Pinnacle Airlines (Memphis International) has filed for chapter 11 bankruptcy protection to reorganize and implement a more extensive turnaround plan. It had previously already closed down subsidiary Mesaba Airlines (Minneapolis St. Paul International) and now has announced plans to gradually phase out all turboprops operated by Colgan Air (Boston) and to eventually close down Colgan altogether by November. Colgan Air currently operates 29 Saab 340Bs and 31 DHC-8-400s on behalf of United Airlines (UA, Chicago O'Hare) and US Airways (Phoenix Sky Harbor) as United Express and US Airways Express. It is expected that some of the Dash 8-400s might be operated by another carrier on behalf of United Airlines going forward. US Airways had already been planning to stop using its two remaining Saab 340s operated by Colgan Air later this summer anyway. Pinnacle has received 74.3 million USD in debtor-in-possession financing from Delta Air Lines (DL, Atlanta Hartsfield Jackson) to support its reorganization plans that will see the airline flying exclusively for Delta from the end of the year.