Runway Incursion and Runway Excursion

Runway Incursion and Runway Excursion

Runway events are among the most critical safety issues in civil aviation. ICAO and EASA prioritise prevention through multiple programmes.

Definitions

Runway incursion

Definition (ICAO Doc 9870): any unauthorised presence of an aircraft, vehicle or person on the protected area of a runway — the movement area intended for take-off, landing and safety margins.

Severity categories:

• Category A — near-collision, last-moment avoidance.
• Category B — significant collision potential.
• Category C — adequate time/distance to react.
• Category D — no immediate safety consequence.

Typical causes:

• Pilot taxis onto wrong / active runway,
• Pilot misses hold-position marking,
• Pilot misunderstands ATC instruction,
• Driver of an airport vehicle crosses hold point,
• Pilot crosses active runway without clearance.

Famous examples:

• Tenerife 1977 (Pan Am / KLM, 583 fatalities) — KLM 747 took off while Pan Am 747 was on the runway. Still the deadliest aviation accident.
• Linate 2001 (SAS / Cessna Citation, 118 fatalities) — Citation taxied onto active runway in fog.

Runway excursion

Definition: an aircraft leaves the runway laterally or off the end — during take-off or landing.

Types:

• Lateral excursion — lateral deviation from the runway.
• Overrun — overshoot past the runway end.

Frequency: at ~1/3 of all accidents, runway excursion is the most frequent accident category in GA.

Typical causes:

• Unstable approach (too fast, too high),
• Hydroplaning on wet/contaminated runway,
• Crosswind underestimated or technique flawed,
• Brake failure,
• Aerodynamic stall in the runway area,
• Loss of control with ground wind change,
• Wrong flap setting.

Aerodrome protective measures

Hold-position markings

Appearance: yellow double line with dashed line on the taxiway before the runway:

• Four yellow lines (2 solid + 2 dashed) parallel to the runway.
• Marks the point beyond which an aircraft must not taxi without ATC clearance.

Impact:

• At controlled aerodromes: obtain "cleared to cross runway" or "hold short of runway" from the tower.
• At uncontrolled aerodromes: secure your crossing yourself (visual check, radio call on aerodrome frequency).

Runway markings and lighting

• Runway threshold markings (see lesson Aerodrome markings (memorise) in Subject 010).
• Runway identification (number + L/C/R).
• Anti-collision light at the runway end on some modern aerodromes.
• Stopbar lights (red lights across the taxiway) at international airports — never cross while lit.

A-SMGCS (Advanced Surface Movement Guidance and Control)

• Modern system at larger airports (Frankfurt, Munich) — includes ground radar and anti-conflict systems.
• For PPL more of background knowledge.

Pilot prevention strategies

1. Awareness before every runway

• STOP, look left and right, listen on the radio,
• Sterile cockpit during taxi — no distractions,
• When in doubt: ask ATC.

2. Clear radio communication

• Use standard phraseology,
• Read-back every hold/cross instruction,
• On misunderstanding: "Say again".

3. Active-runway awareness

• Listen to ATIS and note runway in use,
• Plan the taxi route in advance on the chart.

4. In low visibility

• In fog/night: extreme care while taxiing,
• Some aerodromes use LVP (Low Visibility Procedures) with extra restrictions,
• If lost: stop and ask ATC — don't "guess and try".

5. On approach (against excursion)

• Stabilised Approach Criteria:
  • Speed ±10 kt of target,
  • Sink rate < 1 000 fpm,
  • Final configuration change < 500 ft AGL,
  • On centreline and glide path.
• If unstable: go-around — always an option!

6. On landing

• Touchdown in the first third of the runway,
• If not achieved: go-around rather than land too late.

7. On wet/contaminated runway

• Calculate reduced braking (see Contaminated Runways),
• Prioritise aerodynamic braking (flaps up, elevator pulled).
• On hydroplaning: do not brake hard; brake lightly and evenly.

EASA and ICAO measures

ICAO:

• Doc 9870 — Manual on the Prevention of Runway Incursions.
• Doc 9981 — PANS-Aerodromes.
• Mandatory Runway Safety Teams at commercial airports.

EASA:

• SIB 2023-04 (Runway Excursion).
• EASA Action Plan for Runway Safety.

Germany:

• DFS and LBA run runway-safety programmes.
• NfL with notices for specific aerodromes.