# How do I calculate the landing weight in this situation?

Empty weight 538kg
Pilot and passengers are 150kg with full fuel tanks

If we use 2 US gallons for taxi and 10 US gallons for the trip, what will be our landing weight?

• Fuel Capacity
• Total Fuel Quantity: 24.5 US gal. (93.0 liters)
• Usable Fuel: 24.0 US gal. (91.0 liters)
• Unusable Fuel: 0.5 US gal. (2.0 liters)
• Its a bit unclear what you are asking. If 538 KG is your empty weight and 150 KG is your pax weight we would need to know how much fuel the plane holds to get the total weight. What ever the total is you will burn ~32.7 KG's of fuel and can use that for the subtraction. We would need a bit more info to help out.
– Dave
Commented Dec 3, 2018 at 23:53
• Fuel Capacity Total Fuel Quantity: : 24.5 US gal. (93.0 liters) Usable Fuel: : 24.0 US gal. (91.0 liters) Unusable Fuel: : 0.5 US gal. (2.0 liters) Commented Dec 4, 2018 at 0:07
• There isn't enough information to calculate the balance, but the weight can be calculated (from your original title) Commented Dec 4, 2018 at 1:37

$$\mathrm{Empty~Weight} + \mathrm{Crew} + \mathrm{Fuel} = \mathrm{Ramp~Weight}\\ 538\, \mathrm{kg} + 150\, \mathrm{kg} + 93\, \mathrm{L} \cdot \Bigg[\frac{0.72\, \mathrm{kg}}{\mathrm{L}}\Bigg] = 754.96\, \mathrm{kg}$$
During Taxi, you said 2 gallons of fuel will be used: $$\mathrm{Ramp~Weight} - \mathrm{Taxi~Fuel} = \mathrm{Takeoff~Weight}\\ 754.96\, \mathrm{kg} - 2\, \mathrm{gal} \cdot \Bigg[\frac{2.72\, \mathrm{kg}}{\mathrm{gal}}\Bigg] = 749.52\, \mathrm{kg}$$
Then subtract the weight of the fuel that will be used on the trip: $$\mathrm{Takeoff~Weight} - \mathrm{Trip~Fuel} = \mathrm{Landing~Weight}\\ 749.52\, \mathrm{kg} - 10\, \mathrm{gal} \cdot \Bigg[\frac{2.72\, \mathrm{kg}}{\mathrm{gal}}\Bigg]= 722.32\, \mathrm{kg}$$