Preparing RSA/ROFA Documentation for an ALP Update

RSA and ROFA: what each one protects

The two safety areas are concentric rectangles around the runway, and they protect different things. Getting the distinction right is the whole point of the documentation.

• RSA — Runway Safety Area. A defined surface surrounding the runway, graded, drained, and capable of supporting aircraft, ARFF equipment, and snow-removal equipment in the event of an excursion — an undershoot, overrun, or veer-off — without causing structural damage to the aircraft. It must be clear of objects except those whose location is fixed by function (e.g., NAVAIDs that must be in the RSA), and those must be on frangible mountings.
• ROFA — Runway Object Free Area. A larger surface centered on the runway centerline that must be clear of above-ground objects protruding above the RSA edge elevation, except objects fixed by function. The ROFA is about object clearance, not load-bearing capability — it does not have to support aircraft, it has to be unobstructed.

Both are dimensioned by the Runway Design Code, so neither number means anything until the RDC is settled. RSA and ROFA widths and the lengths beyond each runway end come straight out of the AC 150/5300-13B design tables, keyed to the runway’s AAC and ADG.

Step 1 — Settle the Runway Design Code first

Every RSA/ROFA dimension flows from the RDC, so the first task is to confirm it. The RDC combines the Aircraft Approach Category (AAC) — an approach-speed band — with the Airplane Design Group (ADG) — a wingspan/tail-height band — both taken from the runway’s critical aircraft. If the master plan changes the critical aircraft, the RDC and therefore the safety-area dimensions can change with it, so confirm you are documenting against the design aircraft, not just the busiest one.

Step 2 — Pull the standard dimensions

With the RDC fixed, read the required RSA width, RSA length beyond the runway end, ROFA width, and ROFA length beyond the runway end from the design standards. Never transcribe these from memory or a prior study — the controlling values live in the standards tables, and the change history matters (Change 1 to 13B is the current basis). The point of the documentation is that each dimension is traceable to its table.

Step 3 — Survey and overlay existing conditions

The compliance question is not “what is the standard” but “does the existing condition meet it.” Overlay the required RSA and ROFA on surveyed ground truth and look for anything that breaks the surface:

• RSA grading and load capacity. Slopes outside the allowable range, drainage that ponds, or ground that cannot support an aircraft are RSA deficiencies even when nothing is “in the way.”
• Objects in the RSA or ROFA. Roads, ditches, fences, signage, buildings, parked equipment, and terrain that protrude above the safety-area surface — each is either fixed-by-function (and frangible) or a nonstandard condition.
• Insufficient length beyond the runway end. The most common deficiency: the RSA/ROFA cannot extend the full required distance beyond the end because of terrain, water, a road, or a property line.

Step 4 — Document nonstandard conditions

Where the existing condition does not meet the standard, the ALP narrative must state the deviation explicitly, not paper over it. For each one, record the required value, the existing value, the shortfall, and the planned disposition — correct it, request a Modification of Standards, or mitigate with declared distances. A clearly disclosed nonstandard condition with a path to resolution is what FAA review expects; an undocumented one is what gets the submittal returned.

Declared distances as RSA/ROFA mitigation

When the full RSA or ROFA cannot be provided beyond a runway end, declared distances (TORA, TODA, ASDA, LDA) are the standard tool to publish reduced usable lengths so that the available safety area is adequate for the distances actually declared. This lets a runway stay compliant without acquiring land or relocating a road that physically cannot move — and the ALP must show how the declared distances reconcile with the safety areas.

What the ALP has to show

The finished safety-area documentation, in narrative and on the ALP drawing set, ties together:

1. The RDC and the critical aircraft it derives from.
2. The required RSA and ROFA dimensions, each cited to its standard.
3. The existing dimensions and conditions from survey.
4. Every nonstandard condition, its shortfall, and its disposition.
5. Any declared-distance mitigation and how it reconciles with the safety areas.

Built in that order, the analysis is self-defending: a reviewer can trace every number back to a table and every deviation to a disclosed plan.

This article is a reference summary for planning use, not a substitute for the governing FAA text. Citations refer to AC 150/5300-13B (Airport Design, RSA §3.10, ROFA §3.12, Appendix H declared distances), AC 150/5000-17 (Critical Aircraft and Regular Use Determination), and FAA ARP SOP 2.00 (Standard Operating Procedure for FAA Review and Approval of Airport Layout Plans). Always verify dimensions and nonstandard-condition dispositions against the current governing documents and your FAA regional office before issuing a design product. See the full airport planning glossary or the AvPlot toolkit.