AA.VI.D.K1
D
What does AA.VI.D.K1 mean?
Procedures and limitations associated with a nonprecision approach, including the differences between Localizer Performance (LP) and Lateral Navigation (LNAV) approach guidance..
- Area of Operation
- VI
- Task
- D
- 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 an RNAV (GPS) approach, you must understand what your navigation display is telling you at each phase: the active mode (e.g., terminal vs. approach mode), sensitivity annunciations, and RNP value, since the required lateral accuracy tightens as you transition from enroute through the final approach segment—know how to recognize a downgrade or loss of integrity (like RAIM failure) and what action that requires. You also need to understand the difference between ground-based (VOR/ILS) and satellite-based navigation in terms of signal source, error sources, outages/NOTAMs, and required equipment checks, so you can judge whether the navigation data you're using is valid and appropriate for the approach flown. Finally, a stabilized approach means arriving at a target airspeed, configuration, and descent rate early and maintaining it consistently to touchdown, using energy management (pitch, power, drag) rather than large late corrections—if the approach isn't stabilized by the appropriate point, the correct decision is to go around. Tie these together: the approach task is really testing whether you can trust and interpret your navigation guidance while also flying a disciplined, stable profile all the way down.
Why students miss this
Students often mix up what each navigation mode annunciation is actually telling them—confusing lateral sensitivity changes (like the transition from terminal to approach RNP) with vertical guidance status, or assuming GPS integrity monitoring (RAIM/SBAS) works the same way in all phases of flight. Another common trap is treating a stabilized approach as just a set of numbers to hit rather than an ongoing energy management process, so when asked what to do when a parameter drifts, they pick the answer that 'fixes the number' instead of the one that addresses the underlying energy state.
Focus on: Study how annunciations and RNP values change automatically as you sequence through an RNAV approach, and practice thinking of a stabilized approach as continuous energy management rather than a checklist of static targets.
🎯 Test yourself on this topic
Question 1 of 2In addition to the localizer, glide slope, marker beacons, approach lighting, and HIRL, which ground components are required to be operative for a Category II instrument approach to a DH below 150 feet AGL?
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Drill this area until it sticks
AA.VI.D.K1 came from a question you missed on the FAA Airline Transport Pilot Multiengine Airplane knowledge test. Take a free, ACS-aligned Equipment, Navigation, and Facilities quiz — instant scoring, explanations, and the cited FAA reference behind every answer.
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.
Study this concept
Plain-English explanations of the key ideas behind AA.VI.D.K1, grounded in the FAA handbooks.
Related ACS codes in D
Other elements the FAA tests under this same Task — review them together.
Common question
What's the difference between RAIM and SBAS for approach integrity monitoring?
RAIM is a receiver-based check using only GPS satellite geometry to detect faults, while SBAS uses ground reference stations and a satellite-based correction/integrity signal to provide more precise and reliable monitoring, often enabling lower approach minimums.
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.D.K1. 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.