Dec 12 2013

Sikorsky’s Half-Century Workhorse Posted 10 years 131 days ago ago by Admin

Story by Rick Weatherford

Photos by Aris Helicopters

In the early 1950s, the Sikorsky S-55 made its mark when the 600 horsepower (hp) piston-powered helicopter realized its first use in the world of construction. With a typical load of 1,500 lbs, the aircraft would place power poles or lift objects that a ground-based crane was unable to accomplish.  By 1956 when the much more powerful 1,525 hp piston engine S-58 entered service, with its nearly 5,000 lbs of lift, helicopter operators were able to provide the construction industry with a much more capable machine.

The S-58 was used for every conceivable job: placing air conditioners and equipment on top of structures, power line pole placement, moving workers to remote construction sites, lifting loads at job sites, and moving oil and gas equipment in remote areas. The S-58 was used for many other types of construction jobs over the last five-and-a-half decades of service.

In the early 1970s, Sikorsky completed a conversion project that turned the piston S-58 series into the more powerful and reliable twin-engine turbine S-58T.  The helicopter drivetrain stayed the same, but Sikorsky incorporated the well-known turbine PT6 with 1,800 hp “twin pack” engines. The addition of twin-engine turbine power added flexibility and reliability to the S-58, allowing it to function in the offshore transport market and lift loads to higher altitudes during construction and firefighting work.  Now in 2013, there are still working S-58Ts, including some in foreign military services and a handful in commercial service in the United States.

One longtime S-58 operator is California based Heli-Flite, Inc., doing business as ARIS Helicopters with offices in both northern (San Jose) and southern (Riverside) California.   ARIS and Heli-Flite started out as separate companies but merged in 2004, and now operate two S-58Ts, two MD-500Ds, one 206B JetRanger, and a single AS-350B Astar.  The company does lift work, firefighting, government contract work and charter jobs.  The main lift aircrafts are the S-58Ts for loads between 2,000 and 5,000 lbs., while the lighter helicopters cover loads between 500 - 1,500 lbs.

ARIS owner and pilot Scott Donley tells Rotorcraft Pro, “We started as Heli-Flite in 1993 with a piston-powered S-58B.  (A second piston S-58 was added in 1996.)  For certification purposes we converted the S-58B to a S-58F, lowering its internal gross weight to 12,500 lbs from 13,000 lbs.  For external loads we could still go to 13,000 lbs.  Although originally rated at 1,525 hp with 115-octane fuel, when we had to go to the lower 100-octane we lost some power and went to about 1,425 hp.  We stripped the aircraft of all additional weight we could find, including removing cowlings and replacing the wheels and tires.”

“We found the aircraft could easily lift 3,000 lbs, and up to 4,000 lbs on a cool day at sea level.  We also found the aircraft very sensitive to temperature, and when it heated up outside our lift capability would drop quickly.  Because of this we normally tried to do our jobs early in the morning during the coolest time of day.  We flew the pistons until 2009; we miss ‘em.  They proved reliable and able to get the job done.”

Heli-Flite moved to the S-58T in 2004 for a few reasons.  Donley explains, “First, avgas was becoming more expensive, and for the firefighting mission the piston S-58 had fallen out of favor.  We were able to pick up a couple S-58Ts and once we started operating them we knew we had a winner.  It had power even when we went high into the mountains, and the PT6 engine (1,870 hp) was well known for reliability and ability to go to its TBO.” 

With the "new" S-58Ts, Heli-Flite was now able to bid on firefighting contracts that required moving firefighters and using a 420-gallon Bambi bucket.  ARIS pilot Steve Bull, who started with Heli-Flight nearly 20 years ago, describes the S-58T as a very stable firefighting platform with great visibility and good altitude performance.  “When we go higher and hotter we need to cinch the bucket a bit, but in most conditions the helicopter stays strong.  We have been on contract with the state of Oregon, and work routinely with the US Forest Service and CALFIRE on a call when needed basis.”

When it comes to lift jobs, the S-58T routinely lifts 4,000 - 5,000 lbs, even on warm days.  In the Los Angeles basin, where many jobs originate, ARIS can guarantee 4,500 - 5,000 lbs of load lift in almost any condition.

 Bull explains what’s involved in lifting one single piece of equipment to a high-rise building in downtown Los Angeles.  The planning is extensive.  “First, we do a job walk by physically visiting the site to verify the building location, meet the customer, and confirm the date and time along with what we are lifting, such as a new 4,400-lb generator to the top of a 20-story high rise.  We look at where the unit is going to be set in place as well as where we will be lifting the unit from.  The flight could originate from a loading dock or from the street, and usually will require a momentary street closure, which means a street-use permit will be needed.  In addition, we also look for unmarked hazards such as power lines, roof top antennas, banner and phone lines that may cross the road, or loose sheet metal and roofing material.  Anything that could become airborne from the rotor wash, or become entangled with the helicopter or the load being lifted, must be identified and secured, or removed.”

 “We also define the landing zone, emergency landing areas, lift and release points, and the flight path for the equipment being lifted.  We identify control points for crowd pedestrians, other vehicles, etc. and also determine if there’s potential for the load to penetrate the roof, and how many floors may need to be vacated.  We must protect the general public.  In most cases the entire building is vacated.  We also work with surrounding businesses that may have to close until after the helicopter lift is done.  This usually makes the job go on a Sunday, which causes the least impact on them, and means an early morning lift for us.”
 
“Now we take all the information we’ve gathered and must submit a Congested Area Lift Plan to the local Flight Standards District Office (FAA).  Their field inspector will go to the location and verify all the information we’ve submitted, insuring that we have done everything proper, have control points in place to protect the general public, identified potential hazards and corrected them, and that we have sufficient room to land the helicopter, lift the equipment, and place the equipment.  He will contact all other parties, such as local police, fire, and other officials that may require notification of the helicopter lift.”

“The Congested Area Lift Plan has several line items that must be completed, including: site drawing, helicopter type, registration number, category standard, date of lift, time of lift, long line length, max. load weight, operational altitude above building, number of lifts required, a description of the load, whether the building is evacuated, and pilot’s name.”

 “Once we have the approved, stamped plan from the FAA, we then need to pull a city fire permit and get a street use / closure permit. This can take several days.  Five-to-seven working days are normal just for FAA approval.  To accomplish all the tasks involved is a minimum of 15 working days for city approvals.  Bigger jobs can take much longer.  Most customers don’t see the time, effort, and planning involved setting up a helicopter lift job.  They only see how quickly and professionally we get the job done.”
 
So what does the future hold for the S-58T?  After nearly 60 years of operation, how many more years can the S-58 economically operate?  Donley estimates, “We have a parts supply to run our aircraft for at least the next 10 years, and probably 15.  Right now there are a few particular parts that we would like to have more of, and we’re always scouring the world for additional parts.”

“We love the helicopter, I’ve personally flown it for 20 years and it’s a part of me. The S-58T outworks a Huey and lifts a bit more in most conditions.  We know the aircraft inside and out, plus our maintenance personnel keep the aircraft in best flying condition.  At ARIS, we`d like to eventually put a third S-58T back in service, as we lost one a few years ago.  For now we will continue to operate the S-58T for the foreseeable future.  We really see no aircraft that can directly replace it.”