No, there are no criteria to determine when markings require maintenance/repainting. Several elements exist:
But some are missing:
- A measurement method. Research topic of AR-TN03/22 (2003).
- Criteria for marking compliance. Were proposed in the research project.
The result is current checks for conspicuity are subjective, and there is, as far as I know and as surprising as it is, no predefined criteria to evaluate the need for maintenance. The research project conducted by FAA doesn't seem to have any regulatory implementation.
This project based evaluation on three criteria:
- Retro-reflectivity threshold, depending on color.
- Tolerance for tint change.
- Paint coverage
No formal criteria for Part 139 commercial aviation, the most regulated, means no formal criteria exist for any type of airport in the US.
Section 311 of Part 139, Marking, signs, and lighting, certainly requires markings to be "properly maintained" according to FAA "methods and procedures":
Each certificate holder must provide and maintain marking systems for air carrier operations on the airport that are authorized by the Administrator and consist of at least the following:
(1) Runway markings meeting the specifications for takeoff and landing minimums for each runway.
(2) A taxiway centerline.
(3) Taxiway edge markings, as appropriate.
(4) Holding position markings.
(5) Instrument landing system (ILS) critical area markings.
Each certificate holder must properly maintain each marking, sign, or lighting system installed and operated on the airport. As used in this section, to “properly maintain” includes cleaning, replacing, or repairing any faded, missing, or nonfunctional item; keeping each item unobscured and clearly visible; and ensuring that each item provides an accurate reference to the user.
FAA Advisory Circulars contain methods and procedures for the equipment, material, installation, and maintenance of marking, sign, and lighting systems listed in this section that are acceptable to the Administrator.
And also required related maintenance procedures to be described in the certification manual reviewed by FAA before granting its certificate:
A description of, and procedures for maintaining, the marking, signs, and lighting systems, as required under §139.311
FAA airport certification
FAA certifies airport according to Airport Compliance Manual — Order 5190.6. Its chapter 7, Airport Operations, determines responsibilities for the airport "sponsor" as related to maintenance for any certificated airport.
Part 139 airports will have additional constraints, not listed here:
[...] This chapter does not cover the additional requirements that Title 14 Code of Federal Regulations (CFR) Part 139, Certification of Airports, imposes on airports serving certificated scheduled air carriers. (Contact the FAA Airport Safety and Operations Division, AAS-300, in Washington DC, for additional information on Part 139 compliance matters.)
These sponsor responsibilities include runway inspection and repairs, included repainting markings:
7.2. Scope of Airport Maintenance Federal Obligations.
b. Airport Facilities to be Maintained.
[...] airport sponsors are required to inspect runways, taxiways, and other common-use paved areas at regular intervals to ensure compliance with operational and maintenance standards. Sponsors must make routine repairs, such as filling, sealing cracks, and repainting markings (as shown here) to prevent progressive pavement deterioration.
The actual way markings maintenance is conducted will be reviewed during the certification process. FAA provides guidelines in AC 150/5380-7A, Airport Pavement Management Program:
7.4. Maintenance Procedures.
Generally, airport agreements require the sponsor to carry out a continuing program of preventive and remedial maintenance. The maintenance program is intended to ensure that the airport facilities are at all times in good and serviceable condition to use in the way they were designed.
Advisory Circular (AC) 150/5380-7A, Airport Pavement Management Program, discusses the Airport Pavement Management System (APMS) concept, its essential components, and how it can be used to make cost-effective decisions about pavement maintenance and rehabilitation.
Self-inspections in part of the pavement management process are described in their own document.
Runway inspection, by airport owner/operator must comply with AC 150/5200-18, which references the marking specifications found in AC 150/5340-1 and states this standard is mandatory for Part 139, and when construction or rehabilitation is paid by federal funds:
Airport markings provide important information to pilots during takeoff, landing, and taxiing. To avoid confusion and disorientation, airport markings should be in compliance with FAA marking standards specified in AC 150/5340-1, Standards for Airport Markings. (Compliance with these standards is mandatory for operators of airports certificated under Part 139 and for airport operators that have accepted Federal funds for runway and taxiway construction/rehabilitation.)
