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    It was Bob Dylan who first sang "The AC's Are A'Changin'"... or maybe I just couldn't understand him.

    Either way, many of the FAA Advisory Circulars (AC) are indeed changing. But here at Sightline, the most important (with respect to airport pavement markings) are AC 150/5370-10 and AC 150/5340-1. Here are the highlights:

Draft AC 150/5370-10G, Standards for Specifying Construction of Airports

• Status: Draft Series
• Effective Date: The AC is currently available for Industry Comment (Deadline 10/31/2013)
• Result: Once published, it will cancel the previous AC 150/5370-10F
• What Changed: Item P-620 "Runway and Taxiway Painting" has been edited to include:
  1. "620-2.3 Reflective media" - Suggested initial reflectivity readings of markings at installation dependent upon glass bead type.
  2. "620-3.3 Preparation of surface" - Elaborated upon previous definition and methods of surface preparation. Degrees of paint removal are suggested to be defined by the engineer.
  3. "620-3.4 Layout of markings" - Glass beads are now required to be applied on non-movement area boundary markings.
  4. "620-3.5 Application" - Contractor submittals required certifying proper surface conditions, equipment, environment, etc., prior to application.
  5. NEW "620-3.6 Test strips" - A test strip of paint and glass beads must be performed to establish line quality prior to application. Application Rates for Paint and Glass Beads now include a specific coverage for waterborne/solvent paints when using Type IV glass beads.
  6. "Testing Requirements" - ASTM 2302 provides a method to quantify reflectivity of pavement markings.
• Our Take: The FAA has incorporated several best practices borrowed from the pages of the Airfield Marking Handbook. Nearly all of the changes increase quality control measures for new construction. Until these measures are included in the 5340-1, we encourage those maintaining existing markings to follow this guidance and other best practices. If you would like to submit comments relating to markings, feel free to email them to me and I will incorporate them into our comments.

AC 150/5340-1L, Standards for Airport Markings

• Status: Published
• Effective Date: 09/27/2013
• Result: Canceled the previous AC 150/5340-1K
• What Changed: "Standards for Airport Markings" has been edited to include:
  1. "1.3 Surface marking practices" - Subpart f. Removal of Markings - now includes new language, "The physical removal of any old marking(s) must include a pre-determined larger size and shape of a removal area that encompasses the old marking(s) and by grouping adjacent markings together into a larger rectangular removal area. The rationale behind this practice is to eliminate the continued visual appearance of the removed marking(s)."
  2. "1.4 Requirements and recommendations..." - Additional markings are now required to have black borders and/or glass beads. Table 1-2 on page 10 enumerates all marking types and whether the enhancements to conspicuity are required or recommended.
  3. "4.4 Taxiway edge marking" - Subpart a. Purposes - re-emphasizes dashed taxiway edge markings must now be continuous, or solid double yellow, at the entrances of runways. This standard includes no taxi islands delineated with double dashed edge markings.
  4. Taxiway Edge Marking Interruption - Taxiway edge markings shall be interrupted when intersected by Pattern A, B, and C holding position markings. The same rule applies for non-movement area boundary markings. The edge markings will abut the six-inch black border on both sides of all of these markings. In the case these markings are not bordered in black, the taxiway edge markings stop six inches from the intersecting holdbars/markings.
• Our Take: The concept of performing paint removal operations in a large area to encompass groups of markings is tricky. My initial thoughts are this strategy will work beautifully in instances of waterblasting on concrete - you'll essentially be "cleaning" the surrounding pavements to match the color of the newly exposed (and coincidentally clean) pavements - which will reduce contrast and the chances the removal area will "mimic" markings. However, consider asphalt surfaces, prevalent in the industry. If it's more than two years old (when black borders become required for markings on asphalt), the pavement surrounding the markings will be faded from UV and oxidation. When markings are removed, darker pavement will be exposed having been preserved by the marking. I have reservations about including a "larger size and shape of a removal area" in the effort to make the entire area look the same. I imagine it could significantly increase the cost of paint removal in those instances. Be sure to have the operator provide test strips of sample removal, and come to a mutual agreement on expectations and resulting product.

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