Preflight planning is a very important element of any flight and especially so when embarking on a cross country flight. There are a number of items to be done in preparation for a VFR cross country in such a way that nothing is overlooked and the intended flight is done as safely as possible.
The pilot will (must) perform a number of calculations during preflight planning and those we use on the site are listed below for convenient access. Sometimes the use of a special aviation calculator (E6B models or electronic Jeppesen) is required, other times it can be done without the use of such devices. Have a look at our E6B Tools too!
As a reference, we compiled a list of formulas we used throughout the site on the panels below:
Flight planning
Compass Heading: TC +/-WCA = TH +/-VAR = MH +/-DEV = CH
Estimated Time Enroute (ETE): Time = Distance / Speed
Weight Shift problems: Distance Weight Shifted × Weight Shifted = Total Weight × Delta C of G
Track Error (1 in 60 rule): TE = (60 / Distance Flown ) × Distance to Track
Closing Angle (1 in 60 rule): CA = (60 / Distance to Go) × Distance to Track
Aerodynamics
Load Factor: G = 1 / cos (Bank Angle) or G = L / W
Higher Stall Speed in a turn: Vsacc = Vs × √ Load Factor
Increased Stall Speed at higher weight: Vs new = Vs Old Weight × √(New Weight / Old Weight)
Lift Formula: L = ½ ρ v2 × S × CL or simplified: Lift = IAS × CL
Dynamic Pressure (IAS): IAS = ½ ρ v2
True Airspeed (TAS): TAS = IAS × √ (ρ0 / ρ)
Propeller Efficiency: Thrust × TAS / Brake Horse Power
Propeller Tip Speed (π is PI, 3.1415...): vTIP = π d N
Aircraft performance
Pressure Lapse Rate: PLR = 96 × T (Kelvin) / QNH (hPa)
Pressure Altitude: Pressure Altitude = Altitude + (1013 - QNH) × 27
Density Altitude: Density Altitude = Pressure Altitude + (OAT - ISATpa) × 120
Specific Air Range (SAR): SAR = (TAS / Power) × (1 / SFC)
Specific Ground Range (SGR): GS / Fuel Flow or GS / Power
Best Specific Fuel Consumption (SFC): SFC = TAS / Power
Physics
Gravitational acceleration: 9.80665 m/s2
Kinetic Energy (Joule): Ek = ½ × m × v2
Potential Energy (Joule): Ep = m × g × h
Elastic Energy (Joule): Ee = ½ × k × x2
Force (Newton): F = m × a
Work (Nm or Joule): W = Force × Distance
Power or the Rate of doing Work (Watt or J/s): Power = Work / Time
Speed of Sound: Vsound = 331,3 × √ (1 + T / 273,15)
Ideal Gas Law: P × V = n × R × T
Heat Capacity (J ⋅ kg-1 ⋅ K-1): c = Q / (m × ΔT)
Thermal Conductivity (W ⋅ m-1): q = -λ ΔT / Δx
Engines
Engine Power (π is pi, 3.141529...): BHP = ((2 π × RPM) / 60) × Torque
Engine Efficiency: Brake Thermal Efficiency = Brake Power / Fuel Consumption
Engine SFC: Brake Specific Fuel Consumption = Fuel Flow / Brake Power
Engine Thrust: Thrust (Drag) = Horsepower × Propeller Efficiency
Power Speed: Speed Increase = Power Increase1/3
Electronics
Luminous Intensity: lm = cd × sr in Lumens (lm)
Candela (all directions): cd = lumens / 4 π
Luminous Flux (lux): lx = lm / m2
Ohms Law: U = I × R in V
Electrical Power: P = U × I in W
Electrical Energy: E = P × t in Wh
VHF Communications Range: Range = 1,33 × (√H-aircraft + √H-gs) in NM
Written by EAI.
