The verdict in three sentences
In an engineering consultancy, resource planning software should not be judged by its licence price but by the utilisation rate it wins back: with 60 consultants at a 750 EUR day rate, a single point is worth about 99,000 EUR of revenue per year. An off-the-shelf PSA (30 to 70 EUR per user per month) is enough as long as your processes are standard. Once percentage-of-completion billing, multi-site time-and-materials work for aerospace clients and margin per project become central to management, a custom tool at 50,000 to 90,000 EUR pays for itself in under two years.
What the tool must cover in an aerospace consultancy
Most engagements run as time and materials or fixed price at large aerospace and space prime contractors. Management relies on four building blocks: the consultants' resource plan (who is available, when, with which skills and security clearances), time and expense capture, billing (monthly T&M, fixed price by completion, milestones) and real margin per project, consultant and client.
The classic problem: the resource plan lives in a spreadsheet, time in one tool, billing in the accounting ERP. As a result, bench time is spotted too late, change orders are not rebilled and margin is only known at year end.
| Functional block | Off-the-shelf PSA | Custom | Measurable impact |
|---|---|---|---|
| Resource planning and staffing | Standard, view by skill | View by clearance, client site, programme | 1 to 3 points of utilisation |
| Time and expenses | Web and mobile entry | Mobile entry, rules per client contract | Monthly close on day 2 instead of day 8 |
| Percentage-of-completion billing | Partial, often via export | Native: T&M, fixed price, milestones, change orders | 1 to 2% of unbilled revenue recovered |
| Margin per project | Generic dashboards | Real margin with loaded cost per consultant | Day-rate decisions at renewal |
| Payroll and ERP integration | Standard connectors | Connectors to your existing tools | No more double entry |
| Skills management | Basic profiles | Skills matrix, certifications, CV export | Tender answers in 2 hours instead of a day |
Three-year cost comparison
The figures below are 2026 estimates for 60 consultants and 8 managers, i.e. 68 users.
| Item | Entry-level PSA | High-end PSA | Custom |
|---|---|---|---|
| Licence or initial build | 30 EUR x 68 x 12 = 24,480 EUR per year | 70 EUR x 68 x 12 = 57,120 EUR per year | 50,000 to 90,000 EUR one-off |
| Configuration and data migration | 5,000 to 10,000 EUR | 15,000 to 30,000 EUR | Included |
| Maintenance and hosting | Included | Included | 8,000 to 14,000 EUR per year |
| Cumulative 3-year cost | 78,000 to 83,000 EUR | 186,000 to 201,000 EUR | 74,000 to 132,000 EUR |
| Fit with your billing rules | Low | Medium | Full |
| Ownership of code and data | No | No | Yes |
| Time to go live | 1 to 2 months | 3 to 4 months | 4 to 6 months |
The entry-level PSA remains the cheapest, but it handles percentage-of-completion billing and client-specific rules poorly. The high-end PSA covers more, at a recurring cost that exceeds the custom option from year two.
How to choose without getting it wrong
Ask yourself three questions. What share of your revenue is fixed price? Above 30%, completion-based billing must be native. How much time do your managers spend consolidating the resource plan? If it is more than half a day a week, your current tool is already expensive. Do you know your margin per project every month? If not, you are negotiating day-rate renewals blind.
A sound approach is to start with a staffing and timesheet module delivered in 8 to 10 weeks, then add billing and margin in a second phase.
Mini case study
Thomas, managing partner of a London aerospace engineering consultancy, runs 60 consultants at a 750 EUR day rate over 220 billable days. His utilisation rate is 84%. The firm invests 72,000 EUR in a custom tool, plus 10,000 EUR a year in maintenance.
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- Theoretical billable capacity: 60 x 220 x 750 EUR = 9,900,000 EUR.
- One point of utilisation: 99,000 EUR of revenue.
- Target gain: 2 points by spotting bench time 3 weeks earlier, i.e. 198,000 EUR.
- Better rebilling of change orders: 1% of actual revenue, about 83,000 EUR.
In year one, the gross gain is close to 280,000 EUR for 82,000 EUR of cost. Even halving that gain to stay conservative, payback comes in under 8 months.
FAQ
Is an off-the-shelf PSA enough for 60 consultants?
Yes, if more than 80% of your engagements are simple T&M and you accept its standard rules. Budget 30 to 70 EUR per user per month, i.e. 24,000 to 57,000 EUR a year for 68 users.
How long does a custom tool take to go live?
Allow 4 to 6 months for the full scope, with a first staffing module usable after 8 to 10 weeks. Migrating the resource plan and skills profiles takes about 2 weeks.
Can the tool connect to our payroll and accounting software?
Yes, through standard exports or APIs. The accounting connector usually represents 5,000 to 10,000 EUR of the overall budget.
How do we measure the real gain?
Track monthly utilisation, time-close delay and unbilled revenue. A gain of 1 point of utilisation with 60 consultants is worth 99,000 EUR a year.
Is our aerospace clients' data secure?
Local hosting, strong authentication and access logging are written into the specification from day one. These requirements add 3,000 to 6,000 EUR to the project.
Let's scope your project. We define the scope with you (staffing, time, billing, margin), an indicative budget between 50,000 and 90,000 EUR and a schedule in 8 to 10 week phases. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
