● FIELD INSIGHTS FROM ACTIVE ENGAGEMENTS | Gelephu International Airport, Bhutan  ·  Rodrigues Airport Expansion, Mauritius

CNS/ATM Consultancy Blog

Technical Insights & Field Notes

Perspectives drawn from live international CNS/ATM advisory engagements — greenfield airports, complex procurement environments, and ICAO compliance challenges.

Specifying a Full CNS/MET Suite for a Himalayan Greenfield Airport: Lessons from GLU

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 project sits at the intersection of precision approach infrastructure, complex meteorology, and one of the most demanding outdoor operating environments in South Asia. Getting the specifications right at the RFQ stage is the most important investment a bidder can make."

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:

Navigation ICAO CAT I ILS comprising a 14-element Localizer (LLZ) array and M-type Glide Path (GP) antenna, integrated with co-located DME (100W/1kW dual-rated). The LLZ siting position requires particular attention — a safety-critical discrepancy in the employer's specification was identified and formally raised as part of the pre-tender clarification register.
Communications EUROCAE ED-137 compliant Voice Communication Control System (VCCS) with 6 Controller Working Positions (CWPs), a full VHF and HF radio suite, and an Aeronautical Message Handling System (AMHS) with IWXXM binary format support for modern MET data exchange.
Surveillance ADS-B Ground Station with full ASTERIX Category 021 output, ERA-equivalent performance level, providing cooperative surveillance coverage aligned with ICAO's global ADS-B transition programme.
Meteorological Suite A full AWOS airfield suite, two ceilometers, a Radar Wind Profiler (RWP), a Scanning Coherent Doppler LIDAR, and a C-Band Dual-Polarization Weather Radar. Critically, both the LIDAR and C-Band Radar were reclassified from optional to mandatory base scope following our pre-tender technical review — a material change that significantly affects bid pricing.

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.

ILS CAT I (LLZ + GP + DME) VCCS ED-137 (6 CWP) VHF / HF Radio AMHS / AFTN (IWXXM) ADS-B (ASTERIX CAT 021) AWOS Airfield Suite Ceilometer (×2) Scanning Coherent Doppler LIDAR C-Band Dual-Pol Weather Radar Radar Wind Profiler (RWP) RVR · ATIS / D-ATIS IEC 62305 Lightning Protection IP66 Environmental Hardening

Building a Credible Budget Baseline for CNS/NAVAIDS Expansion on a Remote Island Airport

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.

"Good budgetary work is not a rough estimate — it is a structured cost model that a programme manager can use to make decisions. The difference matters enormously when presenting to a capital committee or engaging with potential vendors for the first time."

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.

ILS / NAVAIDS VHF Communication ATC Automation Interface Surveillance Systems Meteorological Equipment Power / UPS Infrastructure ICAO Annex 10 & 14

Why Pre-Tender Technical Advisory Is the Highest-Value Investment in Airport CNS/ATM Procurement

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.