Many questions about Friday's islandwide power outage will remain unanswered until Hawaiian Electric Co. completes its investigation into the cause of the system shutdown, with a report expected in the next few days.

Meanwhile, one bleak image from those powerless hours stands out: that of travelers stranded in a dark Honolulu International Airport. Even with the help of emergency generators, the state's flagship air transit facility was not up to the task. That must change.

Keeping the airport functioning is key to public safety: It is Hawai'i's lifeline; it's crucial that people be able to come and go, especially during times of emergency.

Further, a darkened, hobbled airport is not the sight any city — certainly not one that calls itself a visitor attraction — wants its tourists to see, if it is at all avoidable.

And it is avoidable: The state published an environmental report in August for an airport emergency power facility. Robbie Alm, HECO executive vice president, said it would produce 10 megawatts of electricity once its first phase goes live late in 2010.

That timetable was set after the calamitous power failure following the 2006 earthquakes. This second major blackout a mere two years later proves that there's no time to waste in bringing this plan to reality.

According to the report, the emergency power currently available at the airport only provides backup for critical operations: airfield lighting, emergency exit lighting in terminals, the Emergency Operations Center, communication and fire-protection systems.

While those capabilities certainly comprise the bottom-line duties, any international airport serving an A-list tourist destination should be fully functional as much as possible.

And "fully functional" was not how the Denver-bound Bauman family would have described their airport encounter. They were among the hundreds who waited for hours at night trying to get out.

With Hawai'i in the position of competing for every crucial tourist dollar, that's surely not the kind of image anyone wants to project.

The airport plan sounds worthy of the projected $25 million in construction costs, particularly because it would be done as a partnership. The state would build it and own it, and HECO would cover much of the planning costs and would operate and maintain it.

It's a win-win for the state and the utility, which would be able to use the extra power to supplement the capacity of its own grid, if needed.

While the arrival of a new startup unit next summer will increase reliability, Alm added that his company and state transportation officials will look for ways to fast-track the airport project, too.

That's a sensible course. The state needs a robust airport system, not one that makes Hawai'i seem disconnected from the world.