, we often find ourselves having to come up with creative solutions that allow completion of repair and expansion work while still allowing the airport to serve the community.

 

The runway at the Ralph Wien Memorial Airport in Kotzebue, Alaska, is just 6,300 feet long and is essentially surrounded by water. During runway reconstruction, airplanes—including Alaska Airlines jets—had to operate on just half the 150-foot-wide runway.

 

So how do we do it?

First, within special rules from the Federal Aviation Administration (FAA). Secondly, by creative engineering and important project phasing, with a focus on safety. We split the runway longitudinally down the middle, close one half for construction while the other half remains open for airport operations. When personnel and equipment are working on the closed half, the entire runway is closed to aircraft operations—often requiring construction work to occur at night outside of scheduled flights—in the name of safety.

Yep, we do things differently in Alaska!

 

Working within a unique set of FAA rules for runways

Per the FAA’s 150/5370-2G Operational Safety on Airports During Construction advisory circular (AC), if runway rehabilitation is required, the runway must be closed until construction is complete or the runway is returned to a state where aircraft can safely operate—which could be an entire summer or, depending on project size, multiple years.

_q_tweetable:In Alaska, our remote communities typically rely on an airport with a single runway and apron, with a taxiway that connects the two—and not much more._q_In Alaska, our remote communities typically rely on an airport with a single runway and apron, with a taxiway that connects the two—and not much more.

Generally, operations are so low at these airports that parallel taxiways are not the norm nor are they economically justifiable. If the FAA required Alaska airports to follow the typical rules enforced elsewhere in the US and to close the runway for construction, it would completely shut down the airport and isolate the community—no mail, groceries, medevacs, or travel, all of which occurs through aviation. Remember, these communities are not connected to the road system. There is no road system!

The airport—and its runway—is a lifeline.

At larger airports, where we have the luxury of a parallel taxiway, it’s typical to repurpose that taxiway as a temporary runway and close the runway until the project is complete, which is a common practice in most parts of the US.

 

The 100-foot-wide runway at Gambell Airport was sliced in half for reconstruction during 2018. Gambell, home to about 680 people, roughly 60 miles from Siberia Russia. Markings clearly define the active and the closed portion of the runway.

 

Asking and answering the important runway questions

It starts with cooperation. We work with the airport sponsor, the users, and the FAA to develop a safe plan to split the runway. Understanding when flights need to use the airport, the size of the customary aircraft, and how to maintain service for medevacs is important to ensure we keep the airport open during critical times of the day. In 2012, the FAA’s Office of Airport Safety and Standards (AAS-300) released their Runway Half Width Operation Construction Guidance memo to the Alaska Airports Regions Division Office (AAL) listing the requirements to allow half-width operations. The first step is determining if the runway can be closed. From the memo, the following questions must be answered:

  • Does the airport have a second runway of sufficient capability?
  • Does the airport have a taxiway of sufficient length and configuration to be used as temporary runway?
  • Are there any viable transportation modes available, such as year-round roads or frequent ferries?

If the answer to any of those questions is “yes,” FAA requires the runway to be closed during construction. For example, in 2015, we worked with the City & Borough of Juneau to resurface the Juneau International Airport’s sole runway. Because the airport has a full-length taxiway, we used that taxiway as a temporary runway during the 3½ months of construction. Per the FAA’s memo, half-width construction wasn’t an option in Juneau.

In other communities, however, additional considerations need to be made for the following questions:

  • Does closing the runway have unacceptable impacts on the community?
  • Can emergency medevac flights be accommodated?
  • Are there published terminal procedures or required navigation performance (RNP) procedures that would be impacted?

FAA will review all factors and make a final determination if half-width operations are warranted. Since airport construction is very disruptive to communities, any planned runway closures or modifications to airport operations need to be coordinated with local community leaders and all stakeholders to ensure that all airport operations and safety considerations have been accounted for. As noted above, what happens at Alaska airports impacts the entire community, unlike many airports in the lower 48.

A Construction Safety and Phasing Plan (CSPP) is prepared during design and details require items to configure the runway for safe operations including closure phases, temporary marking layouts, lighting, and required notifications and coordination with FAA and stakeholders. Multiple FAA business lines review the CSPP before the project begins. If the FAA approves half-width operations, the CSPP provides a road map for the contractor detailing how to implement the half-width construction, while understanding their work limitations and airfield operations.

 

Half-width airport runway construction in action

With the FAA’s approval, we’re working with communities from Barrow—recently renamed Utqiagvik—to Kotzebue and (almost) to Russia to keep airport operations open using the half-width method.

Ralph Wien Memorial Airport in Kotzebue features the shortest runway servicing Alaska Airlines passenger traffic—just 6,300 feet long. The 150-foot-wide runway is essentially surrounded by water—on three sides by the Kotzebue Lagoon and on its other side by Kotzebue Sound. Our team completed the Kotzebue project in 2014.

 

The Wiley Post-Will Rogers Memorial Airport in Utqiagvik (Barrow) is in the northernmost US city and sits near the Chukchi Sea. Without a parallel taxiway to repurpose as a runway, aircraft will take off and land on a half-width runway during the 2020 rehabilitation of the runway.

 

The Wiley Post-Will Rogers Memorial Airport in Utqiagvik is a bit longer than the Kotzebue airport at 7,100 feet, but it has its own set of challenges. The airport is in the northernmost US city and sits near the Chukchi Sea. It frequently has its aircraft operations impacted by seals or polar bears taking up residence on the runway. The project is scheduled for construction in 2020.

What the two airports have in common is their need for scheduled and reliable jet aircraft operations and their lack of a parallel taxiway to use as a temporary runway. What we did at Kotzebue, and will repeat at Utqiagvik, is provide temporary markings to clearly define the active half of the runway, along with temporary lights along its edge to further focus the pilot away from the work area. During the nighttime construction, illuminated, flashing runway closure markers marked the runway fully closed while the contractor milled the existing surfaces and repaved the airport. Once the first half of work was completed, the contractor painted new temporary markings on the opposite side and the process was repeated.

Gambell Airport is much smaller, with a 100-foot-wide runway on St. Lawrence Island, roughly 60 miles from Siberia Russia and 175 miles from mainland Alaska. (Some smaller airports have preconstruction runway widths as narrow as 60 feet.) Jet aircraft don’t land at Gambell, but for the community’s 680 residents, the airport is its connection to the greater world, as regular flights provide the village with groceries and other essentials.

We followed the same process at Gambell during the 2018 construction season to resurface the island airport’s runway for the first time since 1985. With 33 years between enhancement projects, it’s essential that this work is completed effectively as well as safely.

 

Safety first—it’s the reason for the rules

Safety is the bottom line for all airport operations—regardless of airport size or location. And it’s the first thing we consider when designing a runway rehabilitation and/or enhancement. Here’s a motto we live by: If you’ve seen one airport, you have only seen one airport. It’s essential for a seasoned airport designer to consider all the unseen and unique operations for a specific airport. Along with valued input from all the stakeholders, we can propose a safe and effective development solution.

So, when it’s time to rehabilitate the dozens of single-runway airports spread across thousands of miles of Alaska wilderness, we must design with safety in mind for both aircraft and construction activities. In our unique setting, the FAA understands and supports our approach, and we’re always excited to see a community’s connection to the outside world enhanced. We just do it one-half at a time.

About the Author

Johnathan Limb

Johnathan Limb is an Anchorage, Alaska-based civil engineer and aviation expert. He was recently selected as one of the top young professionals in the Northwest by Engineering News-Record (ENR) magazine.

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