Water in Fuel, Excess Weight Found in Crash : Air disaster: A sky-diving plane that carried 16 to their deaths was 1,600 pounds over limit, investigator says. Fluid was enough to disable an engine, he adds.

A sky-diving plane that crashed during takeoff in Riverside County last week, killing 16 people and injuring six others, was more than 1,600 pounds over its maximum allowable takeoff weight under existing flight conditions, a federal investigator said Wednesday.

A. Don Llorente, air safety investigator for the National Transportation Safety Board, also said that authorities found five gallons of water contaminating the tank that fed fuel into the aircraft’s right engine.

The plane, a De Havilland DH-6 Twin Otter, crashed April 22 after the right engine failed, authorities have said.

The water--probably pumped into the tank with fuel just before the ill-fated takeoff--was of sufficient amount to disable an aircraft engine, Llorente said. It might have come from condensation in a storage tank, he said.

Llorente declined during a press briefing at NTSB headquarters in Gardena to speculate on the cause of the crash, saying that that determination will be made when the board completes its report in six to nine months.

Including passengers and crew, Llorente said the aircraft was carrying an estimated 11,556 pounds, compared to a limit of 9,900 pounds under the flight conditions.

The allowable weight is lower when an aircraft lacks a so-called “auto-feathering” device, as the Twin Otter apparently did, Llorente said. The device is designed to increase aircraft control and improve maneuverability in the event of engine failure.

Although the aircraft was permitted to fly without the feathering device, Llorente said, the lack of the mechanism lowered the legal weight limit for the flight from a maximum of 11,579 pounds to 9,900 pounds.

The aircraft, built in 1968, once had an auto-feathering device, Llorente said, but it became disabled before the owner, Perris Valley Aviation Services, purchased the twin-engine plane. The plane was previously owned by a company in the Central American nation of Honduras, Llorente said.

The aircraft had logged 29,341 hours of flying time as of March, its last inspection period, Llorente said. He could provide no details on the inspection.

Investigators are trying to determine how the aircraft fuel became contaminated with water.

However, Llorente said authorities suspect that contamination occurred as fuel was being transferred from a tanker truck to the aircraft. The truck’s filtering system apparently was unable to separate the water from the fuel, Llorente said.

And because of a mechanical failure in the Perris Valley Airport’s pumping system, Llorente said, workers had to siphon the fuel into the truck from an underground tank.

The investigation is continuing, Llorente said, and its initial phase--which may give a preliminary cause of the crash--is expected to continue for at least two weeks.

The crash at the airport in rural Riverside County killed 16 people, including veteran instructors, international sky divers and a number of camera operators. Six others on board were seriously injured.

The small airport is a national center for sky-diving enthusiasts.

Investigators previously found that the jumpers were not wearing safety restraints as required by law.

Despite the impact of the crash, investigators said that the fuel tanks did not rupture, allowing authorities to inspect the fuel.