Field elevation
Where the ground is
The physical launch-site elevation above mean sea level. It stays fixed when the weather changes.
PRESSURE / TEMP / LOADPart 107 weather and performance
The drone is on the ground. The air thinks it is much higher.
Change the launch conditions, watch three altitudes separate on one true MSL scale, and learn what thin air asks from an electric drone.
The mental model
One field. Three altitude ideas.
Field elevation locates the ground. Pressure altitude describes the pressure level. Density altitude adds temperature so you can reason about aircraft performance.
Pressure altitude
Field elevation corrected to 29.92
Low pressure moves pressure altitude above the field. High pressure can move it below the field.
Density altitude
Pressure altitude corrected for temperature
A performance description of how dense the air behaves, not a height shown by the drone.
Interactive atmosphere lab
Change one variable. Watch the performance altitude move.
Start with a preset, then isolate elevation, pressure, or temperature. The math is intentionally visible so this remains a learning tool, not a mystery calculator.
Atmosphere instrument
Make the invisible altitude visible
Set the field, pressure, and temperature. The numeric result follows the FAA-style approximation shown below. Humidity and load stay qualitative.
Training presets
Inputs
Current launch conditions
The launch-site elevation above mean sea level.
010000
Use the current local aviation pressure setting.
28.531
Use current temperature at the launch site.
-2050
Qualitative compounding indicator. It does not change the numeric result here.
0100
Training indicator relative to your aircraft and mission, not a universal payload limit.
0100
Approximate density altitude
8,760 ft
Very high
Treat performance margin as a primary go or no-go issue. Do not rely on this approximation in place of manufacturer limits or measured aircraft behavior.
Pressure altitude
5,430 ft
ISA temperature
4.2 C
Temperature departure
+27.8 C
Approx. density altitude
8,760 ft
From field elevation
+3,330 ft
Training band
Very high
Scaled vertical profile
One MSL axis, three different altitudes
Dry air
LOWHumidity adds little qualitative concern in this scenario.
Humidity is intentionally not included in this simplified numeric approximation. Moist air can be less dense than dry air, so use this as a compounding caution only.
Working load
MODERATEKeep payload, accessories, wind, and reserve in the same performance check.
Load is not part of the altitude formula. Compare actual takeoff weight and configuration with the manufacturer documentation for the exact aircraft.
Approximation, not a performance chart
The risk band is a training aid, not an FAA operating limit or manufacturer threshold. Use current weather and the aircraft manual, and keep enough margin to stop the mission when the aircraft response is not normal.
Transparent approximation
The three lines behind the instrument.
This is a standard training approximation. It is useful for understanding direction and scale, but it does not replace an official density-altitude value, aircraft performance data, or manufacturer limitations.
- 01
Pressure altitude
field elevation + (29.92 - altimeter) x 1,000 - 02
ISA temperature
15 - 1.98 x pressure altitude in thousands - 03
Density altitude
pressure altitude + 120 x (OAT - ISA temperature)
Electric drone translation
Electric motors do not cancel thin air.
A battery-powered motor does not lose combustion horsepower in the piston-engine sense. The propeller still has fewer air molecules to accelerate, and the complete aircraft still needs enough thrust and thermal margin for the mission.
The propellers move less air
Thin air contains fewer air molecules. At the same propeller speed, the rotor system can produce less thrust than it would in denser air.
Hover may demand more power
The flight controller may command more throttle to hold position. That can reduce reserve and increase heat without creating one universal battery-loss percentage.
Climb and control margin can shrink
Payload, wind, turbulence, aggressive maneuvering, and a high-density-altitude day can all ask for the same limited thrust margin at once.
Practical go or no-go
Turn the number into a launch decision.
Density altitude is one performance input. Wind, turbulence, terrain, battery condition, configuration, people, and recovery options belong in the same decision.
- 1
Use current inputs
Get field elevation, the current local altimeter setting, and current outside air temperature. Do not reuse yesterday's weather.
- 2
Read the aircraft documentation
Compare the conditions, takeoff weight, temperature, and operating altitude with the manual for the exact aircraft and battery.
- 3
Remove optional load
Leave unnecessary mounts, guards, payload, and accessories on the ground when the mission can be completed without them.
- 4
Plan the demanding leg
Account for climb, upwind return, turbulence, terrain, and any point where the aircraft must arrest a descent or hold position.
- 5
Protect the battery
Start with a healthy pack at an appropriate temperature. Heat, cold, age, imbalance, and high current demand can reduce usable margin.
- 6
Prove response close in
Use a short, low-risk control check near the launch point. Stop if power, climb, temperature, battery, or control behavior is abnormal.
What the approximation includes and leaves out.
Included
Field elevation, altimeter setting, ISA temperature at pressure altitude, and outside air temperature.
Qualitative only
Humidity and relative payload or load. Neither changes the displayed density-altitude number.
Not predicted
Battery duration, range, maximum payload, climb rate, motor temperature, or any exact aircraft-performance loss.
Apply the weather model
Decode the report, then judge the aircraft.
Use the METAR lab to find temperature and altimeter setting, then answer weather and performance questions without the calculator.