FAA AC 150/5370-10 Grade Requirements

FAA Advisory Circular 150/5370-10 (Standards for Specifying Construction of Airports) is the FAA's standard specification for AIP-funded airport construction projects. When a project receives Airport Improvement Program funding, the airport sponsor and contractors are required to follow AC 150/5370-10 specifications — including the grade verification and documentation requirements in Section 80 (Earthwork).

This is not optional guidance. It is a contractual requirement tied to AIP funding. FAA program managers verify compliance during oversight visits, and documented non-compliance can trigger stop-work orders, AIP funding reviews, and contractor debarment proceedings for severe or repeated violations.

The specification is available directly from the FAA Airports website. The current version supersedes prior editions — always verify you are working from the version cited in your specific contract documents, as airport sponsors sometimes cite earlier editions.

Section 80 of AC 150/5370-10 specifies grade tolerance by pavement area type. The tolerances are tighter for taxiways than runways because taxiway surface drainage precision is more critical — aircraft wheel loads are more concentrated and surface ponding risks are higher.

"Per station" in the tolerance specification means at each measured point — typically every 50 feet along the centerline and offset lines across the pavement width. A runway that is 150 feet wide requires measurements at the centerline plus at least two offset points per 50-foot station, producing three grade shots every 50 feet.

A deviation that exceeds tolerance at a single measurement point is a non-conformance. It does not matter that adjacent points are within tolerance. The non-conforming point must be documented, the grade corrected, and a post-correction measurement logged before the inspector can sign off on the lift.

One of the most operationally significant requirements in AC 150/5370-10 is that the airport inspector (the owner's representative or resident project representative) must sign off on each earthwork lift before the next lift can be placed. This creates a mandatory inspection hold point at each lift elevation.

In practice, this means:

• Grade documentation for the completed lift must be compiled and presented to the inspector
• The inspector reviews the documentation for completeness and compliance
• Any non-conforming points must be resolved and re-documented before the inspector signs off
• Only after written sign-off (typically in the daily inspection report) can the contractor begin the next lift
• Placing material on an unsigned lift is a contract violation — the entire layer may need to be removed and the process restarted

Contractors who document grade in real time — logging measurements as grading proceeds rather than after the lift is complete — can have documentation ready for inspector review within hours of lift completion, rather than the 1-3 days it takes to compile from field notebooks and spreadsheets.

A common misunderstanding among contractors transitioning from highway work to airport work is assuming that random sampling is acceptable for grade verification, as it often is for highway compaction testing. AC 150/5370-10 does not allow random sampling for grade elevation documentation. The requirement is systematic documentation at defined intervals — every 50 feet along the lift across the full width.

The systematic interval requirement serves two purposes: it creates a complete spatial record of the lift's grade profile, and it ensures that no section of the lift was built without grade verification. An FAA inspector reviewing a QC binder should be able to determine the grade at any point within the paved area by interpolating between the documented measurement points.

Some contractors have submitted QC packages with random sampling patterns (measuring where convenient, skipping difficult-to-reach areas) and had them rejected during FAA oversight visits. The resulting corrective action — re-documenting grade on a lift that is already covered — is sometimes impossible, requiring the contractor to demonstrate compliance through cores, probes, or other indirect methods. This is expensive and time-consuming.

FAA AIP oversight visits are typically unannounced or scheduled with short notice. During a visit, the FAA program manager or their designated state aviation authority representative will request access to the project QC binder. The inspection follows a specific review protocol:

1. Lift count verification: The inspector counts the number of lift sign-offs in the QC binder and compares to the number of lifts implied by the construction records. Missing sign-offs are immediate findings.
2. Documentation interval check: For a sample of lifts, the inspector verifies that measurements exist at 50-foot intervals for the full width. They typically select one lift near the beginning, one in the middle, and one near the end of the project for this check.
3. Non-conformance and resolution review: Any grade deviations documented in the QC records must have corresponding corrective action records. Unresolved non-conformances are a critical finding.
4. Calibration records: Surveying equipment used for grade documentation must have current calibration records. Expired calibration records can void the associated grade documentation.
5. Inspector identity: The FAA will verify that the individuals who signed the daily inspection reports were qualified per the project's QC plan — typically requiring a certain level of surveying experience and familiarity with AC 150/5370-10 requirements.

See the Sitemark airport construction page for how our platform generates AC 150/5370-10-compliant lift documentation automatically from field measurements. The airport grade verification procedure guide covers the step-by-step field process for compliant grade documentation.