Pressure Changes — Ear & Sinus Blocks

The atmosphere as a pressure environment

Every climb is a decompression; every descent is a compression. The body's air-containing cavities — middle ear, sinuses, GI tract, lungs (always) — adjust their gas volume to match the surrounding pressure. Most of the time the adjustment is passive and unnoticed. When passages narrow or close (because of congestion, infection, or anatomy), the adjustment fails and the cavity ends up at the wrong pressure, with consequences ranging from mild discomfort to incapacitating pain to actual eardrum rupture.

The atmospheric scaling: pressure roughly halves every 18,000 ft. Going from sea level (29.92 inHg) to 8,000 ft (~22.2 inHg), pressure drops about 25%; trapped gas volumes expand correspondingly. For a piston helicopter cruising at 6,000–10,000 ft, this is small enough to manage. For pressurized turbine cabins climbing through 18,000 ft cabin altitude during depressurization training, or for HEMS aircraft with a quick descent to a low-elevation LZ, the changes are larger and the failure modes more painful.

The middle ear and the eustachian tube

The middle ear is a sealed air-filled cavity behind the eardrum, containing the small bones (malleus, incus, stapes) that conduct sound vibrations. Its pressure must match the outside (atmospheric) pressure for the eardrum to function and for the cavity to be comfortable.

Pressure equalization happens through the eustachian tube — a small soft-walled tube connecting the middle ear to the back of the throat (nasopharynx). The tube is normally closed, opening briefly during chewing, swallowing, yawning, or by deliberate pressure (Valsalva, Toynbee).

The asymmetry that matters in flight: the eustachian tube is a one-way valve in practice.

• On climb (decreasing outside pressure): middle-ear air is now at higher pressure than outside. The expanding air pushes the eustachian tube open from the middle-ear side. Equalization happens passively — most pilots feel a slight click or fullness on climb, but no action is required.
• On descent (increasing outside pressure): outside air is now at higher pressure than the middle ear. The pressure differential closes the eustachian tube further (rather than opening it). The pilot must actively open the tube — Valsalva maneuver, swallowing, yawning, or chewing. Without active equalization, the eardrum bows inward, generating pain that escalates from "pressure" to "sharp pain" to "incapacitating" with continued descent.

Equalization techniques

Listed by aggressiveness — start with the gentlest that works:

• Swallowing. The simplest. Each swallow opens the eustachian tube briefly. Effective during slow descents.
• Yawning. A bigger jaw motion than swallowing, opens the tubes more reliably. Slightly less subtle but very effective.
• Chewing. Gum or food. The continuous jaw motion repeatedly opens the tubes. Useful for sustained descents.
• Toynbee maneuver. Pinch the nose closed, then swallow. The tongue creates a slight negative pressure in the nasopharynx that helps open the tube.
• Valsalva maneuver. Pinch the nose closed, close the mouth, exhale gently against the closed airway. Forces air into the eustachian tube. Effective but requires care:
  • Use gentle pressure, not forced. Over-aggressive Valsalva can rupture an eardrum if the tube is severely blocked.
  • Don't Valsalva if you're already congested — pressure can push infected mucus from the throat into the middle ear, causing otitis media.
  • Stop and try a different technique if Valsalva produces sharp pain.
• Frenzel maneuver. Used by SCUBA divers and some pilots — close the nose, close the throat, push the tongue up and back. Bypasses some of Valsalva's risks. Requires practice.

If multiple techniques fail and pain is escalating during descent: level off and climb back to a comfortable altitude, then descend more slowly with continuous equalization attempts. ATC will accept this request — "I'm having ear-block trouble, request slower descent" is a legitimate ATC negotiation.

Sinus blocks

The paranasal sinuses (frontal, maxillary, ethmoid, sphenoid) are air-filled cavities in the skull that connect to the nasal passages through small openings. When those openings are inflamed or congested, sinuses can't equalize with ambient pressure during altitude changes.

• On climb: Trapped sinus air expands; if the opening is partially blocked the trapped air may force its way out, sometimes painfully.
• On descent: Ambient pressure compresses, trapped sinus air can't accept more from outside (because the opening is blocked), creating a vacuum that produces pain.

Sinus block pain is typically more diffuse and "throbbing" than ear block, and often accompanied by headache or pressure behind the eyes. Frontal-sinus blocks (forehead pain) are most common; maxillary-sinus blocks (cheek/upper-jaw pain) can mimic toothache.

Recovery: there's no Valsalva equivalent for sinuses. The mitigation is altitude management — climb back, descend slowly, hope the openings clear with time. The prevention is don't fly with sinus congestion.

Don't fly with a head cold (or right after)

Upper respiratory infections, allergies, and even mild congestion are the typical cause of ear and sinus blocks. The aeromedical advice is consistent: don't fly when you have a cold or recent congestion. The IMSAFE "I" letter (Illness) covers this directly.

Specific cautions:

• Decongestants temporarily mask the problem. Pseudoephedrine and phenylephrine open the eustachian tube and sinus passages but are FAA-relevant medications:
  • Pseudoephedrine causes elevated heart rate, jitteriness, and possible arrhythmias — disqualifying under § 91.17 if symptoms are present.
  • Effects last several hours; if congestion returns mid-flight at altitude (rebound congestion), the eustachian tube can suddenly close on descent, producing a worse ear block than the original.
  • Phenylephrine is similar but generally less potent. Same concerns apply.
• Sedating antihistamines (diphenhydramine, doxylamine) are flat-out disqualifying — see Alcohol, Drugs & Fatigue. Loratadine, fexofenadine, cetirizine are usually FAA-acceptable but ask your AME.
• Recent cold (1–2 weeks past) — eustachian tube and sinus openings can remain inflamed and prone to blockage even after symptoms resolve. The general guidance is to fly only when fully recovered, not just symptomatic-recovered.
• Recent ear infection — wait until cleared by your AME or a treating physician. Pressure changes during recovery can rupture the eardrum or push infection into the middle ear.

The professional pilot's answer: when in doubt, ground. The cost of a missed flight is small; the cost of an in-flight ear block at FL080 with no easy descent is much larger.

Other gas-related issues

• Trapped GI gas expands on climb. Most pilots experience occasional belching or flatus on climb to altitude — minor and self-resolving. Severe gas pain at altitude is uncommon but possible; level off and consume small amounts of water if symptoms develop.
• Aerodontalgia — tooth pain at altitude, caused by trapped gas in a poorly-filled tooth or under a crown. If you've had recent dental work, ask your dentist about altitude exposure before flying high.
• Decompression sickness (DCS, "the bends") — relevant for pilots who fly after SCUBA diving. Nitrogen dissolved in body tissues during the dive can come out of solution at altitude, forming bubbles that produce joint pain, neurological symptoms, or worse. FAA / DAN guidance:
  • Wait at least 12 hours after a single no-decompression dive before flying.
  • Wait at least 24 hours after multiple dives or any dive requiring decompression stops.
  • For higher-altitude flights (turbine cabin altitudes above 8,000 ft), the wait should be longer.
• Hyperbaric chamber exposure (medical or training) follows similar guidance — ask the supervising physician for clearance before flying.