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FAA ACS Code

AA.VI.C.K4

C

Certificate: Airline Transport Pilot – AirplaneType: Knowledge

What does AA.VI.C.K4 mean?

Two-way radio communication failure procedures during an arrival..

Area of Operation
VI
Task
C
Element type
A Knowledge element — a fact, concept, or procedure the FAA expects you to know and that the knowledge (written) test draws questions from.

What you need to know

For arrivals, you need to read a STAR chart and cross-reference it with the enroute chart and airport diagram to understand routing, altitude/speed restrictions, and transitions, then verify your FMS/GPS is loaded and sequencing correctly to match the cleared procedure. Know who's responsible for what: ATC assigns and amends clearances while you're responsible for flying the charted or amended path precisely and questioning anything unclear before it becomes a problem. If you lose two-way radio communication during the arrival, you follow the last clearance received combined with the STAR's published routing and altitudes, proceeding as expected by ATC rather than improvising. Also understand the basics of your navigation source—whether ground-based or satellite-based—including how to confirm signal integrity, recognize outages or interference, and know when you must use an alternate means of navigation.

Why students miss this

Students often treat STAR charts as purely lateral navigation guides and miss the altitude and speed restrictions coded into the chart notes or FMS legs, so they misjudge what's expected on a given transition. They also frequently mix up standard lost-comm procedures with what to do when a STAR restriction and a clearance amendment conflict, leading them to pick the wrong course of action.

Focus on: Practice reading a STAR chart's altitude/speed constraints and cross-check how those constraints load into an FMS or GPS so you understand what the box is actually commanding versus what ATC expects.

Missed this on your test?

Drill this area until it sticks

AA.VI.C.K4 came from a question you missed on the FAA Airline Transport Pilot Multiengine Airplane knowledge test. Drill ACS-aligned practice questions with AI explanations and the cited FAA handbook reference behind every answer — free to start.

Missing it isn't a verdict on you — it's a sign your prep skipped the why behind it. Memorizing answer letters is exactly what leaves gaps like this. Here, every answer explains the reasoning and cites the FAA source it comes from, so the concept holds on test day and at the checkride oral.

Try a free practice test →Airline Transport Pilot Multiengine Airplane prep

Study this concept

Plain-English explanations of the key ideas behind AA.VI.C.K4, grounded in the FAA handbooks.

Related ACS codes in C

Other elements the FAA tests under this same Task — review them together.

Common question

If ATC clears me for a STAR but doesn't mention the altitudes on the chart, am I supposed to follow the published restrictions anyway?

It depends on how the clearance is worded and whether the STAR name includes a transition or 'descend via' phrasing; you should always check current FAA guidance and the chart's notes to know exactly when published altitudes/speeds become mandatory.

What is an FAA ACS code?

The FAA's Airman Certification Standards (ACS) break each certificate into Areas of Operation, Tasks, and specific Knowledge (K), Risk Management (R), and Skill (S) elements. Every knowledge-test question maps to one code like AA.VI.C.K4. When you miss a question, your Airman Knowledge Test Report lists its code so you know exactly what to review.

Have a whole list of codes from your report? Paste them all into our free ACS code lookup to see every weak area at once — or browse the aviation glossary for plain-English definitions.

All ACS documents at faa.gov ↗