If asked in one word, it’s yes. Most commercial cargo planes predominantly use pressurised fleets. The majority of cargo that is shipped requires temperature and pressure controls. The temperature of the cargo is controlled via the pressurization system. However, it depends on the aircraft and the requirements of the cargo (living animals, computer equipment, packaged food, biomedical supplies, perishable goods, etc.) that demand a pressurised cabin. Almost all cargo comes in wrapping, packaging, containers, bottles, etc. and without air freight pressurization control, the cargo will likely get damaged.
Apart from the majority, freights are also shipped to smaller stations through smaller planes that do not fly above 10,000 feet. Hence, not all cargo will be found shipped in pressurised planes. Commercial aeroplanes, both freight and passenger do not fly at a particular altitude without the support of pressurization. For commercial aircraft, pressurization provides shipping comfort, temperature control, and structural support of the consignments. Aircraft are designed to take off and land at internal air pressurization that is greater than outside atmospheric pressure to retain structural support.
Let's first understand the types of air cargo planes.
There are two types of air cargo planes, one carrying general goods and the other carrying special goods. General goods include high-value goods like jewellery and medicine. Special cargo planes have goods like temperature-controlled goods. Shipping such goods is an essential and crucial task, and each shipment has different requirements.
Also, one big significant difference between commercial cargo planes and cargo planes is that commercial planes carry either passengers or freight and charge a fee. In contrast, a cargo plane is completely dedicated to moving shipments locally or globally.
Why do cargo planes use cabin pressurization?
Commercial cargo planes perform their best at high altitudes and this enables the fleets to enhance fuel consumption efficiency and avoid potential turbulence factors. However, for humans, the situation is exactly the opposite. The higher people shift to, the less oxygen there is available for them to breathe in. This happens because air density decreases with altitude, which contradicts human anatomy. Also, one will freeze rather quickly at such an altitude, as the ambient temperature is around -50 degrees Celsius. All the liquid in the packaged cargo will also freeze.
Moreover, at any height greater than 10,000 ft., humans and animals that are not acclimatized will become hypoxic, which is not receiving sufficient oxygen for breathing from the ambient air. There are tables, like the Time of Useful Consciousness (TUC) which varies at various altitudes. Temperature-sensitive cargo may get damaged by both the pressurization alteration and the temperature fluctuations.
Cargo planes pump pressurized air into their fleets and the air that goes into an aircraft's cabin, via this process, is called conditioned air. Once the cabin attains the ideal pressure level, the aircraft will restrict the cabin air exhaust to control the cabin pressure and maintain it at a constant level throughout the flight. In a nutshell, cabin pressurization is a process where conditioned air is pumped into and then, out of the aircraft’s cabin. The inside air of the cabin needs to be refreshed nonstop to enhance the entire cargo flight to become more hassle-free.