Definition
A switch action in which a control is moved to the OFF position only briefly, then released or returned, rather than being left in OFF. In aircraft electrical systems, this phrasing typically describes a spring-loaded switch that the pilot holds in OFF for a short moment to perform a specific check or reset, after which the switch returns to its normal position on its own.
Plain English
The switch is flicked to OFF for just a second or two, not left there. Often the switch is spring-loaded, so it springs back as soon as you let go.
Context Anchor
Used during piston-engine run-up or idle checks when checking that the ignition switch shuts the engine ignition off properly.
Derivation
Momentarily comes from the Latin momentum, meaning a brief movement or short space of time. In this phrase it keeps that everyday sense — for just a moment — and tells the pilot the switch should not be held in OFF or left there.
Why Pilots Care
Confirms switch operation and proper grounding without shutting down a running engine or critical system.
Grounding Statement
This is only a quick check, not a normal engine shutdown.
Intuition Check
Do not read this as leaving the switch OFF for a while. In this context, momentarily means OFF only long enough to verify the response, then back ON immediately.
Example Sentence 1
During the runup, the ignition switch is momentarily placed in the OFF position to confirm both magnetos are properly grounded.
Example Sentence 2
The starting procedure directs that the battery switch be momentarily placed in the off position to verify warning light function.