Definition
A bearing arrangement in which two bearings are mounted in line with each other on the same shaft so that they share an axial load between them. Each bearing carries part of the load along the shaft's axis, allowing the assembly to handle thrust forces greater than a single bearing of the same size could support.
Plain English
Two bearings placed one behind the other on a shaft so they work together to carry a pushing or pulling load along the shaft.
Context Anchor
Seen in aircraft maintenance descriptions for rotating parts, gearboxes, engines, and other assemblies where a shaft needs strong, aligned support.
Derivation
Tandem comes from the Latin word for 'at length' or 'at last,' and was later used humorously in English for a carriage drawn by two horses harnessed one behind the other rather than side by side. The aviation usage keeps that picture: two bearings lined up one behind the other, pulling together.
Why Pilots Care
Distributes loads on high-stress rotating parts, extending component life and reducing risk of sudden engine failure.
Intuition Check
Do not read tandem bearings as just any two bearings near each other. The key idea is that they are lined up to support the same rotating part or load together.
Example Sentence 1
The propeller shaft is supported by tandem bearings to handle the thrust produced in flight.
Example Sentence 2
Tandem bearings in the propeller hub allow the shaft to handle both thrust and radial forces without deflection.