11.   The chief designer of its turbine blades is Dan Somers, a former NASA engineer whose wing airfoils are now standard for many small airplanes.

12.   The cracks are in the steel ring hidden deep in the engine between spinning turbine blades, and they can lead to total engine failure.

13.   The machines have created prototypes for NASA helmets, turbine blades for jet engines and cellular phones.

14.   The stereolithography machines have created prototypes of NASA helmets, turbine blades for jet engines, windshield wipers, high-tech chairs and cellular phones.

15.   The unit makes turbine blades and castings for aircraft makers.

16.   Then, rising as a swarm, they would be sucked into jet engine air intakes, their bodies fracturing the whirling turbine blades.

17.   Turbine blades are attached to the spool, and, if it cracks, it can throw metal parts out of the engine at high velocity.

18.   Two newspapers reported that the Federal Aviation Administration had sent out advisories warning of possible cracks in the turbine blades of Learjet models like the one that crashed.

19.   Weakened engine mounts, bad turbine blades, defective cargo doors.