Aerodynamics, flight performance, navigation and atmospheric formulas used in aviation
Quick estimate: true airspeed increases about 2% per 1000 ft of altitude above indicated airspeed.
Ground speed is true airspeed adjusted for the headwind/tailwind component.
Time en route equals distance divided by ground speed.
Total fuel needed is the fuel-burn rate multiplied by flight time.
Vertical speed is the altitude gained per unit time (ft per minute).
On a standard 3° glide path, required descent rate (fpm) is roughly ground speed (kt) times 5.
Resolve wind into headwind and crosswind components relative to runway/track.
Altitude referenced to standard pressure; correct field elevation for the altimeter setting.
Fuel to be loaded: the required ramp/block fuel minus fuel already on board, converted from mass to volume using fuel density.
Latest date a deferred defect must be fixed: the discovery date plus the Minimum Equipment List category interval. The day of discovery is “day zero” and is not counted.
Aerodynamic lift produced by a wing depends on air density, speed squared, area and lift coefficient.
Aerodynamic drag force on the aircraft, analogous to lift with a drag coefficient.
Minimum speed for level flight, set by maximum lift coefficient.
The g-load in a level, coordinated turn depends only on the bank angle.
Accelerated stall speed rises with the square root of the load factor.
Radius of a level coordinated turn from speed and bank angle.
Angular rate of a coordinated turn (radians/s; a standard rate turn is 3°/s).
Crosswind component determines whether landing is within aircraft limits.
Pressure altitude corrected for non-standard temperature; higher DA reduces performance.
Horizontal distance traveled per unit of altitude lost equals the lift-to-drag ratio.
Ratio of true airspeed to the local speed of sound.
Local speed of sound (kt) as a function of absolute air temperature (Kelvin).
Distance flown per unit of fuel; maximizing it gives best fuel economy.
Farthest distance an aircraft can fly and still return with available endurance.
Ratio of inertial to viscous forces; characterises airflow over an airfoil.
Non-dimensional lift, obtained by rearranging the lift equation.
Drag due to lift, decreasing with higher aspect ratio and span efficiency.
Ratio of wingspan squared to wing area; higher AR reduces induced drag.
In steady level flight, thrust must equal drag, which is weight divided by L/D.
Maximum range of a jet aircraft from speed, efficiency, L/D and fuel fraction.
Longest time aloft for a jet, maximized at maximum L/D.
Standard atmosphere temperature decreases about 2°C per 1000 ft up to the tropopause.
Altitude derived from the ratio of sea-level to measured pressure.
Approximate ground-roll distance assuming constant acceleration to lift-off speed.
Climb angle (as a fraction) equals excess thrust divided by weight.
Shortest distance between two points on the Earth for long-range navigation.
Distance traveled forward per unit of height lost.
Ratio of lift to weight, felt as g-force.
Radius of a coordinated banked turn.
Minimum speed to maintain lift.
Ratio of speed to the local speed of sound.
Vertical speed from excess engine power.
Aircraft weight per unit wing area.
Sideways wind component during landing.
Wind component along the runway.
Time an aircraft can stay airborne.
Airspeed corrected for altitude.
Pressure altitude corrected for temperature.