Navigation Systems and Radar Services

Work in a fixed order the student can repeat every time:

1. Tune the frequency
2. Identify by Morse code audio — an unidentified station is an unusable station
3. Orient — twist the OBS to center the needle and read TO or FROM; that gives the radial you are on
4. Determine the course to fly and intercept it
5. Track with a wind correction, not a chase

The insight most students are missing: the VOR indication is independent of aircraft heading. The CDI shows where you are relative to the selected course, not where you are pointed. Teach that before you teach intercepts and half the confusion disappears.

When the OBS setting and the direction of flight disagree — flying "TO" a station with a FROM course selected, or vice versa — the needle indicates backward, so a correction toward the needle takes you further off course.

For students the fix is procedural: set the course you intend to fly, and confirm the TO/FROM flag agrees with what you are doing. PHAK ch. 16 makes the same point about VOR tracking generally — flying toward the needle works when the selected course matches the direction of flight, and produces reverse action when it does not.

The TO/FROM flag flips, usually preceded by the needle becoming increasingly sensitive as the airplane nears the station, and by passage through the cone of confusion where the indication is briefly unreliable. AI.II.H.S4 asks you to recognize and describe the indication of station or waypoint passage — so teach both the VOR version and the GPS version (the waypoint sequences and the next leg's desired track appears).

Teaching technique: have the student call station passage out loud, then log the time. It converts a passive indication into an active navigation event.

The 91.171 checks are an IFR requirement — there is no equivalent regulatory check for VFR flight:

• VOT
• Designated ground checkpoint
• Airborne checkpoint
• Dual VOR cross-check
• Repair-station check

But teach it anyway, because the underlying concept transfers: a navigation source that has not been verified is a navigation source you should not bet on. Teach the student a habit of cross-checking the VOR against pilotage landmarks and against GPS, and of noticing when the answers disagree.

Receiver Autonomous Integrity Monitoring — the receiver's ability to check the consistency of the satellite signals it is using and warn the pilot when the position solution may not be trustworthy. It requires redundant satellites; with the minimum number in view the receiver can compute a position but cannot verify it.

The VFR teaching point is simpler than the mechanism: a GPS can be confidently wrong. Teach the student what a loss-of-integrity annunciation looks like on their specific box, and teach them to notice when the moving map disagrees with the window.

Read the manufacturer's supplement — the Task note directs the evaluator to do the same. The recurring issues to teach:

• Database currency — an expired database can carry an obstacle, a waypoint, or an airport that no longer exists as charted
• Authorized use — VFR-only receivers, including handhelds and tablets, are supplemental aids; they are not approved for IFR navigation
• Installation-specific limitations — what the box may legally be used for is in the AFM supplement, not the user's guide

AC 91-78 addresses using an electronic flight bag in place of paper charts — worth teaching your student, and worth being able to name on the checkride.

The tablet is a single point of failure that fails in exactly the conditions that stress the pilot: heat, battery, and glare. Teach the mitigations as rules:

• A backup — a second device, or paper charts
• A power source and a plan for when it fails
• Overheat management — out of direct sun, and out of the glareshield
• Preflight download — charts, plates, and weather loaded before engine start, so the flight does not depend on connectivity
• A mounted position that does not block the scan or the controls

And the discipline that matters most: the EFB is in the scan, not the focus. PHAK ch. 14 lists concentration on flight instruments or tablets as the first limitation on scan frequency.

• Traffic advisories (flight following) — workload permitting; the controller points out traffic, but see-and-avoid remains the pilot's responsibility under 91.113(b)
• Safety alerts — issued when the controller observes the aircraft at an altitude that places it in unsafe proximity to terrain, obstructions, or other aircraft
• Vectors — when requested or when necessary
• TRSA service — participation is voluntary, but pilots operating VFR are encouraged to contact radar approach control and take advantage of TRSA service (PHAK ch. 15)
• Radar assistance in an emergency, including help locating an airport or navigating out of deteriorating weather

PHAK ch. 14 makes the case for using it: proper communication with ATC has benefits, and flight following often makes the controller's job easier because they can better integrate VFR and IFR traffic.

