What Part 77 and TERPS surfaces apply to my runway?

AvPlot's Airspace Surface Reference returns the applicable 14 CFR Part 77 imaginary surfaces (primary, approach, transitional, horizontal, and conical) and the TERPS and AC 150/5300-13B approach surfaces by runway type and approach.

What is the difference between Part 77 and TERPS surfaces?

Part 77 imaginary surfaces define obstruction-evaluation airspace for notice and ALP purposes. TERPS surfaces (FAA Order 8260.3) protect actual instrument approach procedures and are generally steeper and procedure-specific.

What is the Part 77 primary surface?

It is a surface longitudinally centered on the runway, extending 200 ft beyond each end, whose width of 250 to 1,000 ft depends on the runway's approach type per 14 CFR 77.19.

Airspace Surface Reference

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Quick-reference lookup for the airspace surfaces that define what may exist above and around the airport — 14 CFR §77.19 · AC 150/5300-13B §3.6 & §3.11 (airspace OFZ) · FAA Order 8260.3 (TERPS). Companion to the Runway Linework Generator (this tool is display-only — no CAD/KMZ export). Select your runway parameters; surface families populate as inputs resolve.

Runway parameters

Runway approach type Drives Part 77 category, AC 13B surface set & TERPS card

Approach visibility minimum 14 CFR §77.19 / AC 13B Tbl 3-3, 3-4 breakpoints

Height Above Touchdown (HAT) APV only: precision (PIR) if HAT < 250 ft (or vis < ¾ SM) — 14 CFR §77.19

Airplane size / approach-speed class Selects AC 13B visual Surface 1/2/3 & IT-OFZ small/large branch

Approach Light System (ALS) present Required for the Inner-approach OFZ (§3.11.3)

Aircraft Approach Category (AAC) Drives Part 77 category (per linework engine) & circling category

Airplane Design Group (ADG) Context / RDC label & IT-OFZ wingspan term

Part 77 imaginary surfaces

AC 13B approach / departure

Airspace OFZ (IA / IT / POFZ)

TERPS surfaces

This tool covers airspace / vertical surfaces only. Values are reproduced from 14 CFR §77.19, AC 150/5300-13B (Chg 1) §3.6 and §3.11, and FAA Order 8260.3 (TERPS, current ed. 8260.3G). AC 13B approach/departure surfaces are distinct from 14 CFR Part 77 imaginary surfaces (per §3.6.1) and reflect only the visual segment of an instrument approach — full TERPS final-segment OCS (W/X/Y surfaces) are glidepath-dependent and assessed by the FAA Flight Procedures Team; the TERPS card lists standard planning constants only, not a substitute for a published IFP. Ground-level runway-protection areas (RSA, ROFA/OFA, RPZ, Runway OFZ) are intentionally excluded — see the RSA / ROFA / ROFZ Reference and Runway Linework tools. Always verify against the current source documents and a published instrument approach procedure before use in official submittals.