Merlin’s magical miles of wiring

Electrical wiring harnesses are the lifeblood of modern aircraft and are key to facilitate software and other upgrades. Harnesses and wiring systems within the modern ‘fly by wire' aircraft are an essential part of the design and ensure that all aircraft primary and secondary systems do what they're supposed to. Universal Wiring Systems (UWS) has just completed 407 miles of cabling for AgustaWestland's Merlin Capability Sustainment Programme (MCSP). They are over two thirds through a project for 22 aircraft, each comprising 25 miles (41km) of wiring, with 16 aircraft sets delivered so far. “This is a complex engineering project and one which we have relished working on,” begins UWS' operations manager, Andy Routledge. “It's a tribute to our working partnership with AgustaWestland that we have been able to deliver the 16th harness set, a culmination of 400 miles of wiring, on time and within budget. We're now working flat out to deliver for the next six aircraft.” UWS has a dedicated 14,500ft² facility and a team of over 30 harnessing experts to install the wiring systems, most of whom are trained and certified to IPC620 quality and acceptance standards. The company has also achieved SC21 Bronze award. The MCSP is a significant phase of the Merlin HM Mk1 Weapon System lifecycle. It significantly enhances the Merlin's flexibility in the maritime battle-space of the future. Awarded in 2006, the programme will see 30 of the current Merlin Mk1 fleet upgraded to Mk2. <Built to last> It is clear that the Merlin will be operating in challenging environments, and that its wiring will need to withstand extreme conditions. So harnessing companies, such as UWS need to build in resilience. With 17 years' experience in the sector, and operating as a division of Universal Engineering, UWS ensures its wiring systems are effective and efficient. The company's ruggedised harnesses are designed and built to withstand harsh conditions, using convoluted tubing or fully-sealed moulded encapsulated techniques.  It manufactures some of the largest and technically challenging open wire harnesses in the industry. The largest exceed 12m in length with in excess of 1,500 wires per harness. All wires are individually coded in-house by UV laser, marking wires from small connectors through to complete land systems, enabling the identification of wires whilst limiting the encasing and thereby reducing weight. Sometimes EMC screening or additional harness protection is required – mechanical over-braiding is the solution. Often what is needed is the ability to braid directly onto the harness, with flexible conduit or hoses using a variety of materials including Nomex, tinned copper wire, PTFE and PEEK. The braiding cable can cover bundle diameters ranging from 3 to 30mm. Upon completion, products need to be rigorously and tested for continuity, insulation and resistance. UWS has improved its facilities with the introduction of the DIT-MCO 9000 point analyser, enabling mobile testing of assemblies up to 40ft in length. Day to day the UWS team is now more focused than ever on providing the best harnessing solutions to a wider range of customers. Historically ‘fly by wire' has been common place in fixed-wing aircraft, but now it can be seen in different variants of helicopter. Universal Wiring Systems can provide interconnection designs at full system programme level or one-off prototype harnesses. And though these will rarely be seen by those using the aircraft, they are a key component of the modern helicopters which are helping the UK's armed forces do their difficult work. www.universalwiringsystems.co.uk