Minneapolis ? Reports filed by federal aviation inspectors during the first month of a strike by Northwest Airlines Corp.’s mechanics challenge assertions by executives that operations are running smoothly, according to a newspaper’s review of the records.

In a story for Sunday’s editions, the Star Tribune newspaper reported that the inspection records – which were reviewed by two independent aviation experts – describe training deficiencies among replacement workers, thin staffing, maintenance blunders and mistakes in recording aircraft repairs.

It cites one incident in which mechanics failed to find a dead bird in the engine of a jet about to leave Memphis, Tenn., but a co-pilot spotted it before takeoff.

In another case, it said inspectors watched replacement workers in Philadelphia work through the night to replace a brake. That job normally takes experienced mechanics less than three hours, the experts said.