Coast Guard crews continued their search overnight for the missing pilot of a mail cargo plane that crashed into the ocean yesterday about seven miles southeast of Lihu'e.

The Alpine Air pilot, identified by sources as Paul Akita, 38, of O'ahu, was alone in a twin-engine turboprop Beechcraft King Air 1900 that was carrying about 4,200 pounds of mail on a regularly scheduled flight between Honolulu and Kaua'i. The plane departed at 4:43 a.m. and was scheduled to arrive at Lihu'e at 5:15 a.m., according to Ian Gregor, spokesman for the Federal Aviation Administration Western-Pacific Region.

The plane disappeared off radar at 5:08 a.m. about 7.2 miles southeast of Lihu'e when it was flying about 100 feet above the water, Gregor said. Aircraft heading toward Lihu'e typically would be flying at an altitude of 1,500 feet at that distance from landing, he said.

The aircraft was reported missing when it did not arrive on time. No mayday signal was received, and the pilot was not in contact with air traffic controllers during the flight, Gregor said.

The plane was equipped with an emergency locating transmitter, which normally activates upon impact, but authorities did not receive a signal, according to Coast Guard Lt. John Titchen.

At 8:50 a.m., crew members aboard a 25-foot boat from Coast Guard Station Kaua'i spotted debris on the surface in 2,500 feet of water, Titchen said. A Coast Guard C-130 plane confirmed the debris sighting two minutes later, and parts of the aircraft, 15 bags of mail and an inflated life raft were retrieved, he said.

Alpine Air station manager David Dart said the company "is hoping for the best."

"We're still praying for a successful conclusion for the pilot. He's good waterman, so there's still a chance," he said.

Akita has been working off and on for Alpine Air for about three years, and at times works as a surf instructor for Hawaiian Fire surf school.

"He's a great guy, a local boy, surfer. He's a cheerful, clean-cut, hard-working guy, just like all the highly trained, hard-working guys we have working for us," Dart said.

"It's just a shock to the aviation community when something like this happens. You try everything you can to make sure this situation doesn't occur, but sometimes it just happens."

Akita is not married, but has a mother and girlfriend, Dart said.

He is listed as a distinguished alumnus of the Honolulu Community College Pacific Aerospace Training Center's commercial aviation program on the school's Web site. Officials there declined to comment yesterday.

Ryan Miller, operations manager for Hawaiian Fire, said the Japanese-speaking Akita last worked for the surfing school about a year ago and is still on the company's roster of instructors. "He really wanted to make it as a pilot. That's his main passion," Miller said.

Titchen said searchers had covered a 100-square-mile area by late yesterday afternoon and that a HH-65 Dolphin helicopter, the 87-foot patrol boat Kittiwake out of Nawiliwili and the 225-foot buoy tender Walnut were to continue the search overnight and today.

He said conditions were "treacherous," with winds of 25 knots and 20-foot seas.

Gregor said the FAA and National Transportation Safety Board are investigating the accident.

Alpine Air is subcontracted by Postal Service contractor Corporate Air to fly mail to several destinations within the state, including Moloka'i, Kalaupapa, Lana'i and Waimea on the Big Island, according to Postal Service spokesman Duke Gonzales.

Any salvageable mail retrieved from the ocean will be delivered, Gonzales said. The cargo was likely a mix of mail from Hawai'i, the Mainland and international points, he said.

Alpine Air is part of Provo, Utah-based Alpine Air Express, the nation's third-largest regional cargo airline.

Its Hawai'i operation uses four Beechcraft 1900 and five Beechcraft 99 cargo aircraft to provide regularly scheduled Postal Service air cargo service.

Gonzales said there are two to three mail cargo flights a day to Kaua'i, and that an earlier flight yesterday morning operated without incident.

Kaua'i-bound mail is flown over in the early morning, and afternoon flights bring Kaua'i mail to Honolulu, Dart said.

Gonzales said that although the missing pilot isn't a Postal Service employee, "he played a vital role in ensuring the delivery of the mail to our customers."

The Postal Service pays loss or damage claims when mailed items are shipped via insured, registered, COD or Express Mail services. Customers who believe they have a claim may go to a post office and file a Form 1000 claim requesting reimbursement.

Customers must provide proof of mailing, loss and evidence of value as documentation with their claims. Gonzales said postal clerks can provide them with the form and answer any questions they have regarding its filing and insurance claim procedures.

Postal customers expecting mail that is not eligible for a claim should wait several days for delivery, then contact the sender if the anticipated mail is not received, he said.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.