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AROTA
Equations
Equations, formulas, and other rule of thumbs
Formula | Equation | Notes |
|---|---|---|
Mach number | TAS(True airspeed)/LSS(Local speed of sound) | |
Local speed of sound | Speed of sound (kts)= 38,94 * √T (Kelvin) | |
Lift | Lift = ½ρv²SCᴸ | Cᴸ= Coefficient of lift |
Pressure altitude (PA) | Elevation + (1013 - QNH) (27) or Elevation + 1000 x (29.92 - altimeter setting) | QNH = Forecasted or reported pressure value |
Density altitude (DA) | Pressure altitude + (OAT - ISA deviation) (120) | OAT = Outside air temperature & ISA = International standard atmosphere |
Crosswind | Wind speed x sin wind angle | |
Headwind | Wind speed x cos wind angle | |
Rate one turn | 3°/second | 180° in one minute |
G-force | 1/cos (bank angle) | |
Magnetic bearing | Magnetic heading + Relative bearing = Magnetic bearing | |
Rotation speed VR | VS x 1.15 | VS = Stall speed |
Manouvre stall speed | VS x √n or VS x √1/cosα | VS = Stall speed |
Moment | Weight x arm | |
C.G in % MAC | CG distance aft of LEMAC/MAC | LEMAC: Leading edge mean aerodynamic chord |
Center of gravity | Total moment/Total weight | |
Tire hydroplaning speed | 9 √ tire pressure(psi) | |
Radio range formula | R = 1.25√HT + √HR | HT = Height of transmitter, HR = Height of receiver |
Equal time point (distance) | ETP = (Total distance x inbound groundspeed)/(outbound groundspeed x inbound groundspeed) | |
Equal time point (time) | ETP distance/outbound groundpseed | |
Point of no return (distance) | Total endurance x (Outbound groundspeed x Return groundspeed)/(Outbound groundspeed/Return groundspeed) | |
Point of no return (time) | PNR distance / outbound groundspeed | |
Point of safe return (distance) | Endurance minus reserve x (Outbound groundspeed x Return groundspeed)/(Outbound groundspeed/Return groundspeed) | |
Point of safe return (time) | PSR distance / outbound groundspeed |
Radio navigation instruments, their frequencies, and range
Other rule of thumbs and useful info
Emergency frequencies | VHF 121.5, UHF 243, ELT 406 |
|---|---|
Squawk code for communications failure | 7600 |
Squawk code for emergencies | 7700 |
Squawk code for hijack | 7500 |
Are winds in relation to magnetic or true north? | Both. Forecasted winds are true, reported winds are magnetic |
Windsock | Each segment represent 3kts of wind |
Over the threshold | At the threshold, 1/2 LOC dot = 1/2 runway width |
Aircraft weight | 10% of aircraft weight change will result in 20% change in take-off distance |
Abort take-off | If 70% of takeoff speed is not acheived within 50% of runway |
Takeoff distance for general aviation | You need to reach at least 70% of take-off speed by 50% of runway distance |
For max TAS and range | Load airplane as close to the aft CG limit as allowable |
VOR range (NM) | 1.23 x √Altitude in feet |
A tailwind of 10% of your approach speed | increase landing distance by 20% |
A headwind of 10% of your approach speed | decreases landing distance by 20% |
A 10% change in airspeed | causes 20% increase/decrease in stopping distance |
1000ft in field elevation | changes landing distance by 4% |
A narrow runway… | seems longer on approach |
A wider runway… | seems shorter on approach |
A narrow and uplsoping runway | creates an illusion that the aircraft seems higher on approach |
A wide and downsloping runway | creates an illusion that the aircraft seems lower on approach |
A wet runway | Increases landing distance by 50% |
Land on the 1st 1/3 of runway | Or go around |
Loss of 50% of thrust in a twin engine | Approx 80% loss of ROC |
10 - 25 degrees add more lift than drag | 25 - 40 degrees add more drag than lift |
Having a forward CG… | aircraft more stable and stall at higher speed |
Having an aft CG… | aircraft less stable and stall at a lower airspeed |
Structural icing occurs usually in the range | 0 - 10 degrees |
Mountain flying | Actual horizon is base of mountain |
Mountain flying | Stay on the updraft side of the canyon |
Mountain flying | Approach mountain ridges at 45 degrees |
Approximate AOA before stall | 18 degrees (For most airfoils) |
Glide ratio | A glide ratio of 17:1 means that the aircraft will travel 17000 ft distance for each 1000 ft altitude loss |
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