Avionics Fundamentals — FRNAS Aviation Library

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Publisher

Jeppesen

Focus

Avionics

Level

Intermediate

Category

Aircraft Systems

About This Book

Avionics Fundamentals by Jeppesen is the comprehensive reference for understanding the electronic systems that equip modern aircraft. As cockpits have evolved from steam gauges to glass displays and integrated avionics suites, pilots and technicians alike need a solid foundation in how these systems work.

This book covers the full spectrum of avionics: from the radio communication systems pilots use every day, to the sophisticated navigation and autopilot systems that make modern flight possible. It explains both the theory behind these systems and their practical operation, making it valuable for pilots who want to truly understand what their equipment is doing — not just how to use it.

Chapter Breakdown

Ch. 1

Automation Mastery: Three Pillars

The Advanced Avionics Handbook (FAA-H-8083-6) defines automation mastery through three pillars: (1) Understand what the automation is doing and why (mode awareness); (2) Detect deviations from intended state through active monitoring; (3) Intervene decisively when automation behavior is unexpected. The book stresses that the pilot is always the "manager" of automation, never a passenger. Complacency and mode confusion are identified as the two primary glass-cockpit accident causes.

Ch. 2

Primary Flight Display: ADC, AHRS & Failure Diagnosis

PFD (Primary Flight Display) integrates: Air Data Computer (ADC) — feeds airspeed, altitude, VSI; AHRS (Attitude Heading Reference System) — solid-state gyros + accelerometers for pitch, roll, heading. Red-X failure flags: a red X through airspeed = ADC pitot failure (use GPS groundspeed reference); a red X through attitude = AHRS failure (revert to backup AI). HSI on PFD: combines compass, CDI, and glideslope. Reversionary mode: single display showing both PFD and MFD content.

Ch. 3

GPS, WAAS & FMS CDI Scaling

WAAS (Wide Area Augmentation System) corrects GPS errors to <3 meter accuracy, enabling LPV (Localizer Performance with Vertical guidance) approaches with 200 ft DH. CDI scaling changes automatically: En Route = ±2.0 NM full-scale; Terminal (within 30 NM of destination) = ±1.0 NM; Approach active = ±0.3 NM. FMS flight plan construction: use direct-to, airways, fixes, and procedure legs. RAIM alert: if RAIM is not available within 15 minutes of ETE to destination, cannot execute GPS approach.

Ch. 4

Autopilot, FMA Monitoring & VS vs. FLC

FMA (Flight Mode Annunciator): always verify active modes match intended modes after each selection. Autopilot modes: HDG (holds selected heading), NAV (tracks CDI course), APR (couples to ILS/GPS approach), ALT (holds altitude), VS (Vertical Speed — set FPM target), FLC (Flight Level Change — set airspeed, power controls VS). VS mode: at risk of stall if airspeed decreases unmonitored. FLC mode: more energy-efficient for climbs/descents. TOD rule of thumb: (altitude to lose / 1000) × 3 NM start of descent.

Ch. 5

TAWS, Datalink Weather & TCAS

TAWS (Terrain Awareness Warning System): uses GPS + terrain database to generate terrain alerts. Class A TAWS required for turbine aircraft with 6+ seats. Class B for smaller aircraft. Warnings: "Terrain, terrain, pull up!" (immediate action — full power + pitch up). Datalink weather (XM/FIS-B): 15-20 minute latency; never use for penetration decisions — use ATC, onboard radar, or PIREPs for real-time convective decisions. TCAS II: Resolution Advisories (RA) — always follow RA over ATC instruction during active alert. TA = Traffic Advisory (monitor); RA = Resolution Advisory (maneuver required).

Key Avionics Rules

CDI Scaling: En Route 2.0 NM / Terminal 1.0 NM / Approach 0.3 NM

CDI sensitivity automatically increases as the aircraft transitions from en-route to terminal to approach phases. A one-dot deflection means very different cross-track error at each phase. Never compare CDI deflections across phases.
TOD: (Altitude to Lose / 1,000) × 3 NM

Top of Descent calculation: descending 10,000 ft at 3° descent angle requires starting the descent 30 NM before the destination. Descent rate rule: GS (kts) × 5 = required descent rate in FPM for a 3° glidepath.
Datalink Weather Has 15-20 Minute Latency

XM and FIS-B weather products are not real-time. Convective cells can develop, intensify, or move significantly in 20 minutes. Use datalink for strategic planning, not for penetration decisions near active thunderstorms.
Always Follow TCAS RA — Even Against ATC

During a TCAS Resolution Advisory, follow the RA immediately and completely. Notify ATC as soon as able. TCAS is mandatory for all turbine-powered aircraft with 10+ seats operating in US airspace; never disregard an active RA.

The glass cockpit does not reduce the pilot's workload unless the pilot understands it completely — a misunderstood automation mode creates more confusion than the steam gauges it replaced.

Who Should Read It

This book is essential for instrument-rated pilots who want to understand what is behind the glass panels they fly every day. It is also the primary study text for aviation maintenance technicians working toward their avionics certification. For any pilot flying modern glass cockpit aircraft — from a Garmin G1000 to a full airline FMS — a solid understanding of avionics fundamentals makes you a more capable and safer aviator.

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