Inadequate cooling capacity from Packs on the ground in high humidity tropical climates. It doesn't matter whether you're a pax cramped aboard a new B777 or a new B744... If the cabin is full and when humidity and ambient temperatures are high, the cabin temperature climbs to uncomfortable high levels.
Contributing to pax discomfort include improper technique by some cockpit crew who fail to select, or belatedly select, "Max Cool" at Top Of Descent into tropical airports with high ambient temperature and humidity. I know that the cockpit will get cool, but the crowded
cabin can quickly get very warm and stuffy.
It's a technical shortcoming that aircraft manufacturers should address seriously, especially for airlines that stuff their cabins full with ever more seats.
