Federal air-safety regulators have stripped Boeing Co.’s authority to inspect and sign off on several newly produced 787 Dreamliners, part of heightened scrutiny of production issues that have halted deliveries of the popular wide-body jets. The Federal Aviation Administration stated that its inspectors, rather than the plan maker’s, would undergo routine pre-delivery safety checks of four Dreamliners that Boeing has been unable for months to hand over to its airline clients while it grapples with various quality lapses.The agency has long empowered Boeing to perform the final safety sign offs on the FAA’s behalf, allowing it to issue what are known as airworthiness certificates required to hand over new jets to airlines. The FAA said it has withheld the same authority on some of the planes in previous years to keep inspectors’ skills up to date. Now, the FAA stated that its move to withhold final-approval authority was part of a wider set of actions directed at Boeing’s 787 production problems. A spokesman stated that the agency could decide to have its own inspectors sign off on more Dreamliners. “We can extend the retention to other 787 aircraft if we see what we need,” he stated.