Delicate balancing act

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An aircraft hangar may seem like just a large shelter for aircraft while on the ground, but there is more to their design than simply coming up with a shed of the requisite size and shape: function aesthetics, security and environmental performance are just some of the factors that come into play, reports Megan Ramsay

According to Jonathan Jewers, director at UK-based   Jewers Doors Ltd: “The architecture of aircraft hangars is becoming hugely important. Airport owners, MRO (maintenance, repair and overhaul) providers and their architects alike see airports as the gateway into their country and first impressions count! So whether it is a terminal or a hangar, they generally want them to be impressive but must also take into account that they are hangars and will need to be functional. Occasionally architect’s visions have to be reined in slightly to ensure that the ultimate functionality of the hangar is not restricted.”

In particular, there are several design requirements when it comes to aircraft hangar doors, he says. “Foremost is safety, for obvious reasons. Functionality is a requirement to ensure efficient operation of the doors so that aircraft can quickly and easily enter or exit the hangar. Reliability by design reduces the risk of delay to aircraft operations; the cost implications of a grounded aircraft are huge.”

Also significant – and increasingly so these days – is ‘green design’. Jewers points out: “With energy prices soaring globally, a poorly insulated hangar door is not good news. A recent analogy given to me by one architect [based in the hot climate of the Middle East] is, ‘Using a poorly insulated hangar door is like having a fridge and leaving the door open.’”

Robert Aiken, Emirates senior manager engineering facilities, agrees, saying: “In this region [the Middle East], approximately 70% of the electrical consumption is from air-conditioning; this has encouraged us to use material with high insulating properties. Another energy saving feature implemented is that if the hangar doors are open for more than 15 minutes, the chilled water valves on the relevant hangar air handling units close to save energy. The hangars have skylights to allow natural light to enter during the day. This is one very obvious example of a balance; too much natural light may increase the internal temperature of the building. The building management system is used to conserve energy through time scheduling of lighting and air-conditioning,” he explains.

“Environmental considerations are always factored in to the design of our facilities as it is our duty to do whatever we can to help protect the planet. Also, if a project is designed with environmental initiatives considered, this will provide benefits in the operational costs of the facility,” Aiken adds.

Fulfilling the brief
Jewers notes that there are rarely two hangars and doors alike; all design briefs are different and need to be addressed in consultation between the client and supplier at the early design stages. “We work with clients, architects and engineers to develop the design of the doors with their specific demands in mind. We are able to advise what is possible, practical or, indeed, could be budget restrictive,” he informs.

At Jewers Doors, clients are able to get very involved in the design and construction of the hangars and doors and, indeed, often do so, but due to the complexity and size of many projects, such as major international MRO hangars, the client normally employs a full project team, consisting of architect, engineer, quantity surveyor, project manager and main contractor to build and manage the project.

Jewers Doors supplies hangar doors to commercial MRO providers, the military, FBOs (fixed-base operators), airlines, royalty, airports and owners of private hangars. Within just the last 18 months, it has supplied doors to Emirates Engineering, Monarch Airlines, MNG Jet Centre, Turkish Airlines, Martin Baker, The Private Jet Company and many military projects as far afield as the Far East and the Falkland Islands.

Its doors were fitted to a new Turkish Airlines hangar (known by its Turkish acronym HABOM) constructed earlier this year at Istanbul Sabiha Gökçen International Airport. This hangar is being used as an aircraft MRO centre and was designed in conjunction with Turkish companies, entering service in June.

The facility has the capacity to provide simultaneous MRO services for 11 narrowbody aircraft in the dedicated narrowbody hangar and three widebody aircraft in a separate hangar. A section of the widebody hangar can be partitioned off to provide paint services, accomodating either two narrowbodies or a single widebody aircraft.

Dr Ali Genç, senior vice president media relations at Turkish Airlines, confirms: “The priorities for HABOM are functionality and environmental considerations, but safety and security are also critical components. We assume that we have succeeded in building an aesthetic MRO centre while fulfilling all the other requirements at once, without any compromise.”

HABOM represents an investment of about US$550 million by Turkish Airlines’ MRO subsidiary, Turkish Airlines Technic, as it aims to become one of the top five MRO providers in the world. A statement notes that, with the HABOM facilities at Sabiha Gökçen, Atatürk-based Turkish Technic’s narrowbody aircraft maintenance capacity has increased by 57%, and its widebody aircraft maintenance capacity is up by 43%. Besides its facilities at Atatürk and Sabiha Gökçen, it also has a narrowbody hangar at Ankara.

Genç also reveals: “We may have some plans for the construction of a new hangar at the new/third airport to be constructed in Istanbul.”

Elsewhere in Turkey, at Istanbul’s Atatürk Airport, MRO provider MNG Jet opened a new 4,000m2 hangar in June. The company is offering airframe maintenance services as well as NDT (non-destructive testing), wheel and battery shops in the new facility.

Special requirements
Maintenance hangars have specific requirements beyond simply storing aircraft securely. Emirates’ newest maintenance hangars at Dubai International Airport are located on the west side of the existing Emirates Engineering area. The new building has a footprint of 38,000m2, supplementing the pre-existing 182,000m2 facilities, and consists of four fully air-conditioned hangars designed for various aircraft maintenance activities.

The hangars can comfortably accept all aircraft types, including the A380, and incorporate an elevating nose docking system; a high-capacity aircraft cabin air-conditioning system; cranes covering fuselage and engine areas; a 15-tonne hoist for engine handling; aircraft ground power installations; power supplies for high-capacity hydraulic rigs; a fuel venting system; two cargo lifts; pre-conditioned air supplies from hangar floor pits; power supplies from hangar floor pits; compressed air and water supply evenly distributed around the hangars and workshops; WiFi throughout; and fire detection, alarm and suppression system as per National Fire Protection Association (NFPA) requirements.

