Surely your winding me up now !
What do they teach pilots these days about the airplanes they are flying ? Please tell me your not a Captain !!
The two pressure relief doors aft of the left hand wing root fairing are POSITIVE pressure relief doors as opposed to the NEGATIVE relief doors at the front.
Positive pressure relief valves prevent differential pressure from exceeding stuctural limits in the event of a pressurisation system malfunction. The valves have a primary metering section limiting positive pressure to 8.95 psi diff and a secondary metering section as a back-up which operates at 9.42 psi diff.
These valves should be inspected each preflight and if opened a flag is visible.
(not uncommon so keep your eyes open when doing your walk-around )
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Fools rush in where Angels fear to tread