Lesson 4 of 4 — Module 5: Airspace, services & transponders

Transponder squawk codes

Assigned squawks, Mode C altitude reporting, listening squawks, and the emergency codes — confirming and reading back a squawk.

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Transponder squawk codes — narrated, hands-free

Squawk (SSR) codes

7700Emergency — distress or urgency.

7600Radio (communications) failure.

7500Unlawful interference (hijack).

7000Conspicuity — the standard squawk when not given a discrete code.

Select Mode C (altitude reporting — “squawk Charlie”) unless told otherwise. A frequency-monitoring code (“listening squawk”) is a discrete code you set while just listening out on a unit's frequency, so they know you're monitoring without calling. Always read SSR instructions back, e.g. “squawk 6171” → “6171, G-ABCD”.

Coming soon: Verify the 2000 conspicuity code against a source before adding it.

Finished this lesson?

Next lesson: Emergencies — PAN and MAYDAY →

Study aid only — always defer to CAP 413 and current official publications, and to your instructor and examiner.

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