The cargo bay cannot have a different air pressure than the passenger part:
-) this would need a stronger floor
-) strain the fuselage differently between upper and lower
-) exclude animals from being transported in the bay
The air pressure in an airliner should not exceed an analog height of about 2500m . Thus you could not go onto a mediocre mountain with such lens (unless it got a slight gas leakage, enough for a slow climb by foot).
-) this would need a stronger floor
-) strain the fuselage differently between upper and lower
-) exclude animals from being transported in the bay
The air pressure in an airliner should not exceed an analog height of about 2500m . Thus you could not go onto a mediocre mountain with such lens (unless it got a slight gas leakage, enough for a slow climb by foot).