ICAO Diversion Scenarios

Diversion scenarios are among the most comprehensive evaluation tasks in the ICAO Aviation English assessment. Raters evaluate how clearly and decisively pilots can explain why an aircraft cannot proceed to its destination, justify the selection of an alternate aerodrome, negotiate revised routings and descent profiles with Air Traffic Control (ATC), and manage crew coordination under operational time constraints.

This page details core diversion scenario categories, structured radiotelephony templates, aeronautical decision-making frameworks, and model speaking responses to help pilots achieve ICAO Level 4, Level 5, or Level 6.

Step 1: The 4-Step Diversion Decision Framework

When presented with a diversion prompt in the oral exam, organize your response logically to show clear airmanship and structured plain English fluency:

• 1. Identify the Trigger: State the root reason for leaving the planned flight path (e.g., severe weather below minima, technical malfunction, medical emergency, fuel state).
• 2. Assess Alternate Suitability: Evaluate candidate airfields considering runway length, approach aids, current weather trends, and emergency services.
• 3. Review Fuel & Performance: Verify that burn-off to the alternate guarantees touchdown with required final reserve fuel intact.
• 4. Coordinate & Execute: Request ATC clearance, deliver a NITS briefing to the cabin crew, update passengers, and notify company operations.
• ICAO Diversion Topics
• ICAO Problem Solving
• Pilot Decision Making Discussion

Step 2: Core Diversion Scenario Categories

Examiners use listening audio recordings, situational role-plays, and picture tasks based on standard diversion triggers:

Adverse Weather & Below-Minima Conditions

• destination airport affected by dense radiation fog reducing RVR below landing minimums
• active squall lines or microbursts blocking approach corridors and forcing a turn to an inland alternate
• severe crosswind gusts exceeding certified aircraft landing limits on single-runway airfields
• ICAO Weather Scenarios
• ICAO Weather Topics
• Weather Safety Discussion

Medical Emergencies & Passenger Disruptions

• passenger suffering suspected acute coronary syndrome or stroke requiring urgent hospital intervention
• violent or unruly passenger behavior compromising safety and requiring immediate law enforcement meet
• selecting an en-route alternate with direct ground paramedic access and adequate medical facilities
• Passenger Emergency Scenarios
• ICAO Passenger Topics
• ICAO Emergency Scenarios

Technical Malfunctions & System Degradation

• single engine shutdown or major hydraulic circuit loss requiring precautionary landing at nearest suitable field
• loss of RNAV/RNP guidance in IMC requiring an airport equipped with conventional ILS or VOR approaches
• flight control / flap asymmetry requiring an extended runway with long stopping margins
• Technical Failure Scenarios
• Technical Problem Topics
• Technical Problem Picture Description

Airfield Closures & Fuel Depletion

• destination runway blocked by a disabled aircraft or sudden disabled vehicle incursion
• extended holding times consuming contingency fuel and forcing a diversion at minimum diversion fuel
• curfew closures or sudden military airspace restrictions requiring rerouting to commercial alternates
• ICAO Fuel Scenarios
• ICAO Fuel Topics
• ICAO Delay Topics

Step 3: Communicating Diversions to ATC

Deliver clear, concise radiotelephony calls when initiating route changes and requesting alternate clearances:

• Declaring Weather Diversion: "Radar, FastAir 312, destination weather below landing minima. Request diversion to our alternate, Cologne, direct waypoint BAMKI."
• Declaring Medical Diversion (PAN-PAN): "PAN-PAN, PAN-PAN, PAN-PAN, Carrier 504, passenger medical emergency. Request immediate descent and vectors to divert to Frankfurt."
• Inquiring About Alternate Conditions: "Control, request latest METAR, active runway, and expected approach type for our en-route alternate, Munich."
• Advising Fuel State on Diversion: "Advising remaining endurance is 1 hour 20 minutes, estimated fuel on touchdown at alternate 2.6 tonnes."
• ICAO Interaction
• ICAO Request Phrases
• ATC Communication Topics

Step 4: Aeronautical Decision-Making (ADM) in Alternate Selection

Structure your response during oral scenario tasks by methodically comparing operational trade-offs:

• 1. Operational Suitability: Compare runway length, surface condition, available approach lighting, and fire category (RFFS).
• 2. Weather Trends: Ensure the alternate is not deteriorating and has stable visibility and wind within crosswind limits.
• 3. Passenger & Airline Support: Consider ground handling availability, passenger accommodation, and airline maintenance capability if multiple safe airports exist.
• 4. Safety Hierarchy: Prioritize safety over commercial convenience—never select a marginal airport simply because it is a company base.
• ICAO Problem Solving
• ICAO Speaking Part 3 Problem Solving
• Pilot Decision Making Discussion
• ICAO Scenario Explanation

Step 5: Follow-Up Diversion Discussion Questions

In Part 4 of the speaking test, examiners ask detailed questions about flight planning policies, decision-making psychology, and airline operations:

• What are the most critical factors when selecting a suitable en-route alternate during long-haul flights?
• How can flight crews avoid "get-there-itis" when destination weather is fluctuating around landing minimums?
• What operational disruptions occur for airlines when an aircraft diverts to an unplanned aerodrome?
• Under what circumstances must a pilot divert immediately without entering a holding pattern?
• How should flight crews handle communication with concerned passengers following an unexpected diversion?
• Flight Operations Discussion
• Aviation Safety Discussion
• Pilot Experience Discussion
• ICAO Speaking Part 4 Discussion