RAAF Hercules Maintenance Goes East

Not unexpectedly, there was irritation in the Air New Zealand ranks about protests by Australian States’ authorities over the work going offshore.

Ian Carmichael, aircraft maintenance manager at the Christchurch base, made the point without prompting when Australian Aviation was shown over the base and the RAAF work. “We won purely and simply on competitive manhour rates, the proven ability of the Base to deliver on time and the reputation for quality work”, he said. “The suggestion we’ve heard a number of times that we got the work as tit-for-tat for our participation in the Australian frigate building program is plainly mischievous. ”

The base is ideally set up for overhaul work. It is spacious, with hectares of hard standing and a huge (No. 1) maintenance hangar. The latter is a last legacy left by the old NationalAirways Corporation before it was absorbed into Air New Zealand in the late ’70s. NAC built its extraordinary hangar for 737 and F27 work and it must be one of the largest of its type anywhere. Half of the acreage is given over to this work while the other half accommodates up to four C-130s when the doors are shut.

Within ten minutes towing distance is the paint shop, a near hermetically sealed hangar which can accommodate one C-130 and a cluster of specialist shops, avionics, machining, etc.

Ian Carmichael reckons on an average throughput of five RAAF Hercules a year; of both models, the older E model strategic aircraft and the camouflaged tactical aircraft, the H models. Experience suggests an elapsed time of 29 working days as the minimum OLM time for the H models and up to and possibly more than 43 days for the E models.

It compares favourably with the National Science Foundation aircraft which average 105 working days in the same hangar. “We are driven by the supply rate”, says Graeme Hills, head of base maintenance. “Generally, the RAAF’s supply system for spare parts is quick and smooth, but that’s not so with the US Navy’s system which provides for the NSF aircraft. Besides, the American aircraft tend to be pretty well whacked when they come in – ice flying is tough. ”

Graeme Hills describes it as “one stop maintenance”. All the necessary work is done on base and, with the airframe work, there’s a sizeable capacity to manufacture parts when necessary. While the OLM does not include engines, expertise on the Allison T56s is readily available from the airline’s Auckland base where these engines are overhauled for the RNZAF’s Hercules and P-3B Orions.

On arrival, the aircraft are completely stripped down and examined for cracks and stress corrosion. Ultrasonic detection is used on most stressed areas and, depending on the nature of the area, on site X-ray. Hercules tend to have predictable areas of structural deterioration. Among the most notorious are the two sloping longerons on either side of the rear ramp door. The condition is especially severe on the port side where the C-130’s primitive lavatory is located. The heavy alloy extrusion replacements require careful machining. So too do the heavy track beams located directly over the main undercarriages at station 517. The common replacement of these beams usually requires the fabrication of a number of ancillary parts. Outer mainplane changes, especially on some of the older E models, is likely since they are lifed. Graeme Hills says this presents no problem, especially as they arrive in “stuffed” condition, all plumbing, wiring and mechanics in place.

At present, the base is installing equipment to enable it to carry out repairs with boron fibre. According to Graeme Hills, the RAAF is the only organisation which uses boron fibre to repair stressed structures, including wing planks (elsewhere it is usually a straight metal on metal repair). It is a process of heat blankets and computerised temperature controls, well familiar to the base plastics shop which ranges from vacuum forming to a wide range of composite carbon fibre and honeycomb work.

A major job undertaken in the nearby metal shop has been work on the NSF Hercules skis which, after a season on the ice, arrive in heavily battered condition, usually requiring a whole rebuild. It calls for the replacement of hydraulics and the manufacture of large, milled alloy planks, reinforcing places, heavy bronze bearings and the machining of 20kg bell cranks from solid steel stock.

After resealing between the skin plates, the RAAF aircraft get a repaint. The job in the temperature controlled shop takes two weeks and nearly as much planning as the technical overhaul. The old paint is chemically stripped and the aircraft washed in detergents before the application of 240 litres of cromate primer and 300 litres of top coat. In the interests of weight, total paint thickness is set at between 50 and 80 microns. The job requires an inordinate amount of masking and remasking, especially with the snappy livery on the strategic aircraft (at one stage the aircraft has to be completely covered to prevent a red bloom from the roundel kangaroos).

Polyurethane resonates is toxic, so breathing apparatus is used and electrostatic application eases the job on undersurfaces. Charge hand Murray Everest estimates the total worth of the job on one C-130 is around $250,000. The paint shop operates non stop throughout the year, putting a gloss on aircraft from as far afield as theArab Emirates and Indonesia.

Air New Zealand’s contract engineering business last year topped $NZ65 million (the RAAF Hercules contract is worth about$NZ25m). About $NZ50m of this work was done at Christchurch and the rest at Auckland, but the airline says the Auckland capability is being increased. At present the Auckland base is doing a major (50,000 manhours) overhaul and refurbishment on a former Qantas 747-100. The aircraft had been leased to Air Pacific and was to go to Virgin Atlantic on leaving Auckland.