How much freight can a Boeing 737-800 NG carry if the majority of seats are removed?

Question

In the context of the COVID-19 crisis, I read reports of underused Boeing 737-800 NG aircraft being converted (by technicians in airports, not by factories) to cargo planes for medical equipment. How much freight (in tons) can such an airplane transport? How much weight can the place below each seat withstand? The flight distance would be about 5000 km. It appears that one such airliner carried only 9 tons also, as can be seen in the images, it was loaded close to its maximum capacity. I guess the freight (200000 masks FFP2) was light.

Boeing 737-800 NG

VIDEO with such a Boeing 737-800 NG full of medical equipment

Press release:

9 (nine) tons of medical equipment brought from China by a Tarom aircraft - Bucharest, April 3, 2020. In the middle of the crisis generated by the coronavirus pandemic, a Boeing 737-800 NG aircraft has been reconfigured to import from China 9 tons of medical materials. The plane took off from Bucharest Otopeni airport on April 2 and through Almaty (Kazakhstan) reached Shenzhen (China) and then returned on the evening of April 3. Two Boeing 737-800 NG passenger planes have been reconfigured.

Answer 1

At 160 seats, a -800 carries 16 tons of people in the cabin, plus freight/luggage in the belly, plus fuel. At 180 seats, that becomes 18 tons of pax. If you assume one 50# suitcase per person, add a quarter of that again, so 20 to 22.5 tons. Much more than that you're probably starting to run up against the Max Zero Fuel Weight limit, although I don't have the right charts in front of me to give an exact answer there.

If the flight is long enough, max takeoff weight becomes an issue, as your fuel load starts to cut into your lift. Obviously lots of factors go into how much fuel a flight requires; "today's" winds & temperature & destination weather (alternate required? How far away?) will change how much weight today's flight can take.

Ballparking it with back-of-the-envelope math, anything up to about 3-4 hours, you can probably get those weights I mentioned above (i.e. 22 tons or so). Much more than that, I'd expect max takeoff weight to limit you, so more distance = less payload.

If the legs were 5000km between refueling stops, then you're well into the limit being max takeoff weight, rather than what the jet could carry on a short-haul.

Depending on the nature of the cargo, the limits on floor loading in the cabin + the cargo compartments may be limiting, or volume may be limiting. If you're hauling pingpong balls, it's all about volume. If hauling gold, floor weight capacity & total weight will be more limiting. If it's all rucksacks, then you can probably leave the seats in & load around them, and only total weight will play.

Disclaimer, doing this with no references in front of me, and I may have a number off in there. When there is a specific need to haul "this" from A to B, the guys with the charts & load plans come up with a far more specific answer. The above is simply a rough ballpark.

Answer 2

A Boeing 737-800 NG with all seats removed can not carry more than 24 000 kg of payload and the maximum volume transported can not surpass 184 m3, no matter what you do, as long as, according to the article B737-800BDSF Passenger to Cargo Conversion, "the 737-800BDSF [a factory modified 737-800 NG] is the second B737 New Generation converted freighter offered by IAI's Aviation Group" and it has the following characteristics:

Weights and Volumes:

MTW - Up to 174,700 lb

MTOW - Up to 174,200 lb

MZFW - Up to 138,300 lb

MLW - Up to 146,300 lb

Payload - 53,000 lb = 24000 kg

Fuel Capacity - 6,875 USG

Main Deck Cargo Volume - 4,999 ft3 = 141 m3

Lower Decks Bulk Volume - 1,543 ft3 = 43 m3

Source of images