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Wednesday, February 1, 2012

At the Controls: Sikorsky S-92 & S-76D  

Rotor & Wing Editor-at-Large Ernie Stephens at the controls of the Sikorsky S-76D as part of a Dec. 8 demo flight. The S-76D shares the same sleek, elegant lines as earlier variants, but comes equipped with a state-of the-art Thales cockpit, composite rotor blades, and a set of Pratt & Whitney Canada 210S engines

By Ernie Stephens, Editor-at-Large

Rotor & Wing Editor-at-Large Ernie Stephens at the controls of the Sikorsky S-76D as part of a Dec. 8 demo flight. The S-76D shares the same sleek, elegant lines as earlier variants, but comes equipped with a state-of the-art Thales cockpit, composite rotor blades, and a set of Pratt & Whitney Canada 210S engines. See story below.

Since 2009, the economy has ravaged many sectors of rotorcraft industry. Corporations have cut back on flying, and some public service operations have shuttered their hangars altogether. But the good news is that the offshore industry, with its gas and oil exploration endeavors, managed to dodge the bullet. That was good news for the folks at Stratford, Conn.-based Sikorsky Aircraft, because only a few years before, it had introduced the S-92, a hefty-size helicopter that was exactly what the offshore industry needed.

Many oil and gas companies drilling in the Gulf of Mexico have pushed farther away from the shore, so they need a helicopter with good reach, high seating capacities, and the muscle to tote lots of people and equipment. The S-92 surfaced as the rotorcraft of choice for several operations around the world, including Cougar Helicopters of St. John’s, Newfoundland; PHI in Lafayette, La.; and Brunei Shell Petroleum based in Seria, Brunei Darussalam.

However, the S-92 is not a one-trick pony. It is a medium, twin-engine helicopter with a stand-up cabin that can be completed for a variety of missions, including executive transport, cargo hauling, military applications, and air ambulance service. In the back is a huge, cabin-width door that opens into a cargo ramp, or, in the VIP role, accesses a cavernous baggage compartment apart from the passenger area. At the forward end is a state-of-the-art flight deck that will do everything for the pilot, but order lunch.

While a Sikorsky crew was passing through the Washington, D.C., area showing off a brand new S-92 in a special Legacy of Heroes commemorative livery—a paint scheme depicting soldiers, firefighters and police officers in silhouette—I was invited to take it for a spin. Stafford Regional (RMN) is a sleepy little airport in rural Virginia about 34 nautical miles southwest of the District of Columbia. That made the 60-foot long, 15-foot tall S-92 look supremely out of place amidst the Cessna 172s parked nearby.

Inside the FBO, I met Les Gerrard, the senior applications engineer on the S-92 program; Stacy Sheard, a program test pilot, and Joel Vigue, another of the test pilots. They briefed me on the lineage of the program, the general capabilities of the aircraft, the avionics, and the local weather conditions—all of which were impressive. It was now time to go flying!

The gunmetal grey aircraft, s/n 920146, was the 146th ship of its kind to roll off the assembly floor at the Coatesville, Pa. plant, and was showing just about 50 hours on the Hobbs meter. Others in the fleet have been in service around the world in offshore drilling support, SAR operations and VIP service since its FAA certification back in 2004. The model was also the first aircraft to be certified under the newer, more rigorous safety standards adopted by the European Aviation Safety Agency/Joint Aviation Authorities.

When it comes to size, the S-92 is no Chinook, but it certainly is large. When I stepped inside, I found seating for about 15 passengers—22 is the maximum—in webbed, fold-down crew seating affixed with their backs to the wall. And because it was built as a SAR demonstrator as well, there were three fold-up patient litters along the starboard wall, leaving the rest of the cabin with the utilitarian look one would expect in a SAR configuration.

Up front in the cockpit, pilot Joel Vigue was already strapped into the left seat, leaving me the other side to occupy. So, I stepped through the cockpit door, and belted myself in.

