Runway Safety
Prevention of Runway Incursions
ICAO Doc 9870 • PANS-ATM ATCO Training Module
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1. Definition & Context
Based on ICAO Doc 9870 – Manual on the Prevention of Runway Incursions and related guidance.
Definition • Why this matters Use ← / → keys to change slides

Runway incursion prevention is a core part of runway safety and a direct protection against high-speed, catastrophic accidents.

ICAO Definition
Runway incursion (PANS-ATM definition):
  • Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take-off of aircraft.
Key words:
  • Any occurrence – no minimum severity.
  • Incorrect presence – something is where it should not be.
  • Protected area – runway and protected surfaces for landing/take-off.
Source: ICAO Doc 9870 / PANS-ATM definition
Why this is critical
  • Runway incursions have led to major fatal accidents.
  • With increasing traffic, the number of incursions has also increased worldwide.
  • On a runway, at least one aircraft is often at high speed – little time to correct errors.
Runway safety is a shared responsibility – pilots, controllers, vehicle drivers, aerodrome operators and regulators all form part of the defence system.

Even a low-speed ground incident can be serious, but a runway collision is usually catastrophic because of speed and mass.

Effects of Runway Incursions
Consequences of runway incursions include:
  • High risk of high-speed collision between aircraft, or between aircraft and vehicles/persons.
  • Extensive structural damage and possible hull loss.
  • High likelihood of fatalities and serious injuries.
  • Operational disruption, loss of capacity and reduced confidence in safety.
Compared with off-runway ground incidents, runway collisions generally:
  • Occur at higher speeds,
  • Involve fully fuelled aircraft,
  • Have much more severe outcomes.
Example Safety Indicators
  • States and ANSPs often track runway incursions separately as:
    • Incursions involving aircraft,
    • Incursions involving vehicles,
    • Incursions involving persons,
    • Ramp incidents causing damage/injury.
  • Typical causal factors in national data include:
    • Misunderstood communication,
    • Inadequate signage/markings/lighting,
    • Inadequate training,
    • Insufficient risk assessment,
    • Non-adherence to SOPs.
Runway = highest-risk surface
Monitor causal factors, not only counts

Most runway incursions start from communication breakdown and loss of situational awareness.

Breakdown in Communications
Common elements in communications breakdown between controllers and pilots/vehicle drivers:
  • Use of non-standard phraseology.
  • Pilot/driver fails to give correct readback.
  • Controller does not ensure the readback matches the clearance.
  • Pilot/driver misunderstands the ATC instruction.
  • Clearance intended for another aircraft/vehicle is accepted.
  • Transmissions are blocked or partially blocked.
  • Over-long, complex transmissions which are hard to follow.
These issues are often present together in a single event.
Pilot-Related Factors
  • Inadequate visibility of:
    • Runway-holding position markings,
    • Signs, lighting and guidance.
  • ATC instructions during landing roll-out (high workload, high noise).
  • Mandatory head-down tasks reducing outside scan.
  • Complex aerodrome design requiring runway crossings.
  • Incomplete, non-standard or obsolete taxi-route information.
  • Last-minute changes to taxi or departure routing by ATC.
When workload is already high, even a small ambiguity in a taxi or line-up clearance can push a crew into the wrong place at the wrong time.

Controllers, vehicle drivers and aerodrome design can all contribute to the same runway incursion if the defences are weak.

ATC-Related Factors
Typical controller-related factors:
  • Momentarily forgetting:
    • An aircraft or vehicle on the runway,
    • A runway closure,
    • A clearance already issued.
  • Failure to correctly anticipate or calculate necessary separation.
  • Inadequate coordination between controllers or between units.
  • Ground controller issuing a crossing clearance that should be issued by tower/approach.
  • Misidentification of an aircraft or its position.
  • Controller readback errors or not ensuring correct pilot/driver readback.
  • Use of non-standard phraseology.
  • Distraction, workload, experience level, inadequate training.
  • Poor line-of-sight from the tower, HMI issues, poor handover.
  • Reduced reaction time during on-the-job training situations.
Vehicle & Design Factors
  • Vehicle Driver Factors:
    • Entering the runway without clearance.
    • Not complying with ATC instructions.
    • Inaccurate reporting of position.
    • No RT equipment or training.
    • Lack of familiarization with aerodrome layout.
    • Poor knowledge of signs and markings.
    • No aerodrome map in the vehicle.
  • Aerodrome Design Factors:
    • Complex layout requiring frequent runway crossings.
    • Taxiways/roads close to the runway.
    • Insufficient spacing between parallel runways.
    • No end-around taxiways to avoid runway crossings.
    • Taxiways not intersecting the runway at right angles.
Multiple small errors → single incursion
Shared responsibility (ATC–Pilot–Vehicle–Aerodrome)

Some points on the manoeuvring area have a history or strong potential for runway incursions. These are identified as hot spots. At Guwahati, this includes TWY E and TWY G.

