Section 1. Runway and Taxiway Safety Areas, Obstacle-Free Zones, and Object-Free Areas


Airport operators must use these safety guidelines when preparing plans and specifications for construction activities in areas that may interfere with aircraft operations. The safety plan should recognize and address these standards for each airport construction project. However, the safety plan must reflect the specific needs of a particular project, and for this reason, these safety guidelines should not be incorporated litrally into project specifications. For additional guidance on meeting safety and security requirements, refer to the planning guide template included in Appendix 2 of this Publication.


A runway safety area is the defined surface surrounding the runway prepared or suitable for reducing the risk of damage to airplanes in the event of an undershoot, overshoot, or excursion from the runway (CARC Publication AN 14-I, Aerodrome Design and Operation). Construction   activities within the standard RSA are subject to the following conditions: 

  1. Runway edges
    1. No construction may occur closer than 200 feet (60m) from the runway centerline  unless the runway is closed or restricted to aircraft operations, requiring an RSA that is  equal to the RSA width available during construction, or 400 feet, whichever is less (see CARC Publication AN 14-I).
    2. Personnel, material, and/or equipment must not penetrate the OFZ, as defined in CARC Publication AN 14-I.
    3. The airport operator must coordinate the construction activity in the RSA as permitted above with the ATCT and issue a local NOTAM.
  2. Runway ends
    1. An RSA must be maintained of such dimensions that it extends beyond the end of the  runway a distance equal to that which existed before construction activity, unless the  runway is closed or restricted to aircraft operations for which the reduced RSA is  adequate (see CARC  Publication AN 14-I). The temporary use of declared distances and/or partial runway closures may help provide the necessary RSA. In addition, all personnel,  materials, and/or equipment must remain clear of the applicable threshold sitting surfaces,  as defined in Appendix 1, “Threshold Sitting Requirements,” of CARC  Publication AN 14-I.
    2. Personnel, material, and/or equipment must not penetrate the OFZ, as defined in CARC Publication AN 14-I.
    3. The safety plan must provide procedures for ensuring adequate distance for blast protection, if required by operational considerations.
    4. The airport operator must coordinate construction activity in this portion of the RSA with the ATCT and issue a local NOTAM.
  3. Excavations
    1. Constructions contractors must prominently mark open trenches and excavations at the construction site with red or orange flags, as approved by the airport operator, and light them with red lights during hours of restricted visibility or darkness.
    2. Open trenches or excavations are not permitted within 200 feet (60m) of the runway centerline and at least the existing RSA distance from the runway threshold while the runway is open. If the runway must be opened before excavations are backfilled, cover the excavations appropriately. Coverings for open trenches or excavations must be of sufficient strength to support the weight of the heaviest aircraft operating on the runway.


  1. Unrestricted construction activity is permissible adjacent to taxiways when the taxiway is restricted to aircraft such that the available taxiway safety area is equal to at least ½ of the widest wingspan of the  aircraft expected to use the taxiway and the available taxiway object-free area is equal to  at least 7 times the widest wingspan plus 10 feet. (See CARC Publication AN 14-I for guidance on taxiway safety and object-free areas.) Construction activity may be accomplished closer to a taxiway, subject to the following restrictions:
    1. The activity is first coordinated with the airport operator.
    2. Appropriate NOTAMs are issued.
    3. Marking and lighting meeting the provisions of paragraph 3-9 are implemented.
    4. Adequate clearance is maintained between equipment and materials and any part of an aircraft. If such clearance can only be maintained if an aircraft does not have full use of the entire taxiway width (with its main landing gear at the edge of the pavement), then it will be necessary to move personnel and equipment for each passing aircraft. In these situations, flag persons will be used to direct construction equipment, and wing walkers may be necessary to guide aircraft. Wing walkers should be airline/aviation personnel   rather than construction workers.
  2. Construction contractors must prominently mark open trenches and excavations at the construction site, as approved by the airport operator, and light them with red lights during hours of restricted visibility or darkness
  3. Excavations and open trenches may be permitted up to the edge of a structural taxiway and apron pavement provided the drop-off is marked and lighted per paragraph 3-9, “Hazard Marking and Lighting.”