The flight deck is about the size of the front office in a UH-60 Black Hawk, and was equipped with four color, multi-function displays (MFDs), with a blank center position for a fifth one. The massive center console and overhead panel were loaded with all of the usual radios, switches and knobs, which Vigue was already configuring for our flight. Between the pedals that could be moved closer and farther away, and the nicely cushioned seat that could be adjusted in four directions; this 250-lb. writer had no problem finding a comfortable position for piloting.

The field of view from the cockpit of the S-92 is excellent. The center windshield post and windshield wipers, which park vertically, weren’t bothersome, and the wide windshields and side windows offered a good look at everything throughout a better-than-180-degree sweep. Two small windows overhead were nice, but the chin windows weren’t good for much more than checking the polish on my boots. (They just don’t show enough out the front of the aircraft.) The instrument panel was just right: not too high, not to low, not too deep, and not too shallow. And the engineers were kind enough to keep the height of the panel lower on the ends than in the middle, making it easy to see over while on approach.

Vigue already had the two General Electric CT7-8A engines—rated at 2,520 shp each—online with the S-92’s four-bladed, fully articulated main rotor, and canted four-bladed tailrotor system. All that was left to do was to take a quick look at the numbers being displayed on the Rockwell Collins Pro Line IV instrument suite, which we both did. With everything well in the green, I was awarded the controls.

Picking up the S-92 was uneventful. The ship, which was approximately 18,000 lbs. as loaded (about 8,500 lbs. less than its max gross takeoff weight), got light on its gear, and came up nose first, as is common with wheeled helicopters. It granted me a nice, stabilized hover about 15 feet off the ground before I pulled it into a normal takeoff.

The S-92, like most rotorcraft its size, has a couple of trim triggers on the collective and cyclic which, when squeezed, allow the flight controls to move with the ease of a much smaller helicopter. Let them go, and the controls immediately adopt that position, allowing the pilot to relax a bit. They aren’t locked there, mind you. They’re just trimmed to that position. However, I wanted to get to know this aircraft, so I kept the triggers in through climb out, crosswind, and a bit of the downwind. I’ve flown a lot of helicopters for Rotor & Wing, but this was one of the quickest to get comfortable with. Because after just a few minutes on the controls, it was clear to see that the S-92 wanted to “talk” to its pilot. Feedback through the cyclic was just enough to let me know that I had her full cooperation, but light enough to feel like I was in something several thousand pounds lighter. Even the information on the Rockwell Collins MFDs were easy to interpret; not that there was much to stare at. The ship was holding airspeed, heading and altitude without a fuss, and the gages showed that the engines were barely breaking a sweat, let alone being overworked.

Under most conditions, my first approach in an aircraft under evaluation would be a normal one to the numbers. But I actually felt so comfortable with N146UK, I asked Vigue to advise local traffic that we would be extending our downwind, in anticipation of a run-on landing.

At a little less than a mile off the approach end of the runway, I brought the aircraft through a base leg, and turned final. The ride down was a non-event. The infamous “clothes line” we were all taught to slide down felt like it was actually running through the centerline of the aircraft as we coasted down. Tweaking the descent and hauling it back to the recommended run-on landing speed of 50 KIAS was more a matter of thinking about it than commanding it.

For grins, I decided to do it at 46 KIAS, and had no trouble holding exactly that all the way to the touchdown zone. A bit of aerodynamic braking just after touchdown, and toe brakes at 34 KIAS, brought the aircraft to a smooth stop without so much as a shutter.

Next on the menu was a maximum performance takeoff, which I spoke to Vigue about first, since he was the one the company signed the aircraft out to. I think he was waiting for me to ask, so he could make the recommendation that he loves making during all S-92 demonstrations.

“Try it with your feet off the pedals,” he said.

I replied: “Excuse me?” After all, snatching-in a boatload of power is as much an exercise in pedal work as it is in collective control, right?

