Uh-1H captain reported the right side cargo door departed the aircraft in cruise flight.

Attributes
ACN	1547767
Time
Date	201806
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Iroquois (Huey) All Series Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	None
Component
Aircraft Component	Cargo Door
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Commercial
Experience	Flight Crew Last 90 Days 35 Flight Crew Total 2400 Flight Crew Type 2000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural FAR

Narrative:

During cruise flight; the right hand cargo door inadvertently left the aircraft. The aircraft experienced a 'thump' with no other indications. The aircraft landed safely as scheduled. Upon post-flight; it was discovered that there was damage to the main rotor blade. [There were] no injuries to passenger or crew.

Original NASA ASRS Text

Title: UH-1H Captain reported the right side cargo door departed the aircraft in cruise flight.

Narrative: During cruise flight; the right hand cargo door inadvertently left the aircraft. The aircraft experienced a 'thump' with no other indications. The aircraft landed safely as scheduled. Upon post-flight; it was discovered that there was damage to the main rotor blade. [There were] no injuries to passenger or crew.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.