US aviation regulators will inspect four Boeing 787s amid concerns over production flaws in the jet, the Federal Aviation Administration (FAA) told AFP on Thursday.

Manufacturing defects on the 787 were discovered last year, prompting Boeing to suspend deliveries of the model in November, adding to the crises faced by the struggling aviation giant.

"The FAA is taking a number of corrective actions to address Boeing 787 production issues. One of the actions is retaining the authority to issue airworthiness certificates for four 787 aircraft," the regulator said.

"The FAA can retain the authority to issue airworthiness certificates for additional 787 aircraft if we see the need."

Issuing airworthiness certificates is usually handled by Boeing employees who inspect the planes under an agreement with the regulator, though the FAA said its inspectors do occasionally examine planes themselves.

Boeing announced last September that it had discovered defects in a fuselage joint and the horizontal stabilizer, and launched an investigation into the defects.

The company has struggled with the global drop in travel demand caused by the Covid-19 pandemic, and the after-effects of the 20-month grounding of its best-selling 737 MAX jet, which has returned to the skies in recent months.

Boeing said new orders overtook cancelations last month for the first time since November 2019. The company aims to resume production of the 787 this month but at the slower rate of five per-month rather than the usual 10.

"We are encouraged by the progress our team is making on returning to delivery activities for the 787 program," a Boeing spokesperson said.

"We have engaged the FAA throughout this effort and will implement their direction for airworthiness certification approval of the initial airplanes as they have done in the past."