I am very interested in the 737 combi models and want to learn more about how they worked in practice. For the 737 Combi, How did changing the proportions of the passenger vs cargo areas work?

  • I have read that regulations require passenger areas to be maintained at higher pressures than cargo areas in order to prevent potential fumes from reaching the passengers- is that true? If so, how does that work in terms of the air pack design and other aspects of the cabin air design?
  • Could operators change back and forth the proportion of floorspace that they dedicated to cargo vs passengers, or was it semi-permanently fixed? If it could be changed in normal operations, about how long did it take or how many man hours?
  • Could the bulkhead between the passenger and cargo areas be located at any point inside the aircraft ("infinitely variable bulkhead location" you might say) or were there a certain number of fixed points that the bulkhead could be positioned?
  • For 737 combis operated in a 100% passenger configuration, what did the cabin look like next to the door? Was the cargo door basically fully finished as though it was any other part of the cabin, or was it more industrial looking/louder/colder?

2 Answers 2


Boeing 737QC Interior without seats

The Boeing 737QC (Quick Change) is a Boeing 737-200 which featured a 134 in × 87 in (340 cm × 221 cm) freight door just behind the cockpit. The floor was strengthened and allowed for palletized seating for faster configuration changes between cargo and passenger flights. A switch using a system designed by Falcon Aviation in Sweden allowed the seats to be removed in 20 minutes. Each seat row would roll forward to the cargo door, then slide out into a container for storage. The container would be rolled away and cargo loaded into the space where the seats used to occupy.

The video below shows how the conversion system created by Falcon worked.

Good luck creating a toy hauler.

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    $\begingroup$ Great video! Very cool to see how the floor finish is integrated as a single unit with both sets of seats and the aisle. This still only addressed the example of switching from 100% pax to 100% cargo so I still am left wondering about the combined configuration and how the bulkhead is mounted and any configurations that have to be done to address air pressure or whatever other concerns of carrying cargo in the same cabin as passengers. "Good luck creating a toy hauler" exactly, this thing is basically an airliner sized Pilatus, which is so cool. The -200 was even available with a gravel kit. $\endgroup$
    – Charles847
    Feb 27, 2019 at 5:10

For the -200QC model, there appears to be variable cargo and passenger volumes: https://www.flickr.com/photos/57440551@N03/34619249303

The "Combi" is fixed at half cargo, half passengers, and it appears to not be an original type, but a conversion after delivery.

Regarding the last point, the Cargo Door appears to have the same windows and has overhead bins.

so there appears to be minimal distinction between the cargo door and the rest of the cabin.

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    $\begingroup$ I definitely have seen pictures of combi models where the pax windows stop midway through the fuselage, stopping even before the cargo door, so I know that there must be some options for how you configured these. I also know that historically, some airlines purchased new Combis with cargo doors fully intending to use them for 100% passenger service, and only equipping the cargo doors in anticipation of resale market value. I wonder if those planes even retained the ability to open their cargo door. Still hoping to learn more about how these QCs work. $\endgroup$
    – Charles847
    Feb 26, 2019 at 18:50
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    $\begingroup$ Alaska airlines had a couple of the true combi type (half windows) but i think they retired them 20 years ago. They actually do use the cargo space for cargo on the smaller northern routes. The also had a few with a gravel runway option, to keep rocks out of the engines. This work is actually what the 737 was originally intended for, and why it has short landing gear-> loading cargo and baggage at remote airports without fancy high lift machines. $\endgroup$
    – Max Power
    Mar 29, 2019 at 5:02

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