# 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 Dec 3 '18 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) – Enki Sumerian Dec 4 '18 at 0:07
• There isn't enough information to calculate the balance, but the weight can be calculated (from your original title) – Ron Beyer Dec 4 '18 at 1:37

## 1 Answer

First calculate your weight on the ramp:

$$\mathrm{Empty~Weight} + \mathrm{Crew} + \mathrm{Fuel} = \mathrm{Ramp~Weight}\\ 538\, \mathrm{kg} + 150\, \mathrm{kg} + 93\, \mathrm{L} \cdot \Bigg[\frac{0.72\, \mathrm{kg}}{\mathrm{L}}\Bigg] = 754.96\, \mathrm{kg}$$

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: $$\mathrm{Takeoff~Weight} - \mathrm{Trip~Fuel} = \mathrm{Landing~Weight}\\ 749.52\, \mathrm{kg} - 10\, \mathrm{gal} \cdot \Bigg[\frac{2.72\, \mathrm{kg}}{\mathrm{gal}}\Bigg]= 722.32\, \mathrm{kg}$$