science

Outside air temperature

Outside air temperature is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Outside air temperature rather than just read about it. In short: In aviation terminology, the outside air temperature (OAT) or static air temperature (SAT) refers to the temperature of the air around an aircraft, but unaffected by the passage of the aircraft through it. Aviation usage The outside air temperature is used in many calculations pertaining to flight planning, some of them being takeoff performance, density altitude, cruise performance and go-around performance.

Key takeaways

Outside air temperature belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Outside air temperature to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Outside air temperature from memory before moving on to harder problems.

Reference excerpt

Aviation usage The outside air temperature is used in many calculations pertaining to flight planning, some of them being takeoff performance, density altitude, cruise performance and go-around performance. In most texts, the abbreviation, "OAT" is used.

Units Most performance and flight planning graphs and tables use either degrees Celsius or Fahrenheit or both. The Kelvin scale, however, is used for Mach number calculations. For example, the speed of sound in dry air is

c = 38.945 K , {\displaystyle {c}=38.945{\sqrt {K}},}

where:

c {\displaystyle c} is the speed of sound in knots,

K {\displaystyle K} is the outside air temperature in kelvins.

Sources Outside air temperature can be obtained from the aviation meteorological services, on the ATIS or measured by a probe on the aircraft. When measured by the airplane's probe in flight, it may have to be corrected for adiabatic (ram effect) rise and friction, particularly in high performance aircraft. Therefore, the outside air temperature is usually calculated from the total air temperature. ATIS temperture represents the temperature at the elevation of the atis reporting station ie the surface elevation.

See also Acronyms and abbreviations in avionics Hot and high

References

Worked examples

Example 1 — a first encounter with Outside air temperature

Start with the simplest possible case. Write down what Outside air temperature claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Outside air temperature before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Outside air temperature ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Outside air temperature

In research: Outside air temperature appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Outside air temperature in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Outside air temperature is common in secondary-school and first-year university syllabi. It links to neighbouring topics Atmospheric temperature, Aviation meteorology, so understanding it makes those chapters shorter.
In everyday life: Look for Outside air temperature outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Outside air temperature in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Outside air temperature means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Outside air temperature out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Outside air temperature in simple terms?

In aviation terminology, the outside air temperature (OAT) or static air temperature (SAT) refers to the temperature of the air around an aircraft, but unaffected by the passage of the aircraft through it. Aviation usage The outside air temperature is used in many calculations pertaining to flight…

Why does Outside air temperature matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Outside air temperature?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Outside air temperature.