Definition
An instrument cross-check technique in which the pilot's eyes return to the attitude indicator after looking at each of the other flight instruments, so the scan pattern radiates outward from the attitude indicator and back, like spokes from a hub.
Plain English
A way of scanning the cockpit instruments where you always glance back at the attitude indicator between each other instrument you check.
Context Anchor
Used in instrument flying with an electronic flight display, especially when learning a selected radial cross-check.
Derivation
‘Radial’ comes from the Latin radius, meaning ‘ray’ or ‘spoke of a wheel.’ The scan is called radial because the pilot's gaze moves out to one instrument and back to the centre, then out to another and back, just like spokes connecting a wheel's hub to its rim.
Why Pilots Care
It keeps the pilot's attention focused on the most important instrument while still catching deviations in airspeed, altitude, or heading before they become large.
Analogy
Think of the attitude indicator as home base. You step out to check one thing, come back, step out to check another, come back. You never wander far from home.
Intuition Check
Radial does not mean a VOR radial here. Here, it means a scan that moves outward from a central display and returns to it.
Example Sentence 1
The instructor told the student to use a radial scan pattern, returning to the attitude indicator after each glance at the airspeed, altimeter, and heading indicator.
Example Sentence 2
Using a radial scan pattern allowed the pilot to notice a slow altitude drift while maintaining level flight on instruments.