At higher altitude with lower density, to maintain the same lift at the same true airspeed, which action is required?

At higher altitude with lower density, to maintain the same lift at the same true airspeed, which action is required?

• A. Increase speed
• B. Increase wing area
• C. Increase weight
• D. Decrease speed

Answer: (A)

Lift scales with air density, velocity squared, wing area, and the lift coefficient. When you climb to higher altitude, density drops, so lift would fall unless something else is changed. To compensate for the denser-atmosphere drop, increasing velocity directly raises dynamic pressure (the V^2 term) and restores lift toward its previous value. Among the given options, increasing speed is the most straightforward way to offset the reduced density and keep lift the same. Decreasing speed would reduce lift, increasing weight would make more lift mandatory, and increasing wing area would help but isn’t the chosen option here.

Lift scales with air density, velocity squared, wing area, and the lift coefficient. When you climb to higher altitude, density drops, so lift would fall unless something else is changed. To compensate for the denser-atmosphere drop, increasing velocity directly raises dynamic pressure (the V^2 term) and restores lift toward its previous value. Among the given options, increasing speed is the most straightforward way to offset the reduced density and keep lift the same. Decreasing speed would reduce lift, increasing weight would make more lift mandatory, and increasing wing area would help but isn’t the chosen option here.