FAA airspace screening · Part 77 + tower line-of-sight
Screen Part 77 & line-of-sightbefore you file a 7460.
LOS Analyzer tells developers and consultants — in minutes — whether a proposed structure penetrates FAA Part 77 surfaces or breaks a control tower's sightline to the runway. Terrain-aware, curvature-corrected, and ready to generate your Form 7460-1 draft. One screening, $499.
- Standard
- 14 CFR Part 77 surfaces & ATCT line-of-sight
- Terrain + curvature + refraction
- Public validation scoreboard
The stakes
A hazard determination can kill a project.
If a structure penetrates a Part 77 surface and the FAA issues a Determination of Hazard, the project can lose financing, get redesigned, or be scrapped outright — sometimes after months of work. Yet the only way most teams find out is to file a 7460-1 and wait, or to commission a full airspace study that costs $5,000–$15,000and takes weeks.
The free FAA OE/AAA tool only evaluates your structure after you file, and it doesn't model terrain-aware tower line-of-sight at all. So the highest-stakes question — "is there even a problem here?" — is the one that's hardest and slowest to answer.
Full airspace study
$5k–$15k
- 2–6 week turnaround
- Pay before you know feasibility
- Slow to iterate on massing
- Overkill for a go / no-go check
LOS Analyzer screen
$499 · minutes
- ✓ Answer before you file
- ✓ Part 77 + tower line-of-sight
- ✓ Terrain & curvature modeled
- ✓ 7460-1 draft generated
Why it works
Three reasons consultants and developers screen here first.
Instant, terrain-aware Part 77 + LOS
Drop in an airport and a proposed structure and get an immediate read on whether it penetrates the Part 77 primary, horizontal, conical, approach, or transitional surfaces — and whether it breaks the control tower's line of sight to the runway. Modeled with real terrain, earth curvature, and atmospheric refraction, not a flat 2D guess.
A validated engine, with the scoreboard to prove it
Most tools ask you to trust a black box. LOS Analyzer ships a public validation scoreboard — named test cases whose expected outcomes are verifiable by construction from the documented geodesy. The math is on the table, and real FAA-case validation is being added in the open.
Generates your Form 7460-1 draft
When the screening points to a filing, you don't start from a blank page. LOS Analyzer produces a multi-page PDF report and a pre-filled FAA Form 7460-1 (Notice of Proposed Construction or Alteration) draft from the same inputs — ready for your engineer to review and submit.
No black box
A validation scoreboard you can audit.
High-stakes regulatory calls deserve a tool that shows its work. Every release runs a suite of named test cases whose expected outcomes are verifiable by construction from the documented geodesy — curvature drop, chord interpolation, and Part 77 surface elevations — so you can check the math without running the code.
Honest scope: the current scoreboard proves the engine is internally self-consistent with its own formulas. Validation against published real-world FAA determinations is being added in the open — we'd rather tell you exactly what's proven than imply more.
Read the full methodology| ID | Case | Result |
|---|---|---|
| A1 | Structure above midpoint LOS — BLOCKED | ✓ PASS |
| A5 | Runway beyond radio horizon — BLOCKED | ✓ PASS |
| A7 | Part 77 approach penetration detected | ✓ PASS |
| A9 | Part 77 horizontal penetration detected | ✓ PASS |
| A10 | Compliant structure below horizontal surface | ✓ PASS |
| B2 | High-terrain field (DEN-class) blockage | ✓ PASS |
Excerpt — full scoreboard and intake form for real FAA cases live in the repository's validation suite.
Where it fits
A pre-screen, in its proper place.
LOS Analyzer sits at the front of the obstruction process — informing whether (and how) to file, never replacing the FAA's determination or your professional engineer.
- 01
Site concept
Developer / designer
- 02
LOS Analyzer screen
← you are here
- 03
Form 7460-1
Notice of construction
- 04
OE/AAA study
FAA aeronautical review
- 05
Determination
Hazard / no hazard
Clear result → support a simpler 7460-1. · Penetration detected → refine the design before you file.
Trusted by the people who file
Built with airspace consultants and near-airport developers.
Placeholder — design-partner logos go here once usage rights are confirmed.
"Testimonial pending — capture a real quote from a design partner here."
Context: On replacing a $7k pre-screen with a $499 self-serve run.
"Testimonial pending — capture a real quote from a design partner here."
Context: On catching a Part 77 penetration before the design review.
FAQ
The questions filers actually ask.
Do I need to file an FAA Form 7460-1?
Generally, yes if your construction or alteration is more than 200 ft above ground level, is on an airport, or sits within the FAA's notice radius and penetrates a sloped notice surface — 100:1 within 20,000 ft of a runway longer than 3,200 ft, 50:1 within 10,000 ft of a shorter runway, or 25:1 within 5,000 ft of a heliport (14 CFR Part 77, Subpart B, §77.9). LOS Analyzer screens these criteria for your specific site so you know before you commit to a design.
What is Part 77?
14 CFR Part 77 defines a set of imaginary surfaces — primary, horizontal, conical, approach, and transitional — projected around every public-use airport. An object that penetrates one of these surfaces may be an obstruction to air navigation and triggers an FAA aeronautical study. The surfaces' shape and elevation depend on each runway's approach classification, which is exactly what the screening computes.
Is this a substitute for an FAA determination?
No. LOS Analyzer is a preliminary screening that tells you whether — and how — to file. Only the FAA issues an official Determination of No Hazard or Hazard through the OE/AAA process, and a licensed professional engineer should review the structural specifics before anything is submitted. We are deliberate about where the tool stops and a PE begins.
How accurate is the analysis?
The engine is terrain-aware (elevation from OpenTopoData) and corrects for earth curvature and atmospheric refraction (k = 7/6, ITU-R P.834). Every assumption and limit is published in the methodology, and a validation scoreboard documents named test cases with outcomes verifiable from the formulas. It is a screening model: real determinations also depend on runway visual-range requirements, exact tower-cab geometry, and FAA specialist judgment that no automated tool reproduces.
How much does it cost?
A single screening report is $499 — a fraction of the $5,000–$15,000 and multi-week turnaround of a full airspace study. Firms that file often can buy a 5-pack at $380 per report or an annual seat for unlimited screening. No subscription required to run your first one.
Not sure if your site needs a filing?Read the 7460 guide →
Know before you file. Run a screening in minutes.
Place the airport, drop in your structure, and get a Part 77 + line-of-sight determination with a 7460-1 draft — for $499, not five figures.