Technical Insights & Field Notes

Great Nicobar Island International Airport (GNIIA) is a greenfield international airport planned at the southern end of the Andaman & Nicobar archipelago in the Bay of Bengal. Our consultancy has been engaged for specialist engineering and pre-tender consultancy on the airport's Communication, Navigation, Surveillance and Meteorological systems. The work runs from the Design Basis Report through siting studies, layouts, technical specifications and a Bill of Quantities, to support during the tender phase.

Unlike a bid-support assignment, where the specification already exists, this engagement starts upstream. The design basis we set now will govern equipment selection, civil interfaces and maintenance philosophy for the life of the airport. That makes the early engineering decisions the most consequential ones.

Designing for a Marine, Cyclone-Prone Environment

Island airports sit in one of the harshest corrosion environments an outdoor CNS installation can face. Salt-laden air, persistently high humidity and heavy monsoon rainfall attack antennas, shelters, cable terminations and earthing systems alike. The design basis therefore calls for marine-grade protective coatings and corrosion-resistant hardware, sealed and conditioned equipment shelters, and masts and antenna supports engineered for cyclone-zone wind loading under IS 875 (Part 3). Lightning protection and earthing are designed to IEC 62305, reflecting the region's high thunderstorm activity.

Siting on a Constrained Coastal Site

NAVAID and sensor siting is being developed through coverage studies and obstacle and clearance assessments against ICAO Annex 10 and Annex 14 and the AAI CNS Manual siting criteria. On a coastal greenfield site with natural terrain and dense vegetation, protecting ILS critical and sensitive areas, DVOR clear zones and surveillance line-of-sight has to be planned into the master layout from the outset. Retrofitting it after civil works begin is far costlier.

Redundancy as a Design Principle

With no neighbouring aerodrome close enough to act as a practical fallback, continuity of air navigation services depends on redundancy built into every layer: dual power sources with UPS backup for each CNS facility, diverse communication paths for ATS voice and data links, and monitoring and control designed for remote fault diagnosis. Quantities and costs are being prepared on a CPWD DSR and market-rate basis, with island logistics and freight reflected realistically so that the tender estimate holds up when bids arrive.

The New Gelephu International Airport (GLU) in the Kingdom of Bhutan represents one of the more technically demanding CNS/ATM procurement programmes our consultancy has engaged with. Situated in the ecologically sensitive southern foothills of the Himalayas, this ICAO CAT I greenfield development for the Department of Air Transport (DoAT) requires a complete SITC supply of Communication, Navigation, Surveillance and Meteorological systems — all specified and procured within the constraints of challenging mountain terrain and an extreme environmental envelope.

The Environmental Hardening Imperative

One of the first challenges in developing the technical specification package for GLU was ensuring every outdoor system was properly rated for the site's environmental realities. The southern Himalayan foothills combine high humidity, extreme temperature swings, and significant wind exposure — conditions that standard equipment specifications frequently underestimate. For this programme, all outdoor masts, radomes, and sensors have been specified with:

• Wind survival: 200 km/h for all outdoor structures and antenna systems
• Humidity: 100% relative humidity with IP66-rated, moisture-controlled field cabinets as mandatory
• Operating temperature: –40°C to +70°C for all outdoor units

Any vendor submitting a quotation for GLU that does not address these environmental parameters is, in effect, quoting for the wrong project. This is a recurrent issue in international airport programmes where vendors apply standard product configurations without adapting to site-specific requirements.

The Full Technical Scope

The CNS/MET scope at GLU is comprehensive. Our consultancy has developed a Compliance Bill of Materials (BoM, Rev 2) mapping every line item against ICAO Annexes 10, 11, and 14 requirements. Key systems include:

Structuring the Deliverables Package

The advisory deliverables produced for this programme illustrate the depth of technical engagement required for a project of this complexity. Beyond the BoM, our team developed a multi-section Estimated Cost Model (ECM, Rev 1), a comprehensive Technical Execution Plan (TEP — document ref. GLU-CNS-TEP-001 Rev 1) covering ILS siting, shelter infrastructure, HVAC design, power load calculations, and commissioning sequences, plus a full Strategic RFQ Package (GLU-RFQ-CNS-MET-001) and a Pre-Bid Query Register addressing over 30 technical clarifications across all system categories.

