The Federal Aviation Administration has approved Boeing’s proposed solution to bring its MD-11 planes back to the sky. The FAA grounded the MD-11 and its predecessor the DC-10 after a deadly UPS crash in November, which saw an engine break free from the cargo plane’s wing. The crash killed three UPS crew members on board and 12 others on the ground. It also left the MD-11’s future uncertain. The McDonnell Douglas plane, which Boeing took responsibility for when it merged with the company in 1997, was already being replaced with newer, more fuel-efficient models and many in the industry wondered if the FAA’s grounding would mean a hurried retirement for the entire fleet .  UPS and FedEx already planned to retire their MD-11s over the next several years and the crash prompted UPS to accelerate its plans, announcing in January that its MD-11s would not return to service. On Monday, spokespeople for the FAA, Boeing and FedEx said the grounded plane now had a path forward.…