Definition
An RNAV path-and-terminator leg coded as a holding pattern that continues until the pilot manually terminates it. The aircraft flies the published holding pattern at the fix indefinitely, and the leg is exited only when the pilot takes deliberate action — typically by selecting an exit, unsuspending the flight plan, or activating the next leg — usually in response to an ATC clearance to leave the hold.
Plain English
A holding pattern in the flight plan that the aircraft will keep flying around and around until you tell it to stop. It does not end on its own — you have to end it.
Context Anchor
Seen in RNAV and FMS instrument procedures when a published hold is part of the route and the pilot must choose when to exit it.
Derivation
In ARINC 424 leg coding, each leg type has a two-letter path-terminator code. 'H' indicates a holding pattern and the second letter shows how the hold ends: HM ends Manually, HF ends after one circuit at the Fix, HA ends at an Altitude. The 'M' is what tells you the pilot, not the system, decides when to leave.
Why Pilots Care
It keeps the aircraft inside protected airspace during a hold until a safe exit point is reached.
Intuition Check
Manual termination does not mean the hold ends automatically after one circuit, a timer, or a distance. It means the pilot must take an action in the navigation system to leave the holding pattern.
Example Sentence 1
Cleared out of the hold, the pilot pressed the exit-hold function to terminate the HM leg and let the FMS sequence to the next waypoint.
Example Sentence 2
The pilot manually terminated the HM leg once ATC issued the next heading.