Section 2. Temporary Runway Thresholds


Construction activity in a runway approach area may result in the need to partially close a  runway or displace the existing runway threshold. In either case, locate the threshold in  accordance with CARC  Publication AN 14-I. Objects that do not penetrate these surfaces may still be obstructions to air navigation and may affect  standard instrument approach procedures. Coordinate these objects with the CARC appropriate party Office, as necessary. Refer to  the current edition of CARC Publication An 14-I for guidance on threshold sitting requirements. The  partial runway closure, the displacement of the runway threshold, as well as closures of  the complete runway and other portions of the movement area also requires coordination  with appropriate ATCT personnel and airport users. Caution regarding partial runway closures: When filing a NOTAM for a partial runway closure, clearly state to FSS personnel that the portion of pavement located prior to the threshold is not available for landing and departing traffic. In this case, the threshold has been moved for both landing and takeoff purposes (this is different than a displaced threshold). Example NOTAM:  “North 1,000 feet of Runway 18/36 is closed; 7,000 feet remain available on Runway 18 and Runway 36 for arrivals and departures.” There may be situations where the portion of closed runway is available for taxiing only. If so, the NOTAM must reflect this condition. Caution regarding displaced thresholds:  Implementation of a displaced threshold affects runway length available for aircraft landing over the displacement. Depending on the reason for the displacement (to provide obstruction clearance or RSA), such a displacement may also require an adjustment in the landing distance available and accelerate-stop distance available in the opposite direction.  If project scope includes personnel, equipment, excavation, etc. within the RSA of any usable runway end, we do not recommend a displaced threshold unless arrivals and departures toward the construction activity are prohibited. Instead, implement a partial closure.


Ensure that markings for temporary displaced thresholds are clearly visible to pilots approaching the airport to land. When construction personnel and equipment are located  close to any threshold, a temporary visual NAVAID, such as runway end identifier lights  (REIL), may be required (even on unlighted runways) to define the new beginning of the  runway clearly. A visual vertical guidance device, such as a visual approach slope indicator (VASI), pulse light approach slope indicator (PLASI), or precision approach path indicator (PAPI), may be necessary to assure landing clearance over personnel, vehicles, equipment, and/or above-grade stockpiled materials. If such devices are installed, ensure an appropriate descriptive NOTAM is issued to inform pilots of these conditions. The current edition of CARC Publication AN 14-I, describes standard marking colors and layouts. In addition, we recommend that a temporary runway threshold be marked using the following guidelines:

  1. Airport markings must be clearly visible to pilots; not misleading, confusing, or deceptive; secured in place to prevent movement by prop wash, jet blast, wing vortices, or other wind currents; and constructed of materials that would minimize damage to an aircraft in the event of inadvertent contact.
    1. Pavement markings for temporary closed portions of the runway should consist of yellow chevrons to identify pavement areas that are unsuitable for takeoff/landing (see  CARC Publication An 14-I). If unable to paint the markings on the pavement, construct them from any of the following materials: double-layered painted snow fence, colored plastic, painted sheets of plywood, or similar materials. They must be properly configured and secured to prevent movement by prop wash, jet blast, or other wind currents.
    2. It may be necessary to remove or cover runway markings, such as runway designation markings and aiming point markings, depending on the length of construction and type of activity at the airport.
    3. When threshold markings are needed to identify the temporary beginning of the runway that is available for landing, use a white threshold bar of the dimensions specified in CARC  Publication AN 14-I.
    4. If temporary outboard elevated or flush threshold bars are used, locate them outside of the runway pavement surface, one on each side of the runway. They should be at least 10 feet (3m) in width and extend outboard from each side of the runway so they are clearly visible to landing and departing aircraft. These threshold bars are white. If the white threshold bars are not discernable on grass or snow, apply a black background with appropriate material over the ground to ensure the markings are clearly visible.
    5. A temporary threshold may also be marked with the use of retro reflective, elevated markers. One side of such markers is green to denote the approach end of the runway; the side that is seen by pilots on rollout is red.
    6. At JCAR part 139 certificated airports, temporary elevated threshold markers must  be mounted with a frangible fitting (see JCAR part 139.309).However, at  Non-certificated airports, the temporary elevated threshold markings may either be mounted with a frangible fitting or be flexible.
  2. The application rate of the paint to mark a short-term temporary runway threshold may deviate from the standard, but the dimensions must meet the existing standards, unless coordinated with the appropriate offices.
  3. When a runway is partially closed, the distance remaining signs for aircraft landing in the opposite direction should be covered or removed during the construction.


