Definition
Pain, pressure, or temporary hearing impairment caused when air trapped inside the middle ear or the sinuses cannot equalize with changing cabin pressure during climb or descent. As outside pressure drops in a climb, trapped air expands and usually vents out easily; as pressure rises in a descent, outside air must flow back in through the Eustachian tube (for the middle ear) and the small sinus openings. If those passages are swollen or blocked — typically by a cold, allergies, or sinus congestion — the pressure cannot equalize, producing discomfort, sharp pain, possible eardrum injury, vertigo, or temporary hearing loss.
Plain English
When you climb or descend, the air inside your ears and sinuses needs to move in and out to match the changing pressure. If you have a cold or stuffy sinuses, those passages get blocked and the trapped air can't equalize, which causes pain, pressure, and sometimes hearing trouble — especially on the way down.
Context Anchor
Encountered in pilot health, preflight fitness, and altitude-change discussions, especially when deciding whether to fly with a cold, allergy symptoms, or nasal congestion.
Derivation
Ear comes from Old English words for the hearing organ. Sinus comes from Latin, meaning a hollow or pocket. That helps here because the sinuses are hollow air spaces, and those air spaces must adjust as outside air pressure changes.
Why Pilots Care
Can produce sharp pain, vertigo, or distraction that compromises aircraft control and decision-making.
Analogy
Think of a sealed water bottle taken up a mountain and back: it puffs out on the way up and crumples on the way down. Your ears and sinuses do the same thing — but only stay comfortable if the small passages stay open so air can move freely.
Grounding Statement
On descent, outside pressure increases, and a blocked ear or sinus may not let pressure equalize, causing sharp pain or a full, plugged feeling.
Intuition Check
Do not treat this as only a minor comfort issue. In aviation, middle ear and sinus problems can affect pressure, balance, hearing, and safe decision-making.
Example Sentence 1
The instructor cancelled the lesson when the student mentioned a head cold, explaining that middle ear and sinus problems during descent could cause real pain and even injury.
Example Sentence 2
During the training flight the student cleared his ears frequently to avoid middle ear and sinus problems as altitude changed.