In addition to the hangar bays the facility has four workshops, stores for aircraft materials/tooling, a canteen overlooking the airport and offices. The contract for constructing the facility was awarded to WJ&P on 21 March 2012, with the completed hangars being handed over on 25 June this year.

Aiken comments: “With turnkey projects you may have less influence on the selection of certain equipment and installations, resulting in the delivery of a facility that does not live up to the client’s full expectations. In my experience, there are few contractors or consultants who have an all-encompassing knowledge of aircraft maintenance facility requirements. With the best intentions they may not deliver exactly what is required. Therefore they will always need the assistance of specialists in certain fields.

“On the other hand, if a project is to be split into separate sub-contracted packages, challenges could arise in the co-ordination and interfacing of installations. Also there may be a need for larger client project representation.

“Having an established relationship with a capable contractor with a proven track record in MRO facilities and ensuring that all requirements are clearly understood from the onset is a great starting point. However, care must be taken in the preparation of detailed specifications that clearly describe the complete requirements,” he says.

Rubb expertise

Hangars for military aircraft also have specific design requirements. But according to Rubb Buildings managing director Ian Hindmoor, developments in military hangar design feeds into civilian solutions. He observes: “We use our experience and knowledge from working on Urgent Operational Requirements (UORs) for the UK military to quickly complete hangar facilities within very tight project timescales. Organisations in the civilian sector can also benefit from elements of our military range, including our innovative Heli-Door system and roof-mounted crane technology.”

UK-headquartered Rubb designs and manufactures custom-made relocatable engineered fabric structures, including aircraft hangars, at its plants in Tyne and Wear as well as in the US and Norway.

During 2014 the company has been involved in a number of projects. The UK’s National Police Air Service (NPAS) needed a new helicopter hangar after moving its Dorset base from the county’s police headquarters to Bournemouth Airport. Rubb helped NPAS meet that requirement with a custom-designed aircraft hangar measuring 26 metres in width by 17 metres in length, with 7.5 metre high sidewalls. A Rubb Heli-Door in the front gable provides a clear opening of 21.5 metres wide by 5.5 metres high. The rear gable end includes a 4 x 4 metre roller shutter door and one personnel access door. Each sidewall includes an additional personnel door for access and egress. The Rubb ‘BE’ aviation structure features Rubb’s traditional galvanised internal steel frame and a tapered lattice leg design. The building is clad with durable PVC Ferrari fabric, providing Sargaso blue walls and roof.

Elsewhere, Belgian helicopter operator Noordzee Helikopters Vlaanderen, which specialises in business aviation services, has opted for an aircraft storage facility that comes from Rubb’s Expeditionary Forces Aircraft Shelter System (EFASS) range. The storage and maintenance hangar will be used by NHV to service two Airbus Helicopters EC175s. It is 20 metres wide by 44 metres long, and has a closed rear gable end. Access is through a 17.7 metre wide by 5.5 metre high Heli-Door. The door is electrically operated via two slow-moving helical geared motors, with emergency hand operation capability. This system does not require a base foundation or ramps. Locking and safety devices operate automatically.

The EFASS hangar’s aluminium framework has been designed to maximise strength while minimising weight. The structural aluminium is annodised black and steel components are hot-dipped galvanised to protect from corrosion. The tough PVC covering tensioned membrane forms a protective barrier between the environment and the aircraft and equipment inside. This hangar is clad with double skin insulated fabric panels to accommodate and facilitate HVAC procedures.

And in the very far south-west of the UK, a Rubb aviation hangar building project has assumed a prominent position at Aerohub, the country’s only aerospace-focused Enterprise Zone, based in Newquay, Cornwall. The project provides a large, bespoke space for Apple Aviation Group’s MRO operations. Hindmoor remarks: “The Rubb team constructed the main steel framework for the hangar in April 2014 and then fixed Thermohall insulated PVC cladding to the structure to create its roof and walls. The Rubb hangar provides 25,000 square feet (2,323m2) of aircraft storage and maintenance space. It measures 47 metres in width by 50 metres in length, with 8 metre high sidewalls and an overall height of 18 metres. A Megadoor measuring 43 metres in width by 14 metres at its highest point provides access to the hangar.”

Rubb will also be providing additional aircraft hangar facilities for the UK Ministry of Defence and Lithuanian Air Force in the near future.

Hindmoor notes: “We work very closely with our clients, from initial enquiry through to design, manufacture, installation and beyond. Every civilian and military aircraft hangar is custom-designed and manufactured to suit our clients’ requirements and their range of aircraft, MRO operations and logistical needs… Most of our design and production processes are completed in house. Installation is mostly completed by Rubb’s own construction teams.”

While functional capacity plays a very important role in hangar design, alongside timescales and budgets, aesthetic considerations are also important – particularly in the civilian sector. However, he observes: “More and more commercial organisations are favouring Rubb’s military EFASS product for their civilian ventures due to the practical functional advantages they provide.

“Rubb has seen a trend for increased need for rapid deployment structures and has responded with ongoing development and innovation of the EFASS portfolio. There have been requests for the system to support all kinds of craft from fixed-wing, rotorcraft and UAVs (unmanned aerial vehicles) to land vehicles and MRO activity. There has been an increased demand for this product in the civilian aviation sector,” Hindmoor concludes.