Airspace Surface Reference — Tool Guide
The Airspace Surface Reference is a quick-reference lookup for the airspace surfaces that define what may exist above and around an airport — the 14 CFR Part 77 imaginary surfaces (primary, approach, transitional, horizontal, conical), the AC 150/5300-13B approach/departure surfaces, the airspace Obstacle Free Zones (inner-approach, inner-transitional, POFZ), and the TERPS surfaces. You give the runway's approach type, visibility minimum, and aircraft class; the applicable surface families populate, each color-coded and carrying its FAA citation.
It replaces flipping among 14 CFR Part 77, AC 150/5300-13B, and Order 8260.3 to assemble the surface set by hand. It is the airspace companion to the Runway Linework Generator and is display-only — no CAD/KMZ export.
Open the Airspace Surface Reference →Who It's For & When to Use It
Airport planners doing obstruction and airspace work — ALP airspace drawings, Part 77 notice questions, obstruction-analysis setup, and design-report airspace narratives. Use it when you need to know which imaginary and airspace surfaces apply to a runway end and their defining dimensions, or to settle the recurring Part 77-versus-TERPS question for a specific approach.
How to Use It
- Set the runway approach type. Visual, non-precision instrument (NPI), approach with vertical guidance (APV), or precision approach (ILS / GLS / PAR). This drives the Part 77 category, the AC 13B surface set, and the TERPS card.
- Set the approach visibility minimum. Breakpoints follow 14 CFR §77.19 and AC 150/5300-13B Tables 3-3 / 3-4, selecting the Part 77 approach width and the AC 13B surface dimensions.
- Set the airplane size / approach-speed class. Selects the AC 13B visual approach Surface 1/2/3 and the small/large branch of the inner-transitional OFZ.
- Indicate the ALS and design code. Whether an Approach Light System is present (required for the inner-approach OFZ per §3.11.3), plus the AAC and ADG for the Part 77 category and the inner-transitional OFZ wingspan term.
- Read the surface families. Four toggleable families populate as the inputs resolve — Part 77 imaginary surfaces (amber), AC 13B approach/departure (cyan), airspace OFZ / IA / IT / POFZ (violet), and TERPS (emerald) — each card citation-stamped.
- Copy or share. The URL mirrors your selections (
?approach=&vis=&size=&als=&aac=&adg=), so the address bar restores the exact configuration; the Print report assembles the resolved surfaces with citations.
Key Features
- Four surface families in one view. Part 77, AC 13B approach/departure, airspace OFZ, and TERPS — color-coded and individually toggleable.
- Part 77 aligned to the linework engine. The Part 77 surfaces here resolve from the same rules the Runway Linework Generator draws, so the reference and the CAD output agree.
- Citation on every card. Each surface cites its source (14 CFR §77.19, AC 13B §3.6 / §3.11, or Order 8260.3).
- Shareable URLs & session persistence. Selections round-trip through the query string and are restored on return.
- TERPS planning card. Lists standard TERPS planning constants alongside the regulatory surfaces — clearly labeled as planning constants, not a published procedure.
FAA References
- 14 CFR §77.19 — civil-airport imaginary surfaces (primary, approach, transitional, horizontal, conical).
- AC 150/5300-13B Chg 1 §3.6 & §3.11 — approach/departure surfaces and the airspace Obstacle Free Zones (inner-approach, inner-transitional, POFZ). AC 13B approach/departure surfaces are distinct from Part 77 imaginary surfaces (per §3.6.1).
- FAA Order 8260.3 (TERPS, current ed. 8260.3F) — instrument-procedure protection surfaces; the card lists standard planning constants only.
Limitations & Disclaimers
AvPlot is technical planning production support — accurate enough for design reports, planning studies, and ALP narratives. It is not a replacement for stamped engineering or construction documents. Always verify against the current source documents and a published instrument approach procedure before use in official submittals.
- Covers airspace / vertical surfaces only. Ground-level runway-protection areas (RSA, ROFA/OFA, RPZ, Runway OFZ) are intentionally excluded — use the RSA/ROFA Reference and Runway Linework tools.
- Full TERPS final-segment OCS (W/X/Y surfaces) are glidepath-dependent and assessed by the FAA Flight Procedures Team; the TERPS card is planning constants, not a substitute for a published IFP.
- Display-only — there is no CAD/KMZ export from this tool; the Runway Linework Generator produces the drawable Part 77 / OFZ geometry.
Related Tools
- Runway Linework Generator — draws Part 77, OFZ, RSA/ROFA, and RPZ as CAD-ready linework (guide).
- Obstruction Analysis — evaluates points against Part 77 and OCS surfaces (guide).
- RPZ Dimensions — the ground-level Runway Protection Zone that pairs with the approach surface (guide).
Tips & Best Practices
- Set the approach type first — it cascades into every other input's available options and the surface set that appears.
- Toggle off the families you don't need (for a notice question, leave only Part 77) to keep the card stack focused.
- Carry the resolved Part 77 set into Obstruction Analysis so the reference and the evaluation use the same surfaces.
- Paste the URL into project notes; it documents the exact approach/visibility/class basis behind the surfaces you cited.
Related Articles
- Part 77 vs TERPS Surfaces — what each surface set protects and why they differ.
- How to Prepare an FAA Obstruction Analysis — putting these surfaces to work in an obstruction evaluation.