• Mode A — reports the assigned code only. Mode C — adds pressure altitude. Mode S — adds a discrete aircraft address and data link capability

• 91.215(b) — an operable transponder with Mode A 4096-code or Mode S capability and automatic pressure altitude reporting (Mode C) is required in:

  • Class A, B, and C airspace
  • All airspace within 30 NM of an appendix D, section 1 airport, from the surface up to 10,000 ft MSL
  • All airspace above the ceiling and within the lateral boundaries of a Class B or Class C area, up to 10,000 ft MSL
  • Plus the remaining 91.215(b)(5) altitude cases

  Limited exceptions exist for aircraft never certificated with an engine-driven electrical system, balloons, and gliders

• 91.225 and 91.227 — where ADS-B Out is required and the performance requirements it must meet

• Emergency codes — 7500 hijack, 7600 lost communications, 7700 emergency; 1200 for VFR

Teach the student to squawk and talk before they need to: a transponder code and a radar identification make an emergency dramatically easier for everyone.

The one that matters: in certain airspace, not all aircraft will be equipped with ADS-B Out or transponders and will not be visible on your display (PHAK ch. 14). A clean screen is not a clear sky.

How to use the display well is covered under Task II.B. What this Task adds is that the limitation above is a risk element — you're being asked how you manage it, not just whether you know it.

The instructional problem is that the failure mode is invisible. A student who scans outside and sees nothing gets no reinforcement; a student who checks the display and sees nothing gets an immediate, satisfying confirmation. The display trains the wrong habit all by itself, and it does it through the law of effect — the behavior with the satisfying outcome is the one that repeats.

Three mitigations to be able to name:

• Order the scan. Outside first, display second, as confirmation. Never the reverse, and enforce it out loud on early flights
• Fly with it off, deliberately. At least once, run a pattern or a practice-area session with the traffic page dark. Students who have never done this don't believe the limitation, they only recite it
• Point out the non-participants. When you spot a no-radio taxiing aircraft, an ultralight, or a glider that never appears on the screen, say so at the time. One real example outweighs the caveat (law of intensity)

Build the mental picture first, then the procedure.

1. Where am I? Center the needle, read the radial. Say it out loud.
2. Where do I want to be? Set the course you intend to track.
3. Which way is it? Needle deflection tells you the direction of the course from your position.
4. How aggressively? Choose an intercept angle proportional to the distance — a large angle when far, a smaller one when close.
5. Fly the heading, watch the needle, lead the turn.

Then apply the same five questions to GPS, where the box answers 1 through 3 for you and the student's job is 4 and 5. Teaching the same structure for both systems is transfer of learning (AIH ch. 2) — the student is not learning two skills, they are learning one skill twice.

Teach three levels of automation and the rule for moving between them:

• Level 1 — hand-flying with raw data
• Level 2 — flight director or GPS guidance, hand-flown
• Level 3 — autopilot coupled

The rule: when the system does something you did not expect, step down a level immediately and figure it out from there. Never troubleshoot at level 3.

Then require the student to demonstrate level 1 competency in the same airplane. A pilot who cannot navigate without the magenta line has not learned navigation; they have learned an interface.

Teach a hierarchy the student can execute while task-saturated:

1. Aviate. Wings level, heading, altitude.
2. Note the time and the last known position. The dead-reckoning fix is only as good as the moment you started it.
3. Switch to the backup. A second nav source, pilotage against landmarks, or the DR heading and estimate.
4. Ask for help. Radar services can provide a position and vectors; that is what they are for.

For VFR students the most common version of this is not a signal failure at all — it is a tablet that overheated or a battery that died. Same procedure, and it is the reason you require a backup.

A structured initial call the student can build under pressure: who you are calling, who you are, where you are, what you want. Then the readback discipline that Task II.C depends on — read back everything that is a clearance or an instruction, with your call sign, so ATC can catch the misunderstanding (PHAK ch. 14).

Two specific teaching points:

• Listen before transmitting, and monitor instructions issued to other aircraft — especially when another aircraft has a similar sounding call sign (PHAK ch. 14)
• "Unable" is a complete sentence. Students accept vectors and altitudes they cannot safely fly because they think a controller instruction is a command. Teach the 91.3(a) framing: the PIC is directly responsible for, and is the final authority as to, the operation of the aircraft.

By assigning the workload deliberately rather than letting it happen. Techniques that work:

• Set up before you need it. Tune, identify, and set the course while still in cruise and level.
• Look outside between steps. Teach a rhythm: one action inside, then eyes outside.
• Verbalize. "Tuned, identified, course set" out loud tells you the scan is being interrupted deliberately, for a bounded time.
• You clear while the student programs, and you say so — with a positive exchange of controls if the student needs both hands (AIH ch. 9).

The standard remains roughly 90 percent of attention outside with instruments validating (AFH ch. 3). A student heads-down programming a GPS in the practice area has inverted it, and only the instructor will notice.