A temporary runway threshold must be lighted if the runway is lighted and it is the intended threshold for night landings or instrument meteorological conditions. We recommend that temporary threshold lights and related visual NAVAIDs be installed outboard of the edges of the full-strength pavement with bases at grade level or as low as possible, but not to exceed 3 inches (7.6cm) above ground. When any portion of a base is  above grade, place properly compacted fill around the base to minimize the rate of  gradient change so aircraft can, in an emergency, cross at normal landing or takeoff  speeds without incurring significant damage. We recommend that the following be observed when using temporary runway threshold lighting:

  1. Maintain threshold and edge lighting color and spacing standards as described in CARC Publication An 14-I.
  2. When the runway has been partially closed, disconnect edge and threshold lights with associated isolation transformers on that part of the runway at and behind the threshold (i.e., the portion of the runway that is closed). Alternately, cover the light fixture in such a way as to prevent light leakage. Avoid removing the lamp from energized fixtures because an excessive number of isolation transformers with open secondary´s may damage the regulators and/or increase the current above its normal value.
  3. Secure, identify, and place any temporary exposed wiring in conduit to prevent electrocution and fire ignition sources.
  4. Reconfigure yellow lenses (caution zone), as necessary. If the runway has centerline lights, reconfigure the red lenses, as necessary, or place the centerline lights out of service.
  5. Relocate the visual glide slope indicator (VGSI), such as VASI and PAPI; other airport lights, such as REIL; and approach lights to identify the temporary threshold. Another option is to disable the VGSI or any equipment that would give misleading indications to pilots as to the new threshold location. Installation of temporary visual aids may be necessary to provide adequate guidance to pilots on approach to the affected runway, coordinate its installation or disabling with Airway Facilities Systems Management Office.
  6. Issue a NOTAM to inform pilots of temporary lighting conditions.

Section 3. Other Construction Marking and Lighting Activities


Ensure that construction areas, including closed runways, are clearly and visibly  separated from movement areas and that hazards, facilities, cables, and power lines are identified prominently for construction contractors. Throughout the duration of the  construction project, verify that these areas remain clearly marked and visible at all times  and that marking and lighting aids remain in place and operational. Routine inspections  must be made of temporary construction lighting, especially battery powered lighting  since weather conditions can limit battery life.

 3-8 . Closed Runway and Taxiway Marking and Lighting.

Closed runway markings consist of a yellow “X” in compliance with the standards of CARC Publication An 14-I. A very effective and preferable visual aid to depict temporary closure is the lighted “X” signal placed on or near the runway designation numbers. This device is much more discernible to approaching aircraft than the other materials described. If the lighted “X” is not available, construct the marking of any of the following materials: double-layered painted snow fence, colored plastic, painted sheets of plywood, or similar materials. They must be properly configured and secured to prevent movement by prop wash, jet blast, or other wind currents. In addition, the airport operator may install barricades, traffic cones, activate stop bars, or other  acceptable visual devices at major entrances to the runways to prevent aircraft from  entering a closed portion of runway. The placement of even a single reflective barricade with a “do not enter” sign on a taxiway centerline can prevent an aircraft from continuing onto a closed runway. If the taxiway must remain open for aircraft crossings, barricades or markings, as described above or in paragraph 3-9, should be placed on the runway.

  1. Permanently closed runways.
    For runways and taxiways that have been permanently closed, disconnect the lighting circuits. For runways, obliterate the threshold marking, runway designation marking, and touchdown zone markings, and place “X’s” at each end and at 1,000-foot (300-m) intervals. For taxiways, place an “X” at the entrance of the closed taxiway. 
  2. Temporarily closed runway and taxiways.
    For runways that have been temporarily closed, place an “X” at the each end of the runway. With taxiways, place an “X” at the entrance of the closed taxiway.
  3. Temporarily closed airport.
    When the airport is closed temporarily, mark the runways as closed and turn off the airport beacon.
  4. Permanently closed airports
    When the airport is closed permanently, mark the runways as permanently closed, disconnect the airport beacon, and place an “X” in the segmented circle or at a central location if no segmented circle exists.


Provide prominent, comprehensible warning indicators for any area affected by construction that is normally accessible to aircraft, personnel, or vehicles. Using appropriate hazard marking and lighting may prevent damage, injury, traffic delays, and/or facility closures. Hazard marking and lighting must restrict access and make specific hazards obvious to pilots, vehicle drivers, and other personnel. Barricades, traffic cones (weighted or sturdily attached to the surface), or flashers are acceptable methods used to identify and define the limits of construction and hazardous areas on airports. Provide temporary hazard marking and lighting to prevent aircraft from taxiing onto a closed runway for takeoff and to identify open manholes, small areas under repair, stockpiled material, and waste areas. Also consider less obvious construction-related hazards and include markings to identify CARC, airport, cables and power lines; instrument landing system (ILS) critical areas; airport surfaces, such as RSA, OFA, and OFZ; and other sensitive areas to make it easier for contractor personnel to avoid these areas. The construction specifications must include a provision requiring the contractor to have a person on call 24 hours a day for emergency maintenance of airport hazard lighting and barricades. The contractor must file the contact person’s information with the airport.

