The state police helicopter which crashed into the Harvard Yacht Club in February, killing four on board, had contaminants in its fuel system that may have caused the motor to fail, a federal official told reporters at a press conference yesterday.

Dennis L. Jones, director of the Northeast Regional Office of the National Transportation Safety Board (NTSB), said federal investigators had found impurities, which they have yet to identify, in the wreckage of the helicopter's engine but are still uncertain about the cause of the crash.

"We have found some evidence of fuel contamination," Jones said. "We are nowhere close to a probable cause," he added later.

Jones said that the amount of contaminant was "relatively small" but significant enough that it would have affected fuel flow, possibly leading to a malfunction. Although investigators have yet to determine the substance's exact chemical composition, Jones described it as a "hard material, quite visible" to the naked eye.

In an article in Thursday's Boston Herald, anonymous sources said they were certain that someone had introduced the substance, which was described as a liquid, resin-based adhesive, into the helicopter's fuel tank.

"Whether it was accidental, I highly doubt it," one source told The Herald.

But Jones denied that there was any reason to believe, at least at this stage, that the helicopter's fuel tank had been sabotaged.

"We don't have any evidence whatsoever that foul play is involved," Jones said.

The police helicopter, a Eurocopter AS-350B, plunged from the sky and tore through the roof of the HarvardYacht Club on February 22. The passengers, twostate police pilots and two American Telephone andTelegraph (AT&T) technicians, died in the impact.The AT&T employees were being taken from Boston toNorfolk airport in order to do work for a statecontract.

The crash severely damaged the floatingbuilding, which houses boats for Harvard men's andwomen's sailing teams. Since then, the teams havesailed out of the boathouse of the MassachusettsInstitute of Technology sailing teams.

The Investigation

Initially, authorities expected theinvestigation to take six months, Jones said. Hesaid it is unclear when conclusive findings aboutthe cause of the crash will finally be available.

But Jones said that investigators are "close"to determining the exact chemical composition ofthe impurities. The next step is ascertaining thesource of the contaminant, he said.

Authorities are currently examining the fuel'squality, the sites where the fuel was stored andthe possibility of by-products resulting fromchemical processes in the engine, Jones said.

Maintenance problems may possibly have led tothe build-up of contaminants in the fuel system,Jones said.

In spite of the discovery of contaminants,Jones said investigators have in no way ruled outother possible causes for the crash, includingpilot error, mechanical failure and weather.

Investigators still do not know whether thehelicopter's transmission indicator lit up beforethe crash.

A light on the indicator would mean that piecesof transmission gears may have begun to clog thehelicopter's motor in the crucial moments beforethe pilot lost control.

But according to The Associated Press, apreliminary report by the NTSB confirmed that thehelicopter's flight controls and transmission wereworking properly before the crash. The report alsosaid that witnesses saw a puff of smoke comingfrom the helicopter in its descent.

Criminal Investigation?

Anonymous sources told the Boston Herald thatthe Middlesex Country district attorney's officeis ready to begin a criminal investigation intothe fuel contamination.

But a spokesperson at the office said thatDistrict Attorney Thomas Reilly declined tocomment, and Jones would not comment on thedistrict attorney's involvement in theinvestigation.

Jones said that if the investigators foundevidence of criminal activity behind the crash,the investigation would be turned over to thedistrict attorney's office.

Helicopter flight and maintenance personnelwould be the only ones in a position to tamperwith the fuel, Jones said, although authoritiesare considering whether outside individuals mayalso have had access.

There were two places where the helicoptercould have received its fuel, Jones said, thestate police flight wing's offices in Norwood andanother fuel center in the area.

Jones said yesterday that he personally has notseen any incidents of sabotage through fuelcontamination in the 300-plus plane crashes he hasinvestigated in his 15-year career. But he saidthat finding fuel contamination as the cause ofaccidents is "nothing new" to the NTSB.

Jones said authorities are still investigatingwhether the problem is one intrinsic to this modelof helicopter.

"We want to make sure other helicopters aresafe," Jones said. "We're looking at the history[of the helicopter]."

The Eurocopter A350B has been involved in 63accidents in the United States, killing 57on-board passengers, according to NTSB records,and averages 3.5 accidents per 100,000 hours offlight.

Jones also dismissed assertions in The BostonHerald's article that Federal AviationAdministration (FAA) had been asked to withdrawfrom the probe several weeks ago and thenreinstated several hours later.

He said that the FAA never left theinvestigation and praised the cooperation betweenthe agencies.

The NTSB is leading the federal investigation,which also includes the FAA, the MassachusettsAeronautics Commission, the state police andEurocopter and Turbomecha, the manufacturers ofthe helicopter and the engine