Dutch aviation investigators completed a yearlong investigation Thursday by squarely blaming Boeing Co. for last year's crash of an El Al 747 cargo jet.

Forty-three people, most of them on the ground, died when the cargo jet plowed into an apartment complex on the outskirts of Amsterdam on Oct. 4, 1992, in one of the worst urban air accidents in aviation history.The 747 lost its two right wing engines and plunged to earth about 15 minutes after taking off for Tel Aviv, Israel, from Amsterdam's Schiphol Airport.

In a report presented at a two-day public hearing on the investigation, Henk Wolleswinkel, chief of the Dutch Aviation Inspectorate, said the crash was caused by a design flaw in the pylon assembly that holds the engines under the wing.

Barry L. Eberhardt, a Boeing official, told the panel that "Boeing has total agreement with the report."

Christopher Villiers, a Boeing spokesman, said the company has been unable to correct the design flaw, but has asked airlines to increase inspections of the pylons.

Investigators said many questions surrounding the crash remain unanswered.

"The investigation can be compared to putting together a puzzle with nearly half the pieces missing, and those that are present are for the most part seriously damaged," the report said.

In the event of a serious engine malfunction, the pylon is supposed to cleanly release the engine, allowing the plane to fly further on the remaining engines.

But in the El Al crash, the inside right engine tore the wing's forward edge and smashed into the outside engine as it broke off. The impact caused the outer engine to break from the wing as well, forcing the pilot to lose control.

"The concept of the clean breakaway from the pylon ought to be re- evaluated," the report said.

Although Boeing has claimed in the past that the 747 can fly on two engines, the report said the engine breakaway also impaired the hydraulic and electronic systems needed to steer the craft.

The report said there was no evidence of sabotage or bird damage.