14 CFR Part 77 · Field tool for inspectors

Imaginary surfaces. Real-time answers, in the field.

Part 77 Inspection computes the imaginary surfaces for the airport you're standing at, shows which surface controls and whether an object penetrates — and captures the defensible record on your iPhone, before you leave the site.

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§77.19 surfaces on-device Works offline Inspection-grade records
Isometric diagram of FAR Part 77 imaginary surfaces around a runway Primary, approach, transitional, horizontal and conical surfaces surrounding a runway, with one obstruction penetrating the approach surface flagged at plus 23 feet and one clear tower at minus 41 feet. TWR 0117 · CLEAR −41 FT BELOW SFC OBS 0041 · MET TOWER APPROACH SFC · +23 FT PENETRATION HORIZONTAL · 150 FT AAE CONICAL · 20:1 APPROACH · 50:1 APPROACH · 34:1 TRANSITIONAL · 7:1 PRIMARY
14 CFR §77.19 surfaces · live penetration check
Built around the inspections states already perform — FAA 5010 Airport Master Record·state airport permit programs·obstruction evaluation screening

The gap

The airspace math lives at a desk. The inspection happens in the field.

Every obstruction question is a geometry problem — which imaginary surface controls at this exact point, and does the object break it? Today the tools that can answer it never leave the office.

Desktop GIS

Does the surfaces, misses the field

GIS suites and airspace analysis software generate beautiful Part 77 surfaces — on a workstation, hours or days after you were standing next to the obstruction.

Field inspection apps

Does the checklist, skips the math

Airfield inspection apps capture photos and discrepancies just fine. None of them can tell you whether that new tree line penetrates the transitional surface.

Consultants

Bridges the gap at study prices

When the answer really matters, agencies wait on an obstruction evaluation study — quoted per site, delivered in weeks. Fine for a runway extension; overkill for an inspection finding.

Obstruction data for each runway approach is a required element of the FAA 5010 airport inspections states already perform. Part 77 Inspection is that section of the job — done in minutes, in the field, with a record you can defend.

Workflow

From runway data to determination in four steps.

01

Pick the airport

Surfaces generate instantly from published runway data — primary approach transitional horizontal conical — sized by runway class and approach type per §77.19.

02

Sight the object

Stand at the obstruction or sight it with the camera. GPS and AR fix the position; enter, estimate, or measure the height.

03

Get the answer

The app resolves the controlling surface at that exact point and reports clearance or penetration in feet, on the spot — no connectivity required. The call stays yours; the geometry is no longer a guess.

04

Capture the record

Photos, heights, coordinates, and the result bundle into a time-stamped inspection record — exportable for the 5010 file, a permit packet, or a 7460 referral.

Concept interface · pilot builds now in the field

Capabilities

Built for the way inspections actually go.

Offline surface engine

Full §77.19 geometry computed on-device from runway class and approach type. No signal at the airfield? Doesn't matter.

GPS + AR sighting

Fix an obstruction's position from where you stand — or sight it through the camera when you can't walk to it.

Instant penetration math

Controlling surface, surface height at the point, clearance margin or penetration depth — in feet, while you're still standing there.

Defensible records

Time-stamped photos, coordinates, heights and results — exportable to PDF and CSV for the 5010 file or a permit packet.

5010-aligned workflow

Organized by airport and approach end to match the Airport Master Record's obstruction elements — it slots into the inspection you already run.

Every public-use airport

Nationwide airport and runway data on board — pull up surfaces for the strip you're visiting today, not just your home field.

Who it's for

Made for state inspectors. Useful on every desk that touches Part 77.

Primary

State aeronautics divisions

5010 and permit inspections with the obstruction section done on-site instead of back at the office.

Airports

Operations & planning staff

Answer "can that crane go there?" before the phone call ends — and log it.

Consultants

Aviation consulting firms

ALPs, master plans and obstruction studies with field verification in the same tool.

Land use

Planners & ALUCs

Review development near airports against real surface geometry, not a paper overlay.

Siting

Crane, tower & wind teams

Screen a site against Part 77 before you commit to the 7460 filing.

Pilot program · Summer 2026

Run it on a real inspection.

We're selecting a small group of state aeronautics agencies, airports and consultancies for free field pilots. Bring us on a live 5010 or permit inspection — we'll prove the time and the record quality, side by side with your current workflow.

  • Free during the pilot — no procurement, no commitment
  • Ride-along support on your first inspections
  • Your feedback steers the §77.21 / §77.23 roadmap

Request a field pilot

A person reads every one of these — you'll hear back within two business days.

No lists, no spam — just a reply from the people building it.

FAQ

Straight answers.

Is the app's output an official FAA determination?+
No — and it isn't trying to be. Official determinations come from FAA obstruction evaluation (Form 7460-1 via OE/AAA). Part 77 Inspection is the advisory field analysis that makes your inspection record faster, consistent, and better-supported — and tells you when something deserves a referral.
Which surfaces does it model?+
Civil airport imaginary surfaces under 14 CFR §77.19 — primary, approach, transitional, horizontal, and conical — with dimensions driven by runway class and approach type. Military (§77.21) and heliport (§77.23) surfaces are on the roadmap, prioritized by pilot feedback.
Does it work offline?+
Yes. Airport and runway data ride along on the device and the surface math runs locally, so determinations work at airfields with zero coverage. Records sync when you're back in range.
What does it cost?+
Pilots are free. In production, pricing is a flat annual subscription per agency or organization — sized to fit small-purchase thresholds, never per-inspection. You'll never be charged for doing more inspections.
When can I get it?+
We're onboarding pilot partners now, with iPhone and iPad beta builds delivered through TestFlight. Request a field pilot above and we'll schedule around your inspection calendar.