Juneau airport officials say they want traditional runway safety improvements and not engineered plane-slowing systems like those envisioned by federal regulators in a new study.
An environmental study of improvement options, released Monday by the Federal Aviation Agency, presents five strategies to bring Juneau International Airport's safety area up to federal standards. Generally the government requires a safety area 100 feet in length and 500 feet in width around a runway.
Three of the five options involve installing an engineered-materials arresting system (EMAS), a technology the FAA said would limit environmental disturbance but that Juneau officials said might fail in the city's climate. The system consists of pre-cast, cellular cement blocks installed at the ends of runway. The blocks would crush under an aircraft's weight, causing it to slow.
"EMAS is more expensive to build and maintain," said Ron Swanson, chairman of the Juneau International Airport Board. "It's not supposed to get wet. Anyone who knows Juneau's climate knows it will be difficult."
The report acknowledges Juneau airport officials' concerns but says the system is safe.
"The EMAS is sensitive to disturbance by equipment, and in particular can be damaged by maintenance equipment," according to the draft environmental impact statement. "Specialized snow removal equipment would be needed since the EMAS may at times have to be cleared of snow and slush to prevent ice buildup."
The manufacturer of the arresting system said it works effectively with less than an inch of ice build-up.
Building runway safety areas with EMAS costs more than traditional filling and grading, Swanson said.
One $18.7 million option would extend the safety area 200 feet into the Mendenhall Wetlands State Game Refuge on the runway's west end. The runway safety area would be 600 feet long, with 337 feet made of arresting cement blocks and the rest standard gravel.
A $17.9 million option would extend the safety area 368 feet into the refuge at the runway's east end.
Another alternative would place the arresting system at the west end of the runway and a standard runway at the east end. That option costs $13.9 million.
Swanson said the board prefers traditional runway safety areas.
Two traditional options are available in the report.
One alternative creates more than 700 additional feet of 500-foot-wide safety areas at each runway end. This proposal, which costs $10 million, would reroute the Mendenhall River. The other option, at $9.4 million, would shift the runway 618 feet to the east so it doesn't require rerouting the river.
All of the five options proposed by the FAA would require relocating the emergency vehicle access road or Dike Trail to the west, but the extent varies in each of the alternatives. All five proposals would also relocate Duck Creek to enter the Mendenhall River north of its current discharge point.
The FAA will conduct community meetings at Centennial Hall on June 1 and 2 to get public input.
I-Chun Che can be reached at email@example.com.
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