Why it happens: During takeoff and landing, rapid changes in cabin pressure create a difference between the pressure in your middle ear and the outside environment. Normally, the Eustachian tube equalizes this by opening briefly. If it’s blocked (e.g., by congestion, allergies, or a cold), the pressure imbalance persists, causing a “popped” or “blocked” sensation, muffled hearing, or even pain.
| Phase conductor cross-section (mm²) | Minimum earth conductor size (mm²) | |--------------------------------------|-------------------------------------| | ≤ 16 mm² | Same as phase conductor | | 25 – 35 mm² | 16 mm² | | > 35 mm² | Half of phase conductor size (rounded up to next standard size) | [ S = \frac\sqrtI^2 \times tk ] ears popping after flightearth cable size calculation