Sarah MacDougal Lieutenant commander Sarah MacDougal was one of the chief engineer s aboard the in 2364 . After the " Enterprise " crew became infected with the polywater intoxication virus , causing them to lose control of their ability to inhibit their emotion s and behavior , Wesley Crusher tricked MacDougal out of main engineering so he could take control of the area . The young Crusher then erected a force field , separating himself from the rest of engineering and preventing MacDougal or anyone else from entering the main control room . MacDougal subsequently assisted Commander Riker in disabling the force field and take back control of the starship . Afterward , MacDougal tried to replace the isolinear chip s removed by her infected colleague , Jim Shimoda . With the chips removed , the ship could not be controlled , which was made more crucial as the ship was on a collision course with a stellar core fragment . Data , though himself infected , was able to place the chips back more quickly , regaining ship control and avoiding a collision . She appeared to be unaffected by the intoxication as she was able to perform her duties without interruption . However , she was injected with the antidote . ( ) Under Chief Engineer Geordi La Forge , MacDougal was a duty engineer . She , along with Leland T . Lynch , were supervisors for the third shift . During the upgrade of the subspace phase coil s , their team performed the final calibration needed to complete the procedure . In her final analysis , MacDougal noted a minor phase variation in the tertiary harmonics . This variation didn ' t affect the power output ; however , Argyle recommended the continued use of test instrumentation for monitoring phase shifts . ( ) Appendices . Background information . Sarah MacDougal was played by Brooke Bundy . MacDougal appeared to have been replaced as chief engineer by Lieutenant Commander Argyle in , also set in 2364 , as she was not seen , heard , or mentioned after . However , Commander William Riker claimed that he , as first officer , was the supervisor to maintenance of the ship ' s engines . He went on to say that he was guided by " one of our chief engineers : Lieutenant Commander Argyle , in this case " , which supports that MacDougal was not replaced . The novelization of " Encounter at Farpoint " also has Argyle as chief engineer even though Bundy appeared in early audition footage . The practice of having more than one chief engineering officer on the " Enterprise " came to an end in 2365 . Riker ' s involvement with main engineering lessened as well , once Geordi La Forge , a bridge officer , became chief engineer . For the remaster ed edition of " Galaxy ' s Child " , the original okudagram for the engineering logs was replaced by a new graphic . MacDougal was mentioned in this new graphic . Her first name Sarah comes from the script . Apocrypha . In the novel " The Buried Age " and the short story " Meet with Triumph and Disaster " in " The Sky ' s the Limit " , she was described as having served as one of the USS " Enterprise " - D ' s two chief engineers under Captain Thomas Halloway in 2363 , splitting her duties with Argyle . " The Buried Age " referred to her as Heather MacDougal . MacDougal has appeared or been mentioned in other non - canon releases , such as Pocket TNG novel " Ghost Ship " , and " " comics from DC . In " Suspect " , it was noted that she had been killed sometime between 2369 and 2371 . Alternatively , the novel " A Time for War , A Time for Peace " establishes that MacDougal " retired " from Starfleet .