Elements that "should" be taken into account during the inspection:
During the marking inspection, the inspector should:
(1) Check markings for correct color-coding, peeling, blistering, chipping, fading, and obscurity due to rubber buildup.
(2) Check to see if all runway hold position markings are clearly visible.
(3) During and after construction projects, check new markings for compliance with FAA marking standards.
(4) If the markings have glass beads, check markings during periods of darkness to determine if the reflectivity of glass beads is adequate at night.
(5) Report and monitor any nonstandard marking or markings that are obscured, faded or
New marking measurements
There is no value indicated for marking visibility (conspicuity), but there are minimum values for different parameters given in AC 150/5370-10, Airport Construction Standards, at Item P-620 Runway and Taxiway Marking. They are used to evaluate the quality of the painting done by a contractor.
These criteria are numerous, due to the multiplicity of materials which can be used:
- Waterborne, epoxy, methacrylate, solvent-base and preformed thermoplastic.
- Inclusion of glass beads or not.
- For waterborne or solvent based paints, different types (Federal Specification TT-P-1952F, types I, II, III) are used for different purposes.
- Daylight directional reflectance (relative to magnesium oxide, according to ASTM E2302) for epoxy paint: White: not less than 75% , Yellow: not less than 55%.
- Retro-Reflectance for thermoplastic (mcd/m²/lux ASTM E1710): White 225, Yellow 100, Red 35.
Research by FAA
The FAA report for Development of Methods for Determining Airport Pavement Marking Effectiveness was released in 2003. From the abstract:
Presently, the conspicuity is determined by visual inspections of segments of these markings, but the validity of these inspections cannot always be confirmed.
This study was undertaken to develop a method for a quick and accurate evaluation of paint markings. A manual method was required for eliminating subjectivity in the current method, and an automated method was developed for evaluation of larger surface markings over a vast airport area. In addition, the study also established a threshold pass/fail limit for white and yellow paint.
It was found that for the manual method, three devices are required: (1) a retro-reflectometer is required for determining retro-reflectivity of the beads, (2) a spectrophotometer is required to determine whether or not the paint marking has faded out of tolerance, and (3) a transparent grid is used to determine coverage of the paint. If any one of these three tests fails, the pavement marking fails.
For the automated method, a van-mounted Laserlux or similar mobile unit is required. The automated method increases the speed and sample size. It works well for large airports, which have very long runway centerlines and threshold markings.
The retro-reflective threshold limit for yellow paint is 70 mcd/m²/lx and for white paint 100 mcd/m²/lx. The coverage threshold pass/fail limit is 50%.
FAA indeed follows ICAO recommendations which are stated in Annex 14:
10.5.2 A system of preventive maintenance of visual aids shall be employed to ensure lighting and marking system reliability.
Note.— Guidance on preventive maintenance of visual aids is given in the Airport Services Manual (Doc 9137), Part 9.
2.8.1 All markings on paved areas should be inspected at least semi-annually. Local conditions will determine when to inspect. In general, a spring and fall inspection will suffice to detect deterioration due to the winter and summer weather extremes.
2.8.2 Markings which are faded or discoloured by soil should be repainted. When rubber deposits have been removed from the pavement all defaced markings should be restored as soon as possible.
The main technical document for runways markings is IPRF 01-G-002-05-1, Airfield Marking Handbook. ICAO seems to use it as the reference for evaluating markings (example for Latin-America):
Faded colors or appearance.
Poor nighttime visibility or retro-reflectivity.
Existing markings are worn 50 percent or more.
Existing markings are covered with contaminants.
Markings are not representing properly its meaning anymore
Positions and dimension of existing markings (tolerances).