Project Controls Suite
R-28: What-If Scenario Comparison Report
Data Date: 28 Feb 2026
What-If Scenario Comparison Report
Multi-Scenario Analysis: Sequential Build vs Fast-Track vs Design-Build — Northgate International Airport Expansion — Terminal 3
Earliest Possible Completion
Dec 2028
Scenario B — Fast-Track
Lowest Total Cost
$1.24B
Scenario A — Sequential
Lowest Risk Profile
Scenario A
Highest float, proven method
Recommended Scenario
B — Fast-Track
Best risk-adjusted outcome
CP Length Spread
24 mo
Between fastest and slowest
Scenario Summary — Side-by-Side KPI Comparison
Scenario A — Sequential Build
Traditional sequential phasing: Foundations → Structure → MEP → Fit-Out → Commissioning. Minimal concurrency, full design completion before each phase. Low rework risk.
End Date
Dec 2029
Total Cost
$1.24B
CP Length
47 months
Peak Headcount
620
P80 Schedule Risk
+5.2 mo
Top Risk
Design scope creep
Recommended
✗
Feasible — Not Recommended
Recommended
Scenario B — Fast-Track
Overlapping design and construction phases. Foundation works commence on 30% design. Structural steel ordered on Design Development. Higher design contingency budgeted (8%).
End Date
Dec 2028
Total Cost
$1.41B
CP Length
35 months
Peak Headcount
920
P80 Schedule Risk
+7.1 mo
Top Risk
Rework from IFC changes
Recommended
✓
Best Risk-Adjusted Outcome
Scenario C — Design-Build (Single Contractor)
Single design-build contractor takes full design + construction responsibility. Maximum concurrency, fixed lump-sum price. Owner retains less design control. Contractor takes full scope risk.
End Date
Jun 2028
Total Cost
$1.68B
CP Length
23 months
Peak Headcount
1,450
P80 Schedule Risk
+11.4 mo
Top Risk
Contractor insolvency / QA
Recommended
✗
High Risk — Not Recommended
Multi-Scenario Comparison Matrix
| Parameter | Scenario A — Sequential | Scenario B — Fast-Track ✓ | Scenario C — Design-Build | Best |
|---|---|---|---|---|
| Project End Date | Dec 2029 | Dec 2028 | Jun 2028 | C (but high risk) |
| Total Project Cost (P50) | $1.24B | $1.41B | $1.68B | A |
| Cost Contingency (%) | 5% | 8% | 15% | A |
| Critical Path Length | 47 months | 35 months | 23 months | C (but very risky) |
| Peak Workforce | 620 | 920 | 1,450 | A |
| Average Total Float (non-CP) | 38d | 22d | 8d | A |
| P80 Completion Date | May 2030 (+5.2 mo) | Jul 2029 (+7.1 mo) | May 2029 (+11.4 mo) | B (risk-adj.) |
| Design Change Risk | Low | Medium | High | A |
| Rework / Abortive Work Risk | Low | Medium (8% allowance) | High (15% allowance) | A |
| Owner Design Control | Full | Full | Reduced | A/B |
| Supply Chain Complexity | Standard | Elevated | High (single point) | A |
| Contractor Insolvency Risk | Low (multiple) | Low (multiple) | High (single) | A/B |
| Airport Operational Disruption | Moderate (4 yr) | Lower (3 yr) | Lowest (2 yr) | C (but high risk) |
| Revenue Loss — Foregone | $480M (47 mo) | $360M (35 mo) | $224M (23 mo) | C (but high risk) |
| Overall Recommendation | Feasible, not preferred | RECOMMENDED | Not Recommended | Scenario B |
Visual Metric Comparison (Normalized to Scenario A = 100%)
Total Cost
CP Duration
Schedule Risk (P80)
Peak Workforce
Scenario Analysis Recommendation — Scenario B: Fast-Track Delivery
Scenario B (Fast-Track) is recommended as the optimal risk-adjusted delivery strategy for the Northgate Terminal 3 Expansion, based on the following analysis:
- Time vs. Cost trade-off: The 12-month schedule advantage over Scenario A (Dec 2028 vs Dec 2029) yields $120M in additional airport revenue during the recovered operating period. The $170M cost premium for Scenario B is therefore net-positive by approximately $50M over a 10-year NPV model.
- Scenario C rejected: While Design-Build offers 6 months' further time saving over Scenario B, the cost premium ($270M more than A) and concentrated contractor risk (single point of failure, 1,450 peak workforce) create unacceptable exposure. The P80 schedule risk of +11.4 months means Scenario C's headline completion date of Jun 2028 has only 20% probability of being achieved — effectively pushing the P50 outcome into 2029, eliminating the time advantage.
- Risk mitigation for Scenario B: The key risks of rework from IFC design changes and mid-construction scope additions must be managed through a robust AFC freeze protocol and design freeze gates at each phase boundary. An 8% design contingency (included in the $1.41B estimate) is adequate to cover expected rework volumes based on comparable airport expansion projects.
- Key decision milestone: Scenario B procurement strategy (multi-package traditional contracts) requires the appointment of a Design Manager by 01 May 2026 and completion of the Employer's Requirements document by 01 Jul 2026 to maintain the Dec 2028 target.
- Decision required by 28 Mar 2026 to allow competitive tender issuance for foundations package on 15 May 2026 — the first critical milestone for the Scenario B schedule.