Radio Navigation and Area Navigation (RNAV) Planning
Core concepts
Radio navigation includes VOR, DME, NDB, ILS, and GNSS. RNAV allows aircraft to fly on any desired path within the coverage of navigation aids or GNSS. Key concepts: waypoint types (fly-by, fly-over), RNAV route spacing, RNP (required navigation performance), and the distinction between RNAV and RNP (RNP includes on-board performance monitoring and alerting).
Traps
Questions test: the difference between RNAV and RNP; the meaning of fly-by versus fly-over waypoints; the effect of wind on RNAV tracking; and the requirement for GNSS integrity monitoring (RAIM). Also watch for the difference between 'RNAV 5' and 'RNAV 1' specifications.
Worked example / rule of thumb
Rule: for RNAV, the cross-track error tolerance is defined by the navigation specification. Example: RNAV 5 requires 5 NM accuracy; RNAV 1 requires 1 NM. When planning an RNAV route, verify that the aircraft's navigation equipment meets the specification and that RAIM is available for the intended route and time.
Flight Monitoring, In-flight Replanning and Diversion
Core concepts
In-flight monitoring compares actual progress (fuel, time, position) with the plan. Triggers for replanning: fuel below contingency, weather deterioration, NOTAM changes, or ATC restrictions. Diversion planning requires selecting an alternate, computing fuel to reach it, and notifying ATS.
Traps
Questions test: the decision point for diversion (fuel vs weather); the requirement to notify ATS; the fuel computation for the diversion; and the difference between a 'planned alternate' and an 'en-route alternate'. Also watch for the 'point of no return' (PNR) and 'equal time point' (ETP) concepts.
Worked example / rule of thumb
Rule: diversion fuel = distance to alternate ÷ groundspeed × fuel flow. Example: alternate 120 NM away, GS 150 kt → 0.8 h; fuel flow 40 kg/h → 32 kg. Add final reserve 20 kg → 52 kg required. If remaining fuel is less than this, declare an emergency or divert immediately.
Human Factors and Decision-Making in Flight Planning
Core concepts
Human factors in flight planning include situational awareness, workload management, decision-making models (e.g., DECIDE, FOR-DEC), and threat and error management (TEM). Common biases: confirmation bias, plan continuation bias, and optimism bias. Good planning includes setting personal minimums, using checklists, and cross-checking with another crew member.
Traps
Questions test: the difference between 'plan continuation bias' and 'confirmation bias'; the role of personal minimums; and the importance of cross-checking. Also watch for the 'hazardous attitudes' (anti-authority, impulsivity, invulnerability, macho, resignation) and their antidotes.
Worked example / rule of thumb
Rule: use the '3P' model - Perceive, Process, Perform. Example: Perceive a deteriorating weather forecast; Process the options (continue, divert, return); Perform the chosen action and monitor the result. Always set personal minimums above regulatory minima and review them before flight.