Twin Otter DHC-6-300
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 30; Flight Crew Total 6900; Flight Crew Type 950
Workload; Troubleshooting
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Aircraft Aircraft Damaged; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed As Precaution; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft; Procedure
On the initial climb out of ZZZZ to ZZZ1 we received a DOORS UNLOCKED annunciation light. We were at 700 feet AGL over the bridge. Looked through the cabin to see that the cargo door had opened. At that time the co-pilot went to the cargo hold to secure the door. He was unsuccessful due to no interior handle on the door. After passing the bridge the co-pilot returned to the flight deck and reported that the door had detached and fell into the ocean. There were no adverse effects to the flight characteristics of the aircraft. We continued the visual approach to ZZZZ1. I did not ask for priority handling and landed without further issues.
Captain reported cargo door departed the aircraft in flight and continued to destination airport.