Combi aircraft are aircraft that can be used to carry both passengers and/or cargo. While most aircraft are designed specifically for carrying either passengers or cargo, combi aircraft offer flexibility for use as an airliner or as a cargo freighter.
Combi Aircraft Features
The main advantage of combi aircraft is the dual-purpose capability of carrying both passengers and cargo, allowing airliners to maximize the space used on their flights. Some examples of features that enable combi operation are:
- An oversized cargo door to enable easy cargo movement in and out of the aircraft
- Tracks on cabin seats allowing them to be quickly removed or added
- A wall to split the main cabin between passenger and cargo zones. The passenger zone of the cabin should also be pressurized to prevent fumes from the cargo zone from leaking.
Notable Combi Aircraft Models
Cargo has been a core component of the aviation industry since its beginnings. Early airlines like Northwest Orient utilized Douglas DC-7 planes within their fleet to transport passengers and cargo simultaneously.
Combi aircraft usage grew into the 1960s and 70s, with a notable proponent being Boeing. The Boeing 747 family of aircraft have spawned many combi aircraft as Boeing were one of the main proponents of combi flight within the industry. The 747-200M was the first jumbo combi aircraft by Boeing, and the -300M and -400M followed afterwards. By 1977, 40 Boeing 747s were modified for combi capability. The 727 and 737 family also had combi aircraft models.
Other notable combi aircraft throughout history include the ATR 42-300, Convair CV-240, and the Lockheed L-188 Electra.
For most use cases, combi aircraft have fallen out of favor in modern aviation. Due to their dual responsibility, combi aircraft have increased loading times and are forced to keep to passenger schedules while still maintaining cargo operations, resulting in a fundamental inefficiency in operations. As demand for both cargo and passenger flights increased, dedicated air cargo services instead rose in popularity.
However, certain airlines still use combi aircraft for their unique flexibility. Companies like KLM, Alaska Airlines, and Canadian North, due to a combination of climate, area, and demand, successfully utilize combi aircraft to make up for the lack of demand on certain routes.