Each deliverable serves a specific function in the bid process — the BoM for compliance assurance, the ECM for pricing validation, the TEP for execution credibility, and the RFQ for vendor engagement. Together they form the technical foundation from which a credible, compliant EPC bid can be constructed ahead of the May 2026 submission deadline.

Remote island airports present a distinct category of infrastructure procurement challenge. Rodrigues — the outer island of the Republic of Mauritius — combines logistical constraints with a growing need for enhanced CNS and NAVAIDS capability. Our engagement on the Rodrigues Airport Expansion project was focused on a specific but critical phase of programme development: establishing a credible, structured budgetary cost baseline ahead of formal tendering.

Early-stage cost estimation on airport infrastructure programmes is frequently undervalued. Yet the quality of pre-tender budget work determines whether programme managers secure adequate capital approval, whether tender documents are realistically scoped, and whether the eventual procurement process attracts competitive bids or results in a single-vendor scenario driven by budget uncertainty. On this engagement, we developed a submission-ready multi-BoQ workbook — structured to enable modular scope scaling and phased capital expenditure alignment.

The Multi-BoQ Approach

Rather than producing a single consolidated equipment cost estimate, the Rodrigues workbook (CNS_Budgetary_Quote_v2) was structured as a multi-BoQ document — separating individual system categories so that programme managers could model different scope configurations independently. This approach directly addresses a common programme management challenge: capital approval committees often need to see costed options, not a single take-it-or-leave-it figure.

The workbook covers the full CNS and NAVAIDS equipment suite, with system-level cost breakdowns, a financial optimisation log identifying value engineering opportunities, and procurement-stage recommendations cross-referenced against ICAO Annex 10 and Annex 14 compliance requirements.

Financial Optimisation and Compliance Mapping

Alongside the cost workbook, we conducted a financial optimisation review identifying areas where alternative specification approaches, phased procurement sequencing, or value engineering could reduce the overall programme cost without compromising ICAO compliance. The compliance mapping component produced a system-level cross-reference against Annex 10 (Communications and Navigation standards) and Annex 14 (Aerodrome design and operations), ensuring that budgetary scope decisions do not inadvertently create regulatory gaps.

In competitive international airport infrastructure programmes, the quality of a bid is determined long before the submission deadline. The technical advisory work carried out in the weeks and months preceding a bid submission — specification interpretation, BoM development, cost modelling, pre-bid clarification — has a disproportionate influence on bid outcomes compared to any work done in the final submission rush.

Our experience across active CNS/ATM programmes in Bhutan and Mauritius reinforces this consistently. In both engagements, the most consequential advisory inputs occurred during the pre-tender phase: identifying ambiguities in employer specifications, reclassifying equipment scope items that were incorrectly designated as optional, flagging siting errors in ILS layouts, and establishing cost baselines grounded in current market intelligence rather than historical assumptions.

The Cost of Specification Misinterpretation

Specification misinterpretation is one of the most common and most costly errors in airport CNS/ATM procurement. The consequences range from a bid that is technically non-compliant (and therefore disqualified) to one that is priced materially under scope — leaving the contractor exposed to variation claims throughout the project lifecycle. Independent advisory provides a structured check on both risks: compliance is verified against ICAO Annexes before submission, and scope is validated against the employer's intent rather than a vendor's standard product configuration.

What Structured Pre-Bid Advisory Delivers

Across our current engagements, structured pre-bid advisory has delivered six core outputs: a compliance-verified Bill of Materials, a validated cost model with benchmark pricing, a Technical Execution Plan that demonstrates delivery credibility, a formal RFQ package that controls vendor engagement, a pre-bid clarification register that protects against post-award disputes, and — critically — a set of safety-critical technical flags that the bid team might not otherwise have identified without specialist CNS/ATM knowledge.

For EPC contractors and equipment vendors bidding on ICAO-governed airport programmes, the investment in independent CNS/ATM technical advisory is not an overhead — it is a risk management measure with a clear and measurable return. To discuss advisory support for an upcoming bid, visit our Services page or contact us directly.