  1. Non-movement areas.
    Indicate construction locations on non-movement areas in which no part of an aircraft may enter by using barricades that are marked with diagonal, alternating orange and white stripes. Barricades may be supplemented with alternating orange and white flags at least 20 by 20 inches (50 by 50 cm) square and made and installed so they are always in an extended position, properly oriented, and securely fastened to eliminate jet engine ingestion. Such barricades may be many different shapes and made from various materials, including railroad ties, sawhorses, jersey barriers, or barrels. During reduced visibility or night hours, supplement the barricades with red lights, either flashing or steady-burning, which should meet the luminance requirements (Ministry of public works). The intensity of the lights and spacing for barricade flags and lights must adequately and without ambiguity delineate the hazardous area.
  2.  Movement areas.
    Use orange traffic cones; red lights, either flashing or steady-burning, which should meet  the luminance requirements of the(Ministry of public works);  collapsible barricades marked with diagonal,  alternating orange and white stripes; and/or signs to separate all construction/maintenance  areas from the movement area. All barricades, temporary markers, and other objects placed and left in safety areas associated with any open runway, taxiway, or taxilane must be as low as possible to the ground; of low mass; easily collapsible upon contact with an aircraft or any of its components; and weighted or sturdily attached to the surface to prevent displacement from prop wash, jet blast, wing vortex, or other surface wind currents. If affixed to the surface, they must be frangible at grade level or as low as possible, but not to exceed 3 inches (7.6cm) above the ground. Do not use non-frangible hazard markings, such as concrete barriers and/or metal-drum-type barricades, in aircraft movement areas. Do not use railroad ties on runways. Use highly reflective barriers with flashing or steady burning red lights to barricade taxiways leading to closed runways.  Evaluate all operating factors when determining how to mark temporary closures that can   last from 10 to 15 minutes to a much longer period of time. However, we strongly recommend that, even for closures of relatively short duration, major taxiway/runway intersections be identified with barricades spaced no greater than 20 feet (6m) apart.  Mark the barricades with a flashing or steady-burning red light. At a minimum, use a single barricade placed on the taxiway centerline.

Construction activities, materials/equipment storage, and vehicle parking near electronic NAVAIDs require special consideration since they may interfere with signals essential to air navigation. Evaluate the effect of construction activity and the required distance and direction from the NAVAID for each construction project. Pay particular attention to stockpiling material, as well as to movement and parking of equipment that may interfere   with line of sight from the ATCT or with electronic emissions. Interference from construction may require NAVAID shutdown or adjustment of instrument approach minimums for IFR. This condition requires that a NOTAM be filed. Construction activities and materials/equipment storage near a NAVAID may also obstruct access to the equipment and instruments for maintenance. Before commencing construction activity, parking vehicles, or storing construction equipment and materials near a NAVAID, consult with the nearest CARC Airway Facilities Office.

 3-11 . Construction Site Access and Haul Roads

Determine the construction contractor’s access to the construction sites and haul roads.  Do not permit the construction contractor to use any access or haul roads other than those approved. Construction contractors must submit specific proposed routes associated with construction activities to the airport operator for evaluation and approval as part of the safety plan before beginning construction activities. These proposed routes must also provide specifications to prevent inadvertent entry to movement areas. Pay special attention to ensure that ARFF right of way on access and haul roads is not impeded at any time and that construction traffic on haul roads does not interfere with NAVAIDs or  approach surfaces of operational runways


Stockpiled materials and equipment storage are not permitted within the RSA and OFZ of  an operational runway. The airport operator must ensure that stockpiled materials and equipment adjacent to these areas are prominently marked and lighted during hours of restricted visibility or darkness. This includes determining and verifying that materials re stored at an approved location to prevent foreign object damage and attraction of wildlife.


Contractors may not use open-flame welding or torches unless adequate fire safety precautions are provided and the airport operator has approved their use. Under no circumstances should flare pots be used within the AOA at any time. The use of electrical blasting caps must not be permitted on or within 1,000 feet (300m) of the airport property.

3-14 . Foreign Object Debris (FOD) Management.

