The maintenance and logistics behind keeping big helicopters such as the tandem-rotor Columbia Helicopters 234 and the Erickson Aviation S-64 Air Crane flying can seem downright daunting.

For starters, there is the entourage of personnel, containers, equipment and vehicles that must accompany each aircraft. Columbia operates a mixed fleet of six 234s and eleven 107 Vertol IIs. And it just acquired a half dozen U.S. Army surplus Boeing CH-47D Chinooks it hopes to start operating under the restricted category (no passengers) next year. All but one of the 234s is deployed internationally. Rotating maintenance crews of 10, five on and five off, are assigned to each 234 and a crew of five, half on and half off, go with a 107. And then there is all the stuff that comes along.

“There’s quite a support package that goes with the aircraft to maintain it in the field,” said Roy Toavs, Columbia’s director of maintenance. The “package” includes cranes, slings, hoists, ground power units, hydraulic mules, pickup trucks, service vans and trailers. Some of the service trucks on domestic deployments were once owned by snack maker Frito Lay. Columbia calls them “chip trucks.”

On international jobs with the 234s, everything is packed into four 20-foot and one 40-foot ocean-going conex containers. The 40-footer provides major storage for rotable dynamics. One 20-footer functions as the line shack for the daily ins and outs and houses the logbooks and hand tools; the second is climate-controlled for parts; a third to shield small items from the weather and for overhauls and house field change replacements, wheels and special tools; and the fourth is for consumables, rags, grease and lubricants.

The story is much the same at Erickson, where each Air Crane is accompanied into the field by a 10,000-gallon fuel tanker, lift truck and large custom-built service trailer that contains pressure washers, generators, night lighting, tools and parts large and small–including a spare and monstrously large main rotor blade (the S-64 has six main rotor blades and a disk diameter of 72 feet). Altogether each S-64 is dispatched with $1 million worth of parts and four ground vehicles and a crew of eight, according to Andy Mills, Erickson’s general manager for Air Crane operations.

Away from Home,Operating in Challenging Conditions

It might be years before these large rotorcraft make their way back to their home bases in Oregon for maintenance, so everything–from the preflight once-over to heavy level-D inspections and engine and rotor blade change-outs–is done in the field, usually in the elements, in climates as diverse as Alaska, Afghanistan, Papua New Guinea and Peru.

“Our helicopters don’t always go to the most favorable spots on the globe. We’re working in rain, hail, sleet and snow,” said Columbia’s Toavs. And if the weather isn’t enough, sometimes there is dangerous political instability that makes the job even more interesting. Sometimes, people shoot at you.

Aside from the elements and the sheer size and complexity of these machines, there is one other complicating factor: Many are old. One reason Columbia was so keen to acquire the Army CH-47Ds was that they were built in the 1990s. The average age of Columbia’s 234 fleet is 31 years; 48 for the 107s. Erickson’s S-64s, although extensively overhauled and in some cases remanufactured with many improvements, date back to the 1960s. These aircraft need a lot of TLC to keep flying, sometimes up to 12 hours of maintenance per day.

Along with dealing with the idiosyncrasies of aging engines, mechanical systems and airframes, corrosion looms large as an omnipresent menace. “The main thing we have found through the years is making sure the [aircraft] structure has a good coat of paint on it,” said Columbia’s Toavs. “Making sure the finish is good. If the finish is good, corrosion doesn’t get down to the base materials. Along with that is constant cleaning. The guys out there [mechanics] are always ragging it down. Part of their daily inspection procedure is a rag in one hand and a screwdriver and a flashlight in the other. And every time they get up on that aircraft they wipe it down. There is a lot of surface area on these machines.”

Still, despite the diligence and the TLC, things break. To ensure a steady supply of parts, both companies have obtained the type certificates, many supplemental type certificates and parts manufacturing authority for their iconic legacy aircraft, the 234 and 107 at Columbia and the S-64 at Erickson, and both companies maintain substantial in-house manufacturing and MRO capabilities. Erickson also recently acquired the TC for the Air Crane’s ravenous (550 gph for the pair) Pratt & Whitney JFTD12-5A turboshafts (4,500 shp each) and has begun manufacturing parts for them. This fall the company will begin testing a new all-composite main rotor blade for the Air Crane that should enable it to carry heavier loads, especially in high/hot conditions.

Last year Erickson acquired the rotorcraft assets of Evergreen Aviation as well as Brazil’s Air Amazonia. Almost overnight, the company’s fleet grew from 20 Air Cranes to 90 helicopters, many (like the S-64) of them legacy models such as the Puma, S-61 and Bell 212 and 214, aircraft long since out of production with spotty or non-existent OEM support.

Kerry Jarandson, Erickson vice president for manufacturing and MRO, sees this as a growth opportunity for his company. “Our core competency is supporting legacy aircraft. When it comes to 214s and Pumas, we are positioned to support those aircraft in a vertically integrated fashion,” he said. Someday, when it runs out of old surplus CH-54 fuselages, the military progenitor to the S-64, Erickson might even delve into manufacturing completely new Air Cranes.

At Columbia, Toavs said, “There is never a dull moment. Everybody here comes together to make it work.” Mechanics are assigned to a specific N-number aircraft and generally stay with it for years, learning its specific peculiarities. “It works well for us to keep that,” he said.