April 15 (Reuters) - Boeing ( BA ) said on Monday it has

not found fatigue cracks on in-service 787 jets that have gone

through heavy maintenance, as the planemaker defended the

twin-aisle aircraft program ahead of a U.S. Senate hearing on

Wednesday.

Last week, a Boeing ( BA ) whistleblower alleged that the company

dismissed safety concerns about the assembly of its 787 and 777

jets that fly international routes. The whistleblower, Boeing ( BA )

quality engineer Sam Salehpour, is set to testify in the Senate

hearing on the company's safety culture.

Salehpour has claimed that Boeing ( BA ) failed to adequately shim,

or use a thin piece of material to fill tiny gaps in a

manufactured product, an omission that could cause premature

fatigue failure over time in some areas of the Boeing 787

Dreamliner.

His claims, which are being investigated by the U.S. Federal

Aviation Administration (FAA), include remarks that he saw

workers "jumping on the pieces of the airplane to get them to

align."

Boeing ( BA ) has been grappling with a full-blown safety crisis

that has undermined its reputation following a Jan. 5 mid-air

panel blowout on a 737 MAX single-aisle plane.

On a call with reporters on Monday, two senior Boeing ( BA )

officials said there were zero airframe fatigue findings among

the near 700 in-service Dreamliner jets that have undertaken

heavy maintenance inspections after six years and 12 years.

"All these results have been shared with the FAA," said

Steve Chisholm, Boeing's ( BA ) chief engineer, mechanical and

structural engineering.

Boeing ( BA ) halted deliveries of the 787 widebody jet for more

than a year until August 2022 as the FAA investigated quality

problems and manufacturing flaws.

In 2021, Boeing ( BA ) said some 787 airplanes had shims that were

not the proper size and some aircraft had areas that did not

meet skin-flatness specifications.

The 787, which was launched in 2004, had a specification of

five-thousandths of an inch gap allowance within a five-inch

area, or "the thickness of a human hair," said Lisa Fahl, vice

president of Boeing Commercial Airplanes airplane programs

engineering.

She said reports of workers jumping on plane parts were "not

part of our process."