MV-22 Ospreys and KC-130J Hercules are parked during Marine Rotational Force - Darwin trans-Pacific flight, Cassidy International Airport, Kiribati, Sep. 19, 2019. The flight was conducted to improve upon the Osprey trans-Pacific concept that has been developed and refined over the past three MRF-D iterations. - MV-22 Ospreys and KC-130J Hercules are parked during Marine Rotational Force - Darwin trans-Pacific flight, Cassidy International Airport, Kiribati, Sep. 19, 2019. The flight was conducted to improve upon the Osprey trans-Pacific concept that has been developed and refined over the past three MRF-D iterations.