Definition
A written agreement between two or more parties — typically agencies, organizations, or operators — that records a shared understanding of roles, responsibilities, or procedures. In aviation, an MOU is commonly used between the FAA and other entities (such as the military, airport operators, or law enforcement) to formalize cooperative arrangements that are not full contracts but still carry operational weight.
Plain English
A written document where two groups put in writing what they have agreed to do, who is responsible for what, and how they will work together.
Context Anchor
Pilots may see MOU in FAA material, airport procedures, training program documents, or agreements involving airport operations and air traffic coordination.
Derivation
From Latin 'memorandum' (a thing to be remembered) and 'understanding' (a shared agreement). Together it literally means 'a written note of what has been agreed' — which is exactly what it does.
Why Pilots Care
Some procedures pilots follow — especially around military operations areas, joint-use airports, or special agreements — exist because of an MOU. Knowing the term helps when reading regulatory or operational documents that reference one.
Intuition Check
Do not read understanding here as just people knowing about something. In this term, it means a documented agreement between parties.
Example Sentence 1
An MOU between the FAA and the U.S. Air Force defines how civilian and military traffic share the airspace around the joint-use airfield.
Example Sentence 2
An MOU between the military and civil aviation authorities established shared use of certain airspace.