How do I do a Part 77 obstruction analysis?

Enter obstacle coordinates and elevations with the runway data, and AvPlot evaluates each point against the 14 CFR Part 77 imaginary surfaces and the AC 150/5300-13B approach (OCS) surfaces, flagging penetrations. Results export as a layered DXF.

What surfaces does an obstruction analysis check?

The Part 77 primary, approach, transitional, horizontal, and conical surfaces, plus the AC 150/5300-13B obstacle clearance surfaces, reporting the penetration amount for each obstacle.

What is a Part 77 penetration?

It is an object that extends above an imaginary surface. Penetrations must be evaluated for their effect on airport operations and may require marking, lighting, removal, or a procedure change.

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Obstruction Analysis

FAR Part 77, OCS 7 departure, and AC 150/5300-13B approach Surfaces 1–6 penetration analysis — beta

Airport (optional — prefills runway)

RunwayStep 1

Set from aircraft (optional — sets AAC + classification)

Sets both runway ends’ AAC, ADG, TDG, and classification (≤ 12,500 lb → Small/Utility). Visibility & approach stay manual.

Low end (near threshold)

High end (far threshold)

Airport elevation (ft MSL) Blank = assumed max runway-end elevation (recorded as an assumption).

ObstaclesStep 2

Coordinate system (all obstacles)

ID	Description	Northing	Easting	Top elev MSL	AGL ht	Existing	Ground elev	Survey date	Disposition

Up to 500 obstacles. Paste from a spreadsheet below.

Paste from spreadsheet (tab/comma rows: ID, Description, Y, X, TopElevMSL, AGL)

Analyze & ExportStep 3

DXF mode

Project name (DXF)