Radome Repairs

Cobham is Europe’s leading radome specialist, with over 40 years’ experience in the design, manufacture and test of radome for civil and military aircraft. The Radome Repair Centre, at Cobham's Stevenage site, specialises in repairs to civil aircraft radomes and structures. Focussing on fast turn times and high quality repairs. Radomes are assessed, with quotes to the customer within 24 hours of receipt. It is a self-contained unit with dedicated staff and facilities for paint stripping, drying, pre-preg and wet lay up repairs, assembly, paint and electrical test.

Of significant benefits to customers is Cobham's approval to design repair schemes for any radome type and for damage lying outside the limits of the structural Repair Manual. This offers the possibility of repair to a radome previously considered Beyond Economic Repair.

The Nordam Connection

Since January 1997, the centre has operated in an alliance with Nordam, Texas, the leading US repair house. In conjunction with another member of the Nordam Group, world Aviation Associates, it serves civil operators throughout Europe. The centre at Stevenage, in southeast England, provides radome repair facilities and supplies Nordam’s patented weatherMaster® radomes.

Radome Repair

Every radome received is thoroughly inspected for damage and moisture ingress, measured over its entire surface. Each assessment is recorded and the damage allocated one of the following five categories:

Cat. 1 – Small indentations, erosion or marks to the surface finish only
Cat. 2 – Ruptures or cracks in one skin only.
Cat. 3 – Ruptures or cracks in one skin or core.
Cat. 4 – Ruptures or cracks in both skin and core.
Cat. 5 – Extensive damage to dielectric requiring replacement down to the base ring.

Repairs are quoted within 24hours of radome receipt.

Overhaul and Repair

The overhaul process involves the removal of lightning strike strips, livery, base coat and primer to expose the outer laminate. Internal and external skins are then removed as necessary according to the type and extent of damage.

The core is examined and carefully replaced where required to maintain the radome’s electrical performance and structural integrity. Use of the correct materials and careful scarfing of joints in the repaired area is essential to recover of the radome’s original; electrical performance. Skins are replaced either by wet lay up or hot bonding to complete the structural repair and reinstate the outer profile.

Assembly

All hardware is refitted and the radome’s coatings. Including primer, base coat, anti-static and livery, can be applied according to the manufacturer’s structural repair manual or individuals customer requirements. Where necessary, rain erosion coating or polyurethane boots can also be applied.

Test

Transmission loss performance of radomes cannot be tested on aircraft. Cobham Stevenage operates a special purpose far field test site to measure transmission loss and, where necessary antenna / radome patterns, including side lobes. The site has been built to meet the requirements of ARTC 4 and RTCA minimum operational performance standards for radomes (MOPS) and can handle radomes ranging in size from those of small helicopters to those of the bowing 747 and Lockheed Martin C130.

Capability

The radome Repair Centre has an extensive capability list covering all popular aircraft types. The list is available on request.

Approvals

UK Civil Aviation Authority, A8 Design Organisation approval reference AD/1811/00.

C-130 Radomes

Cobham at Stevenage has a long tradition of design, manufacture, repair and test of nose radomes for military aircraft. The Radome Repair Centre, a self-contained unit already focussed on the fast turnaround of repairs to civil radomes, also performs fast and efficient repairs to radomes from military transport aircraft. Its expertise includes repairs to the ubiquitous C130 (Hercules) nose radome.

Around 1,100 C130 aircraft are in service in over 50 countries and they are asked to perform the most demanding missions including rapid troop deployment and humanitarian aid all over the world; all-weather operation from unprepared strips is normal. The results of such operations are that many parts, including the nose radome, are exposed to accelerated degradation, often dramatically affecting performance. In the case of the C130’s radome, its fluted core construction permits a significant level of moisture ingress; this particular problem severely reduces radar range, and in extreme cases, degrades the structural integrity of the radome.

At a time when airborne weather radar is becoming more and more important, the electrical performance of the radome protecting it becomes critical. The benefits of a costly new radar fit can be lost if attention is not paid to ensuring that the radome is fault – free.

Radome Repair

Special techniques are required for repair of this unit and Cobham has developed considerable expertise in this area. External paint is first dry-stripped and, where necessary, the radome is oven dried. Cobham has developed methods to expedite complete drying of the fluted core where high levels of moisture are present. Where required, a good-in transmission test may be performed to established local areas of poor electrical performance in the radome wall. On completion of the repair, the radome is painted in accordance with the customer’s requirements and submitted for the test.

Cobham maintains a comprehensive stock of materials and hardware for the radome to ensure a fast repair turnaround.

Test

Since 1995, Cobham has won a number of successive contracts for the repair of nose radomes from the Royal Air Force’s large fleet of C130 aircraft. This has resulted in significant investment in facilities at Stevenage including those for electrical test where a 65metre outdoor range has been adapted to accommodate the C130.

Following repair, the radome is tested on this range. The test site complies with the requirements of ARTC-4 and RTCA MOPS and includes dedicated mounting and handling facilities to accommodate the radome’s 125kg weight.

The comprehensive facility at Stevenage is the only one of its kind in Europe.