By Yereth Rosen
ANCHORAGE, Alaska (Reuters) - Rescue teams were searching the waters of southeast Alaska for two passengers missing after a pair of sightseeing planes crashed in midair, killing at least four people, the U.S. Coast Guard said on Tuesday.
The two missing people, an Australian and a Canadian, were among 14 passengers from a Princess Cruises ship who boarded two seaplanes operated by separate tour companies in the town of Ketchikan, the cruise line said. No further information about the missing was made available.
Ten people survived but were injured in the collision, which took place over open water during daylight hours on Monday, the Coast Guard said. At least four, including one of the pilots, were killed. The victims were not immediately identified.
The water temperature off Ketchikan on Tuesday was 48 degrees Fahrenheit, according to the National Weather Service. Expected survival time in 40 to 50 degree (4-10 C) water is one to three hours, according to the United States Search & Rescue Task Force website.
"At this point there is a variety of factors that go into survivability," Coast Guard Chief Petty Officer Matthew Schofield said. "But the reality is that Alaskan waters are very cold."
Tuesday's search for the two missing passengers involved a Coast Guard helicopter, a flotilla of boats and teams from the U.S. Forest Service, U.S. Fish and Wildlife Service, Ketchikan Fire Department and other rescue units, Schofield said.
The effort will continue "until we have exhausted all chance of finding anybody," he said.
All of the planes' passengers arrived in Ketchikan on the cruise ship Royal Princess during a seven-day trip between Vancouver and Anchorage, Princess Cruises said.
Ten passengers and a pilot were aboard one float plane, a de Havilland Otter DHC-3, operated by Taquan Air. Four passengers and a pilot were aboard the second float plane, a de Havilland DHC-2 Beaver, run by Mountain Air Service of Ketchikan.
The crash site, at Coon Cove about 300 miles (480 km) south of Alaska's capital, Juneau, lies near a tourist lodge that runs excursions to the nearby Misty Fjords National Monument.
Ketchikan-based Taquan Air said the plane was returning from a sightseeing tour of Misty Fjords when the crash occurred.
The National Transportation Safety Board sent a team of at least 10 people headed by lead investigator Aaron Sauer, said NTSB spokesman Keith Holloway.
(Reporting by Yereth Rosen in Anchorage; additional reporting by Rich McKay in Atlanta and Barbara Goldberg in New York; Editing by Scott Malone and Cynthia Osterman)