In the United States, an average of 1,600 runway incursions occur annually. According to FAA data, general aviation (GA) pilots are responsible for almost half of these events.
Yet, despite the FAA citing runway incursion reduction as one of their top priorities, we have not seen a sustained or substantial reduction in occurrences.
Given the high potential for fatalities from an aircraft incursion onto an active runway, it’s important to understand what constitutes a runway incursion, how they can happen, and what we can do to prevent them.
Key Takeaways
- Definition: Unauthorized presence on active runways or taxiways.
- Types: Operational, pilot, or vehicle/pedestrian deviations.
- Causes: Miscommunication, distractions, and ATC non-compliance.
- Prevention: Stay alert, follow ATC instructions, and know runway markings.
What Is a Runway Incursion?
The Federal Aviation Administration defines runway incursions as:
“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.”
In this definition, the “surface designated for the landing and take-off of aircraft” refers to the movement area, that part of a towered airport under control by air traffic control (ATC), including runways and taxiways.
The FAA categorizes a runway incursion using two measures: type and severity. There are three types of runway incursions:
- Operational Incidents – Occur due to the action of an Air Traffic Controller. Two examples of an operational incident are clearing an aircraft onto a runway when another aircraft is landing or taking off or issuing a take-off clearance while another aircraft or vehicle is occupying the runway.
- Vehicle/Pedestrian Deviations – These are pedestrians or vehicles entering runways or taxiways without ATC authorization. This deviation could be a vehicle crossing a runway hold marking before receiving ATC clearance.
- Pilot Deviations – A pilot’s actions that violate the Federal Aviation Regulation (FAR). Examples include entering an active runway, landing, or taking off without clearance.
The runway incursion severity measure uses five categories that consider an aircraft’s speed, proximity, environmental conditions, evasive action taken, and the available reaction time.
These categories are:
- Accident – an incursion that resulted in a collision
- Category A – A serious incident in which a collision was narrowly avoided
- Category B – An incident in which separation decreases with significant potential for collision, which may require time-critical corrective or evasive action to avoid a collision
- Category C – An incident with ample time or distance to avoid a collision
- Category D – An incident meeting the definition of a runway incursion but with no immediate safety consequences
How Do Runway Incursions Occur?
The most infamous runway incursion occurred on March 27, 1977, when two Boeing 747 aircraft collided at Los Rodeos Airport in Tenerife.
A KLM aircraft was attempting to take off while a Pan Am aircraft was taxiing down the runway, shrouded in fog. All passengers onboard the KLM flight and most Pan Am passengers died, with 583 fatalities and 61 survivors.
The subsequent investigation cited the cause of the accident as the KLM captain’s decision to take off under the mistaken belief that he had received take-off clearance.
While 40-years have passed since that tragedy, it appears we continue to make errors with the potential for similar outcomes.
In 2016, the FAA studied runway incursion data, finding that 66% were classified as pilot deviations. Of these, 50% occurred due to the pilot failing to hold short of a runway, failing to follow ATC instructions, or departing without clearance.
When investigating the contributing factors, almost 62% of the incidents were due to communication errors, and a further 27% to pilot distraction, inattention, or confusion.
The three major areas contributing to runway incursions are a failure to comply with ATC instructions, lack of airport familiarity, and non-conformance with standard operating procedures.
Runway Incursions Rates
In recent years, there has been a decline in runway incursions. Both the FAA and the aviation community have collaborated to eliminate even near-misses.
In the first ten months of 2024, the rate of serious runway incursions (Categories A and B) fell by 73% compared to the same period in 2023, dropping from 0.435 to 0.117 per one million airport operations.
What We Should Focus On
As pilots, we have a duty of continuous learning to ensure currency and competence. Here are some focus areas to prevent runway incursion events.
Taxi Procedures
Towered airports are busy places with considerable distractions. The practice of sterile cockpit procedures is as important when taxiing as when landing or taking off.
All non-essential activities and conversations should cease while maintaining situational awareness outside the aircraft.
Once you have crossed from the apron or ramp onto the movement area of the airport, no movement or action may be taken by you without prior clearance from ATC.
A complete read back is required when a taxi clearance is received, and be sure to write it down or mark it on your airport diagram.
While you cannot move without ATC clearance, it remains your decision as pilot-in-command whether to do so. If you are in doubt or have a concern, you should inform ATC. No penalty accrues to you if you consider you are unable to comply with an instruction safely.
Communication
Know your radio equipment, frequencies, and read back expectations. The opportunity for misunderstanding increases when people are broadcasting on the wrong frequencies, not being concise, using the wrong language, and failing to read back key clearances in their entirety.
If you learned to fly in a small airstrip in the country where “traffic in the vicinity” calls were as busy as it got, take some time to study up and practice before heading to a major hub.
Knowing key phraseology is critical to preventing runway incursions. Hold short, cross, and line-up-and-wait are three important clearances with very specific meaning.
They also require a complete readback to ensure you have heard, understand, and intend to comply.
- “Hold short of the runway at taxiway Bravo” means exactly that. Do not cross the holding position marking with any part of the aircraft until further clearance is received from ATC.
- When cleared to cross a runway, it is only that specific runway you may cross, and you still have a duty to ensure it is safe to comply by using your eyes and ears and keeping your attention out of the cockpit.
- Line up and wait are not instructions for taking off. Line up on the runway and wait until ATC clearance is received. If time passes without clearance, confirm with ATC that you should continue to hold.
Lights, Signage, and Markings
See and be seen is a mantra for flight and also when taxiing. Before you start your engine, the rotating beacon must be on; however, you should also switch on all other lights except your landing light when you begin taxiing.
Be considerate with your strobes if they might adversely affect other aircraft. The landing light should be switched on when crossing a runway and cleared for take-off.
Know your runway holding signage and marking. These are the equivalent of a stop sign on the road. The holding sign is denoted by large white numbers, outlined in black, on a red background.
The holding marking on the ground consists of four yellow lines, two solid and two broken. You’ll encounter the solid lines first when approaching the runway, and you’re required to stop before any part of the aircraft crosses those lines.
You must not cross or pass these marks until ATC clearance is received.
Steps the FAA Has Taken
In a December 2024 brief, it was mentioned that the FAA has worked diligently on implementing new measures to prevent runway close calls. Such as:
- New Surveillance Systems: Surface Awareness Initiative (SAI) systems now enhance situational awareness at nine major airports, with nine more installations planned this year.
- Approach Runway Verification (ARV): Installed at 73 control towers, ARV alerts controllers if an aircraft lines up to land on the wrong surface.
- Runway Incursion Devices (RID): Operational at five airports, RID provides audio/visual alerts when a runway is unavailable.
- Runway Safety Teams: Regular meetings and audits conducted at the 45 busiest U.S. airports.
- Enhanced Training: Modernized simulators improve air traffic controller training efficiency.
- Pilot Alerts: Updated Arrival Alert Notices to reduce wrong surface events.
- Hot Spot Standardization: Unified symbols and terminology for taxiway and runway hazards.
Conclusion
Airport congestion is unlikely to ease any time in the future, with air traffic continuously increasing while new airport approvals face delays due to environmental and social pressures.
We can expect that the threat of runway incursions will remain, requiring us to be on our guard when flying and taxiing.
If in doubt while taxiing, don’t be afraid to ask ATC for progressive taxi instructions. Prevent distractions by using sterile cockpit procedures and maintaining situational awareness.
Above all, remain conversant with signage. If something feels wrong, stop and ask for assistance.
We have a safety obligation to ourselves, our passengers, and our fellow pilots. Let’s stay current on the risks and learn the mitigations to prevent runway incursions.