Hot Spots – Concept
A hot spot is a location on the movement area:
  • With a history of runway incursions or surface incidents, or
  • Where the potential for collision or incursion is known to be high,
and therefore requires heightened attention by pilots, controllers and vehicle drivers.

Common characteristics:
  • Complex or unusual geometry.
  • Intersections of multiple taxiways with runway access.
  • Areas where visibility is often reduced (fog, haze, heavy rain).
  • Changes in marking/lighting that are not intuitive.
Guwahati (VEGT) – TWY E & TWY G
  • TWY E (Echo) and TWY G (Golf) are published as hot spots at Guwahati:
    • They connect the apron and manoeuvring area with access to the main runway.
    • Geometry and intersecting routes make them potential confusion points.
    • NOTAMs and local instructions highlight these locations for extra caution.
  • Local risk drivers at these hot spots:
    • Reduced visibility due to fog, mist and heavy rain.
    • Mixed traffic (civil, training, vehicles) sharing the same intersections.
    • Expectation bias – pilots/vehicles “assuming” the next taxi instruction.
  • Controller actions at TWY E & G:
    • Issue clear, unambiguous taxi and hold-short clearances.
    • Confirm precise readback of taxiway, runway and holding point.
    • Use surveillance and visual scan to verify actual position before runway entry/ crossing.
At Guwahati, if a runway incursion is going to develop on the ground, it is more likely to begin near TWY E or TWY G. Treat these as “red zones” for extra vigilance.

Effective defence against runway incursions is a combination of procedures, discipline and good design.

ATC Best Practices
For controllers:
  • Maintain continuous situational awareness of runway and critical taxiways.
  • Use standard ICAO phraseology; avoid local jargon.
  • Keep clearances and instructions concise; avoid long combined messages.
  • Require complete and correct readbacks for runway/taxi instructions.
  • Cross-check aircraft identity and position before issuing line-up/take-off/landing clearances.
  • In low-visibility conditions, avoid conditional clearances like “line up behind …”.
  • Ensure proper, structured Handover–Takeover including runway status and hot spots.
Use surveillance tools (SMR/ASMGCS) to support, not replace, visual scan.
Pilots, Drivers & Aerodrome Operator
  • Pilots:
    • Read back all runway/taxiway clearances fully and correctly.
    • Stop and query if any doubt exists about routing or holding point.
    • Maintain taxi situational awareness, especially at hot spots.
  • Vehicle Drivers:
    • No movement on manoeuvring area without explicit clearance.
    • RT equipment and training mandatory.
    • Know signs, markings and aerodrome map.
  • Aerodrome Operator:
    • Ensure ICAO-standard markings and lighting are maintained.
    • Clearly chart and publish hot spots.
    • Implement training and access control for vehicle drivers.
Controller discipline = strongest defence
Clear, concise, standard phraseology

Every runway incursion must be reported, investigated and assigned a severity, typically using the ICAO A–E scale.

Severity Classification (A–E)
ICAO severity categories:
  • A – Serious incident: Collision narrowly avoided.
  • B – High risk: Significant potential for collision; requires time-critical evasive action.
  • C – Low risk: Enough time/distance available to avoid collision.
  • D – No immediate safety effect: Incorrect presence on protected area but no direct safety consequence.
  • E – Insufficient information: Data incomplete or conflicting; severity cannot be determined.
Severity is based on proximity, geometry and required reaction, not just “how bad it felt”.
Reporting & Investigation
  • States/ANSPs should have a formal runway-incursion reporting system.
  • Standard forms (initial notification and causal factor forms) support consistent analysis.
  • All runway incursions, including category D and E, should be investigated.
  • Data from many aerodromes is pooled to identify:
    • Common causal patterns,
    • Effective defences,
    • Areas needing additional training or design change.
Risk is a combination of severity and probability. A minor event repeated many times is also a serious warning signal.

Runway incursions are preventable. The strongest defences are clear communication, discipline and shared situational awareness.

Controller Checklist
Before issuing any runway-related clearance, mentally check:
  • Runway is known and confirmed (active, protected areas clear).
  • Traffic – all aircraft and vehicles on/near the runway are accounted for.
  • Hot spots – are there any conflicts near known hot spots?
  • Phraseology – instruction is standard, concise and unambiguous.
  • Readback – will you ensure a full and correct readback?
  • Visibility – in LVP/low visibility, avoid conditional clearances and increase margins.
After a complex sequence, take one second to “rebuild” the runway picture in your mind before the next clearance.
Final Takeaways
  • Runway incursions are usually the result of multiple small failures, not one big mistake.
  • Standard phraseology and correct readbacks remove most communication traps.
  • Hot spots and complex geometry demand extra vigilance, especially at locations like TWY E and TWY G at Guwahati.
  • Every controller, pilot, driver and aerodrome staff member is part of the runway safety net.
  • Consistent reporting and analysis turn incidents into learning and prevention.
You are the last line of defence
Plan – Communicate – Separate
When in doubt: STOP and clarify