Boeing’s Charleston, South Carolina 787 factory has experienced a higher number of behind-schedule jobs involving the airplane’s mid-body section than originally anticipated, requiring it to apply “additional resources” to help flow times progress to a satisfactory level, Boeing CFO Greg Smith acknowledged during a conference call the company held Wednesday to discuss its fourth-quarter earnings. Smith attributed the difficulty to the simultaneous introduction into production of the 787-9 and an increase in rate from seven to 10 Dreamliners per month. On January 24 Boeing announced that it had rolled out the first 787 at the 10-per-month rate.

“The most significant structural change in the airplane going from a Dash eight to a Dash nine is in the mid-body,” said Smith. “So to address this we’ve applied additional resources; we know how to do this, and we’ll get those jobs back to what we feel is an acceptable level.”

Last week the Wall Street Journal reported that Boeing has decided to immediately hire 300 contract mechanics and inspectors in Charleston and is considering adding another 200 to 700 to help the some 7,000 permanent employees improve flow times. Critics of Boeing’s decision to supplement 787 production in Everett, Washington, with the new Charleston factory have long pointed to the South Carolina’s workers’ lack of experience as a potential pitfall.

Smith, however, expressed satisfaction with the improvement the plant has shown lately. “Certainly, when you look at flow time, when you look at unit cost at Charleston, whether it’s final, mid or aft, it made great progress and the team has been very focused on continuing that progress,” noted Smith. “This is all part of bringing this program up to a widebody rate that has never been done and they’re doing it successfully. But there’s going to be points in the production system where you’re going to have to put additional resources from time to time, and this just happens to be one of them.”