Definition
Electromagnetic radiation with wavelengths longer than visible red light but shorter than microwaves. It is emitted by all objects above absolute zero and is felt as heat. In aviation maintenance, it is used in non-destructive inspection methods such as thermography to detect heat patterns that reveal hidden defects, moisture intrusion, or disbonds in composite structures.
Plain English
Invisible heat energy given off by warm objects. Special cameras can see it, which lets technicians spot problems inside parts that look fine on the outside.
Context Anchor
Seen in aircraft maintenance discussions involving heat lamps, temperature checks, thermal inspection, fire detection, and equipment that senses heat without touching the part.
Derivation
From Latin infra (below) and red. The name reflects its position in the spectrum -- just below red light in frequency, sitting beyond what the human eye can see.
Why Pilots Care
Infrared inspection can find water trapped inside honeycomb composite panels, delaminations, and overheating electrical connections that visual inspection would miss. For maintainers, it is a key tool for catching hidden damage before it becomes a structural or electrical failure.
Analogy
A campfire gives off heat you can feel even before you touch anything hot. That warming energy reaching your skin is infrared radiation.
Grounding Statement
Hold your hand near a stove that has just been turned off -- you can still feel warmth even though it is no longer glowing. That warmth reaching your hand is infrared radiation.
Intuition Check
Do not read “radiation” here as radioactive material. In this term, radiation means energy traveling outward, and infrared means the invisible heat-related part of light.
Example Sentence 1
The technician used an infrared camera to scan the composite panel for trapped moisture before releasing the aircraft.
Example Sentence 2
Infrared radiation from the engine helped confirm proper cooling during the ground run.