Airspace Classification and Operating Requirements›Airspace Operational Requirements›UA.II.B.K5

Exam Weight: 15-25%

Refs: 14 CFR part 71; AC 107-2; AIM; FAA-H-8083-25; FAA-G-8082-22; SAFO 10015

UA.II.B.K5: The NOTAM system, including how to obtain an established NOTAM through Flight Service.

ACS Area II — Airspace Classification and Operating Requirements Task B: Airspace Operational Requirements References: 14 CFR part 71; AC 107-2; AIM; FAA-H-8083-25; FAA-G-8082-22; SAFO 10015

Key Concepts

What NOTAMs Mean for Your Preflight Planning

NOTAMs can directly affect navigation services you may rely on, especially GPS. Before flight, operators using GPS for navigation are expected to confirm GPS integrity through RAIM (Receiver Autonomous Integrity Monitoring) prediction using current satellite information. That satellite status is disseminated via NOTAMs and NANUs and must be considered when determining whether RAIM will be available for the planned route and time. If a continuous loss of RAIM of more than five minutes is predicted for any part of the intended flight, delay, cancel, or reroute the flight so requirements can be met. This makes NOTAM awareness a go/no-go factor, not just a “nice to know” item. For exam purposes, be ready to identify that NOTAMs are a key input to RAIM prediction and that an extended predicted RAIM outage (>5 minutes) requires a change in your plan. ^[6]

You can satisfy RAIM prediction requirements in several ways. Critically, one approved method is to contact a Flight Service Station (FSS) to obtain non-precision approach RAIM for your intended route and time. When you do this, the RAIM status provided by FSS reflects the latest GPS constellation status, which includes NOTAMs and NANUs. In practice:

State your route and time window so FSS can check RAIM for the intended flight period using current satellite information and NOTAMs.
If you are using receiver or model-specific prediction, ensure you account for NOTAMs/NANUs; RAIM must be available where required at the estimated time of arrival. If a predicted continuous loss exceeds five minutes, adjust your plan (delay, cancel, or reroute). ^[6]

Remember that FSS is also the FAA point of contact you must notify when you cancel or complete an activated flight plan (per 14 CFR 91.153 and 91.169). Knowing how and when to contact FSS is foundational to obtaining services like RAIM/NOTAM information and for closing flight plans. ^[7]

Exam tip: If asked “how to obtain an established NOTAM through Flight Service,” a correct response is to contact an FAA Flight Service Station and request RAIM information for your route/time, which is derived from current GPS satellite status including NOTAMs/NANUs. ^[6]

Applying NOTAM Awareness in Airspace Operations

NOTAM-driven navigation impacts are most consequential in and around controlled airspace where traffic density and ATC procedures heighten the need for dependable navigation:

Class A spans from 18,000 feet MSL up to and including FL 600 and includes airspace overlying the waters within 12 NM of the U.S. coast. All operations in Class A are IFR, so loss of required RAIM could be operationally critical. ^[1]
Class E typically extends up to, but not including, 18,000 feet MSL. Understanding where controlled airspace begins helps you anticipate where navigation service reliability matters most to system users you may be sharing airspace with (e.g., near terminal areas). ^[3]
In Class C, establish and maintain two-way communications prior to entry; controllers may manage dense mixed operations. There is also a procedural “Outer Area,” normally 20 NM from the primary Class C airport, where participation in Class C services is expected. Reliable navigation is important when transitioning these busy areas. ^[4]

While small UAS typically operate at low altitudes, NOTAMs affecting GPS integrity can still influence mission reliability (for example, navigation accuracy, return-to-home functions, and geo-fencing). Build a habit pattern: check for GPS-related NOTAMs via an approved RAIM prediction method, and use FSS as a direct source when needed. If RAIM is predicted unavailable for more than five minutes during your planned operation, adjust your plan accordingly. ^[6]

Practical Exam Takeaways

NOTAMs feed GPS RAIM prediction; you must account for current satellite status, including NOTAMs/NANUs, when verifying RAIM. If a continuous RAIM loss >5 minutes is predicted, delay, cancel, or reroute. ^[6]
To obtain NOTAM-informed RAIM status, contact a Flight Service Station for non-precision approach RAIM for your route/time. ^[6]
Know how to reach and use FSS; it is also the facility you must notify when canceling or completing an activated flight plan under 14 CFR 91.153/91.169. ^[7]
Recognize where navigation integrity is operationally critical in controlled airspace (e.g., Class A from 18,000 feet MSL to FL 600; Class E up to but not including 18,000 feet MSL; Class C with a 20 NM procedural Outer Area). ^[1] ^[3] ^[4]

Test Yourself

UA.II.B.K5

No practice questions are currently available for this specific knowledge element.

UA.II.B.K4: Potential flight hazards.

UA.II.B.K6: Operator equipment for night flight.