AROTA
Conversions
Converting to and from units has never been easier
NM & KM
Knots & km/h
(NM x 2) - 10% = Kilometers
(km ÷ 2) + 10% = Nautical miles
When using this rule of thumb, we can quickly approximate NM/knots or KM & km/h. 1 NM = 1.85km 1 km = 0.54NM But the rule above is easier to remember. Example: 50NM ≈ (50 x 2) - (50 x 2 x 10%) ≈ 100 - (100 x 0.1) ≈ 100 - 10 ≈ 90 km *The precise conversion is 50NM = 92.6 km, making it a relatively accurate rule. This also works for converting speed, for example, 300km/h ≈ (300 ÷ 2) + (300 ÷ 2 x 0.1) ≈ 165 knots *The precise conversion for 300km/h = 161.987 knots
Meters (m) & feet (ft)
(ft ÷ 3) - 10% = meters
(m x 3) + 10% = feet
When using this rule of thumb, we can quickly approximate between meters (m) and feet (ft). 1 foot = 0.3048 meters 1 m = 3.28 feet But the rule above is easier to remember. Example: 5,000 m ≈ (5,000 x 3) + (5,000 x 3 x 10%) ≈ 15,000 + (15,000 x 0.1) ≈ 15,000 + 1,500 ≈ 16,500 ft *The precise conversion is 5,000 m = 16,404 ft, making it a relatively accurate rule. Example 2: 9,000ft ≈ (9,000 ÷ 3) - (9,000 ÷ 3 x 0.1) ≈ 2,700 m *The precise conversion for 9,000 ft = 2,743 m
Meters per second(m/s) to Feet per min (ft/min)
m/s x 200 = ft/min
ft/min ÷ 200 = m/s
The exact factor to convert between these units is 196.85039370079, but it is much easier to mentally calculate using 200. Example: An aircraft climbing at 500 ft/min is also climbing at 2.5 m/s. (500/200) An aircraft descending at 1.5 m/s is also descending at 300 ft/min. (1.5 x 200)
Degrees Fahrenheit (°F) & Celsius (°C)
([°C × 2] – 10%) + 32 = °F
([°F – 32] + 10%) ÷ 2 = °C
When using this rule of thumb, we can quickly approximate between farenheit (F) and celcius (C). Exact formula: Fahrenheit to Celsius Formula: (°F - 32) / 1.8 = °C Celsius to Fahrenheit Formula: (°C * 1.8) + 32 = °F But the rule above is easier to remember. Example: 20°C = [(20 x 2) - (20 x 2 x 0.1)] +32 = 40 - 4 + 32 = 68°F Example 2: 10°F = [(10 - 32) + (10 - 32)(0.1)] ÷ 2] = (-22 + (-2.2)] ÷ 2 = -12.1°C *The precise conversion leads to -12.2°C
Litres(L) and US gallons (USG)
(Liter ÷ 4) + 5% = US Gal
(US Gal x 4) - 5% = Liter
When using this rule of thumb, we can quickly approximate between liters and US Gallons. There is 3.785411784 Liters in 1 US Gallon But the rule above is easier to remember. Example: 1200 L ≈ (1200/4) + (1200/4 x 0.05) ≈ 300 + 15 ≈ 315 US Gal *The precise conversion is 1200L = 317 US Gal, making it a relatively accurate rule. 150 US Gal ≈ (150 x 4) - (150 x 4 x 0.05) ≈ 600 - 30 ≈ 570 L *The precise conversion for 150 US Gal = 567.8117 L
Kilograms (kg) & pounds (lb)
(kg x 2) + 10% = pounds
(lb ÷ 2) - 10% = kilograms
When using this rule of thumb, we can quickly approximate between kilograms (kg) and pounds (lb). 1lb = 453.59237g, but the rule above is easier to remember. Example: 500 kg ≈ (500 x 2) + (500 x 2 x 0.1) ≈ 1000 + 100 ≈ 1,100 lb *The precise conversion is 500 kg = 1,102.31 lb, making it a relatively accurate rule. Example 2: 6,000lb ≈ (6,000 ÷ 2) - (6,000 ÷ 2 x 0.1) ≈ 2,700 kg *The precise conversion would be 6,000lb = 2,721.55 kg *Note, not all liquids have the same specific gravity, therefore you need to consult your own aircraft manual or operating procedures first and foremost!