Definition
The breakdown of a material into simpler substances, usually through chemical reaction, heat, moisture, or biological action. In aircraft maintenance, decomposition refers to the deterioration of materials such as composites, adhesives, sealants, fuels, or fabrics over time, resulting in a loss of their original physical or chemical properties.
Plain English
A material breaking down and losing its strength, shape, or chemical makeup. The original substance is no longer what it was — it has come apart at a molecular or structural level.
Context Anchor
Seen in aircraft maintenance when discussing damage to materials such as sealants, fabrics, plastics, composites, wood, rubber, or other parts exposed to heat, moisture, chemicals, or age.
Derivation
From Latin de- (apart, down) + componere (to put together). Literally 'to come apart.' The word originally meant the reversal of putting something together — a useful image for what happens when a material loses its structure.
Why Pilots Care
Decomposition of aircraft materials can quietly reduce strength, seal integrity, or fuel quality long before visible signs appear. Recognizing it during inspection prevents in-service failures.
Intuition Check
Do not think of decomposition only as something that happens to plants or food. In aircraft maintenance, it means any material is chemically or physically breaking down from its original condition.
Example Sentence 1
The technician suspected decomposition of the bonding adhesive after finding soft, discolored areas along the panel edge.
Example Sentence 2
Fabric decomposition around the fuselage allowed moisture to reach the internal structure.