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How do high temperature, high elevation, and high humidity affect aircraft performance?

Choices

  • They lower density altitude and improve climb performance

    These factors raise density altitude, they do not lower it.

  • They raise density altitude and degrade takeoff and climb performancecorrect

    Hot, high, and humid air is less dense, raising density altitude and reducing lift, thrust, and power.

  • They have no effect on a normally aspirated engine

    Less dense air reduces the power a normally aspirated engine produces.

  • They increase air density and available thrust

    These conditions decrease air density, not increase it.

Why

High temperature, elevation, and humidity make the air less dense, raising density altitude. The wing produces less lift, the propeller is less efficient, and the engine makes less power, so takeoff and climb performance degrade.

FAA source: PHAK Ch. 12 / Aviation Weather Handbook FAA-H-8083-28browse the reference library →

Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.

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