Waste and loose materials, commonly referred to as FOD, are capable of causing damage to aircraft landing gears, propellers, and jet engines. Construction contractors must not leave or place FOD on or near active aircraft movement areas. Materials tracked onto these areas must be continuously removed during the construction project. We also recommend that airport operators and construction contractors carefully control and continuously remove waste or loose materials that might attract wildlife.

Section 4. Safety Hazards and Impacts

 3-15 . Overview.

The situations identified below are potentially hazardous conditions that may occur  during airport construction projects. Safety area encroachments, unauthorized and improper ground vehicle operations, and unmarked or uncovered holes and trenches near aircraft operating surfaces pose the most prevalent threats to airport operational safety during airport construction projects. Airport operators and contractors should consider the Following when performing inspections of construction activity:

  1. Excavation adjacent to runways, taxiways, and aprons.
  2. Mounds of earth, construction materials, temporary structures, and other obstacles near  any open runway, taxiway, or taxilane; in the related object-free area and aircraft approach or departure areas/zones; or obstructing any sign or marking.
  3. Runway resurfacing projects resulting in lips exceeding 3 inches (7.6cm) from pavement edges and ends.
  4. Heavy equipment (stationary or mobile) operating or idle near AOAs, in runway approaches and departures areas, or in OFZs.
  5. Equipment or material near NAVAIDs that may degrade or impair radiated signals and/or the monitoring of navigational and visual aids. Unauthorized or improper vehicle operations in localizer or glide slope critical areas, resulting in electronic interference and/or facility shutdown.
  6. Tall and especially relatively low-visibility units (i.e., equipment with slim profiles)— cranes, drills, and similar objects—located in critical areas, such as OFZs and approach zones.
  7. Improperly positioned or malfunctioning lights or unlighted airport hazards, such as holes or excavations, on any apron, open taxiway, or open taxilane or in a related safety, approach, or departure area.
  8. Obstacles, loose pavement, trash, and other debris on or near AOAs. Construction debris (gravel, sand, mud, paving materials, etc.) on airport pavements may result in aircraft propeller, turbine engine, or tire damage. Also, loose materials may blow about, potentially causing personal injury or equipment damage.
  9. Inappropriate or poorly maintained fencing during construction intended to deter human and animal intrusions into the AOA. Fencing and other markings that are inadequate to separate construction areas from open AOAs create aviation hazards.
  10. Improper or inadequate marking or lighting of runways (especially thresholds that have been displaced or runways that have been closed) and taxiways that could cause pilot confusion and provide a potential for a runway incursion. Inadequate or improper methods of marking, barricading, and lighting of temporarily closed portions of AOAs create aviation hazards.
  11. Wildlife attractants—such as trash (food scraps not collected from construction personnel activity), grass seeds, or ponded water—on or near airports.
  12. Obliterated or faded markings on active operational areas.
  13. Misleading or malfunctioning obstruction lights. Unlighted or unmarked obstructions in the approach to any open runway pose aviation hazards.
  14. Failures to issue, update, or cancel NOTAMs about airport or runway closures or other construction-related airport conditions.
  15. Failure to mark and identify utilities or power cables. Damage to utilities and power  cables during construction activity can result in the loss of runway/taxiway lighting; loss  of navigational, visual, or approach aids; disruption of weather reporting services; and/or  loss of communications.
  16. Restrictions on ARFF access from fire stations to the runway-taxiway system or airport buildings.
  17. Lack of radio communications with construction vehicles in airport movement areas.
  18. Objects, regardless of whether they are marked or flagged, or activities anywhere on or near an airport that could be distracting, confusing, or alarming to pilots during aircraft operations.
  19. Water, snow, dirt, debris, or other contaminants that temporarily obscure or derogate the visibility of runway/taxiway marking, lighting, and pavement edges. Any condition or factor that obscures or diminishes the visibility of areas under construction.
  20. Spillage from vehicles (gasoline, diesel fuel, oil, etc.) on active pavement areas, such as runways, taxiways, ramps, and airport roadways.
  21. Failure to maintain drainage system integrity during construction (e.g., no temporary drainage provided when working on a drainage system).
  22. Failure to provide for proper electrical lockout and tagging procedures. At larger airports with multiple maintenance shifts/workers, construction contractors should make provisions for coordinating work on circuits.
  23. Failure to control dust. Consider limiting the amount of area from which the contractor is allowed to strip turf.
  24. Exposed wiring that creates an electrocution or fire ignition hazard. Identify and secure wiring, and place it in conduit or bury it.
  25. Site burning, which can cause possible obscuration.
  26. Construction work taking place outside of designated work areas and out of phase.