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Two or three decades ago, I would experience quite uncomfortable blocking of the eustachian tubes, which would noisily unblock and become blocked once more as the plane descended.

I haven't experienced that in recent years, in which I have been flying on considerably newer aircraft.

Is this likely to be a change in the cabin environment or my own physiology - that is, have cabin pressures generally increased so that changes during descent are less dramatic, or have I just become older and less susceptible to blocked ears?

Recent airliners such as the 787 and the A350 have much-touted higher cabin pressure levels; has there also been a general increase in standard cabin pressures over the years?

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No doubt older airlines had a lower max differential pressure as @ymb1 pointed out. More likely though is the fact that modern aircraft have automatic pressurization systems that are designed for maximum passenger comfort as the cabini altitude climbs and descends.

Older manual pressurization systems required a pilot to monitor and adjust the pressurization system anytime the aircraft changed altitude or power settings.

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Let's take the Boeing 737 as an example: an airliner that first flew in 1967 and is still being produced, its variants—old to new—indeed show a trend of increasing pressurization capability.

Note that even the 1967 variant had an automatic controller for the cabin pressurization, and the 200Adv and the Classic shared the same max ceiling of FL370.

The better the engines and the aerodynamics are, the higher they'll fly, and the stronger the aircraft will be made to offer better cabin altitude. However stronger is now easier than in the past thanks to the materials engineering advancements.

1/200 (7.5 psi) → 200Adv (7.8 psi) → Classic (8.65 psi) → NG (9.1 psi)

The higher those values, the lower (denser) the cabin altitude is, for a plane flying at the same altitude.

Those values are the limits, each variant will use lower values in the day-to-day operations to reduce the stresses.


Source of the figures: b737.org.uk

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    $\begingroup$ It also may be partly because airliners have switched from manual systems to automatic. One of the jobs of the flight engineer was to change the cabin altitude as the aircraft climbed and descended. If he changed it too quickly some people's ears couldn't adapt quickly enough $\endgroup$ – TomMcW Jun 7 '16 at 23:56
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    $\begingroup$ Higher max diff doesn't automatically mean that the cabin altitude will be lower. As far as I know, the standard setting is still 8000 ft. Reducing the cabin altitude greatly reduces service life of the (conventional) airframe, as also mentioned on the same b737 link. On the other hand, higher diff allows for higher cruise altitude (provided the aircraft can fly it). $\endgroup$ – Zeus Jun 8 '16 at 3:46
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    $\begingroup$ The 737-200 was limited to FL350; the classics to FL 370, and the Next Generation aircraft to FL410. The max differential of a -200 when the aircraft is at FL410 would probably give a cabin above 10,000', so at least some of the increase in max differential is due to the higher ceilings. The 787 and A-380 may well have cabin altitudes that are typically lower than the 8000' of most 737 flights, but among the 737's the higher "diff" doesn't generally translate into lower cabins. $\endgroup$ – Ralph J Jun 8 '16 at 18:36
  • $\begingroup$ @ymb1, ECS are different. Some are programmed to maintain the diff, some (including, incidentally, 737) have a set cabin altitude. Plus, of course, various limiters like max climb/descent cabin rate, matching the pressure by the time of landing, etc. $\endgroup$ – Zeus Jun 9 '16 at 2:00
  • $\begingroup$ @ymb1 At least on Boeing aircraft, you have to "buy" a low cabin altitude option to go above a certain diff on a regular basis. The options literally cuts the life of the airframe in half. If I remember correctly it'll take you from 8000 to 6500 at FL410. It is pretty much a VIP aircraft only option. $\endgroup$ – OSUZorba Jun 9 '16 at 3:36

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