Configure runway end safety area
Sample planning comparisons
| Scenario | Code | Approach | Runway width (m) | Existing L×W (m) | Recommended L×W (m) | Added area (m²) |
|---|---|---|---|---|---|---|
| Regional apron expansion | 3 | Instrument | 45 | 120 × 90 | 265 × 150 | 29,250 |
| Mountain site upgrade | 4 | Precision | 60 | 90 × 120 | 345 × 150 | 40,500 |
| Small strip, visual ops | 2 | Non-precision | 23 | 90 × 60 | 135 × 60 | 2,700 |
Computation logic
- Baseline length from selected planning mode and approach type.
- Adjusted length = baseline × (1 + adjustments%) × safety factor.
- Recommended width = max(baseline width, 2 × runway width).
- Area = length × width.
- Additional area approximates the gap between existing and recommended footprints.
- Volume = additional area × average earthworks depth.
- Cost = volume × earthworks rate + area × surfacing rate.
Step-by-step
- Select a planning mode and approach type.
- Enter runway width and site conditions (slope, elevation).
- Add existing end-safety dimensions to find shortfalls.
- Optionally set average depth and unit rates for budget checks.
- Press Calculate and review results above the form.
- Export using CSV or PDF for your records.
RESA planning scope and constraints
Runway end safety areas reduce consequences when aircraft overrun or undershoot. This calculator supports early construction planning by estimating target length, width, and added earthworks when existing graded areas are limited. Use it to compare alternatives, budget impacts, and phased upgrades before final design drawings.
Baseline sizing inputs and what they represent
Baseline length is derived from the selected planning mode and approach category, then refined with site and operational proxies. Baseline width follows a conservative minimum and a runway-width multiplier. For fast screening, keep defaults and focus on runway width, existing dimensions, approach type, and runway code number.
Adjustment factors that drive length growth
Slope, elevation, traffic intensity, wet-surface risk, and surface type contribute to an adjustment percentage. Steeper slopes and higher elevations can increase stopping distance variability, so the calculator adds conservatism. Higher traffic and frequent wet conditions increase the adjustment, supporting resilient grading decisions and drainage planning.
Quantity takeoff: area, volume, and cost checks
Recommended area equals target length times target width. The added area is approximated from the difference between existing and recommended footprints, then multiplied by average earthworks depth to estimate cut/fill volume. Costs split into earthworks per cubic meter and surfacing per square meter for quick order-of-magnitude budgeting.
Using outputs for layout, phasing, and reporting
Review the recommended dimensions and the additional length or width needed. If land is constrained, test an engineered arresting option to understand how much of the target can be met by a defined bed length. Export CSV for procurement tracking, and PDF for stakeholder reviews and construction coordination.
FAQs
1) Is this a compliance determination?
No. Outputs are planning estimates to support construction scoping. Always validate with the applicable aerodrome authority requirements, published standards, and your project’s certified design assumptions.
2) Why does runway width affect recommended width?
The calculator applies a rule-of-thumb that end safety width should be at least twice runway width, then compares it against a baseline minimum. This keeps side excursions within a graded, recoverable surface.
3) How do slope and elevation change results?
Higher slopes and higher elevations add conservatism by increasing the adjustment percentage. This reflects greater variability in aircraft performance and braking effectiveness, which can influence grading and drainage requirements.
4) What does “additional area” mean here?
It is an approximation of the extra graded footprint needed beyond existing dimensions. The method combines added length and width contributions and avoids double-counting the overlap area.
5) How should I set average earthworks depth?
Use a realistic average from preliminary profiles or survey data. If unknown, start with 0.30–0.50 m for early screening, then refine after alignment, drainage, and geotechnical assumptions are agreed.
6) When should I use the engineered arresting option?
Use it when physical length is constrained by roads, terrain, or property. The tool compares an entered bed length against the planning target, helping you discuss alternatives and phasing with stakeholders.