Project Marshall

CAAS4 - Cost resized

Background and requirement

Project Marshall covers the modernisation of Air Traffic Management (ATM) services at MOD airfields in the UK and UK Overseas Territories. In 2014 Project Marshall was awarded to Aquila, a 50/50 joint venture between Thales and NATS. The purpose of the tasking was to produce a Should Cost Model (SCM) to review Value for Money (VFM) for the ten-year In-Service period of Project Marshall for His Majesty’s Treasury.


TP Group located, normalised, and collated disparate data sources to create an independent view of costs. A Request for Information was designed and executed, pro-actively engaging with suppliers to provide the best possible results. Data was augmented through collaboration with TP Group’s affiliate company, Osprey Consulting Services Ltd, leveraging experience from specialists in the aerospace sector. Bottom-up estimates were used based on Mean Time to Failure and Mean Time to Repair rates of ATM equipment to understand the maintenance burden. Established Cost Estimating Relationships were also exploited to efficiently produce a clear, credible, and detailed Basis of Estimate. Costs were varied and included engineer headcount, consumables based on Mean Time to Failure and Mean Time to Repair rates, salary and overhead costs for day-to-day operations, safety assurance requirements, as well as logistics, risks and opportunities, and cost uncertainty.

Verification and Validation (V&V) was undertaken in collaboration with Strategic Enablers Project Controls, to ensure all models were completed in accordance with Modelling Centre of Excellence (MCOE) V&V standards. An Optimism Bias (OB) assessment was completed in collaboration with key stakeholders within the DT. Sensitivity analysis was used to highlight major cost drivers and provide an assessment of cost maturity.

An in-depth Cost Data Assumption List (CDAL) with detailed commentary on assumptions and methodology, fully cross-referenced to a comprehensive Master Data Assumption List (MDAL) ensured transparency. This allowed key assumptions to be updated easily, ensuring the DT can re-run the model as new information becomes available. User guides and training were provided to relevant DT members ensuring a legacy modelling capability remains.

Probabilistic outputs were structured by Cost Resource Breakdown Structure (CRBS), Departmental Expenditure Limits, and Defence Lines of Development (DLOD’s). Flexibility within the costing structure allowed for more insightful analysis and future use in budgetary reviews and Investment Appraisals.


TP Group went over and above the briefing to create a comprehensive view of all major ATM assets under project Marshall, covering eighty sites and over 4,400 items of equipment, the first of its kind since Project Marshall’s inception in 2014. Whilst supporting the accuracy of the SCM, this also enabled the DT to efficiently conduct large-scale, bespoke analysis.

A report and presentation outlined key findings and identified savings. It also provided clear analysis of the modelled output to enable the DT to determine VFM of Marshall in-service period. It also supported the DT to carefully plan future strategy and confidently negotiate in a targeted manner, helping to shape the future of the Project Marshall.


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