unha - verb
- unhampered performance
- unhampered performance limit
- unhurried activity
- unidirectional angular acceleration
- unidirectional vibration
- unilateral dichromat
- unilateral lesion
- unilateral myopia
- unimpaired performance
- unintended happening
- unintentional action
- unique trait
- unit flight surgeon
- unit medical officer
- unitary dynamic source trait
- unitary independent variable
- universal language of aviation
- Universities Space Research Association
- unknown attitude
- unknown cause
- unknown origin
- unlearned reflex
- unlearning
- unlearning process
- unmanned spacecraft
- unnecessary fatigue
- unorientation
- unpressurized
- unpressurized portion
- unpressurized suit
- unrecognized spatial disorientation
- unrelated task
- unrelated want
- unreliable behavior
- unrestrained
- unrestricted flying duty
- unsafe action
- unsafe behavior
- unsafe condition
- unsafe feature