Well, to ease pilot workload, Sikorsky equipped the S-92 with an anti-torque hold system that takes over as soon as the pilot removes his or her feet from the pedals. But barely touch a pedal, and the system’s micro-switch will know, and instantaneously understand that you’re back in command. (At least that’s how Vigue said it worked.)

Performance

Maximum Gross Weight

26,500 lbs

12,020 kg

Maximum Cruise Speed 151 kts 280 kph
Maximum Range - No Reserve 539 nm 999 km
HIGE Ceiling 9,000 ft 2,743 m
HOGE Ceiling 6,500 ft 1,981 m
OEI Service Ceiling 5,000 ft 1,524 m
AEO Service Ceiling 15,000 ft 4,572 m

Powerplant and fuel system
Number of Engines 2
Engine Type GE CT7-8A
Take-off Shaft horsepower (5 min) 2,520 shp 1,897 kw
OEI Shaft horsepower (30 sec) 2,740 shp 2,043 kw

Accommodations
Cabin Length 20 ft 6.1 m
Cabin Width 6.6 ft 2.0 m
Cabin Height 6.0 ft 1.8 m

From a hover, I pulled the collective smartly, with my size 11 boots flat on the floor, and one eye on the compass. Up we went. The magnetic compass might as well have been glued in its housing, because it didn’t rotate by so much as a degree, not even after I reached 50 feet and was pushed the nose over to dial up some airspeed. (I believe I heard the aircraft laugh just a bit.)

After a couple more takeoffs and landings, Vigue suggested we depart the pattern, so I could check out a few of the other features of the S-92.

Coupling up the four-axis autopilot to put us on a departure course gave me time to take a better look at the other features. Just about everything you’d expect to find on the flight deck of a business jet was here, plus some. The engineers packed this aircraft with a 500-parameter health and usage management system (HUMS), traffic collision avoidance system (TCAS), enhanced ground proximity warning system (EGPWS), navigation management system, weather radar, optional rotor anti-ice system and a host of other tools.

Of special interest was an in-flight diagnostic system. If you suspect that one of the four main rotor blades—or one of the four tail rotor blades, for that matter—isn’t playing well with the others, it’s no problem. The ship can perform a track and balance examination of all eight blades, and make the appropriate adjustments to permanently correct the problem while cruising at altitude; a nice feature, since 70 percent of all S-92s delivered are used in offshore support missions.

N146UK, designated Sikorsky’s Legacy of Heroes S-92 aircraft, was specially painted to salute the contributions of U.S. military, fire, rescue, and police personnel, whose silhouettes appear on each side. In October 2011, it began a six-month world tour that included scheduled stops throughout the Americas, Asia and India.  Photo by Ernie Stephens

But that’s not all. If a VIP or litter patient is getting too rough of a ride, that same set of force generators can be commanded to smooth out the ride in that passenger’s particular zone. Sikorsky built this aircraft with SAR in mind, so it comes equipped with an autopilot that will fly a hands-off, crew-defined search pattern over water. It has a hard time holding grid and spiral searches over the kind of terrain found in central Virginia, so it had a tough time when I tried it. But having flown the same system over Long Island Sound, I can testify that it works well in the environment for which it was intended: water.

After a nice airborne visit with the S-92, we steered back to Stafford Regional for a break. Once back, I followed Chad Phillips, a mechanic with Sikorsky’s final production team, as he performed a quick post-flight check of the aircraft.

As Phillips conducted his visual inspection of the titanium main rotor blades, he explained that there were currently about 340,000 hours of flight time on the entire fleet of S-92s produced to date, which was 147 aircraft as of October 2011. The line was sold out through the rest of the year.

“This is the easiest aircraft to maintain,” said Phillips, who was specially selected to travel with N146UK. Most hose fittings, inspection ports and linkages can be seen without mirrors, or having to assume contortionist’s positions. “Everything is really easy to get to,” he said. After our break, I went up with Stacy Sheard, a former Army Black Hawk pilot. Don’t tell Sikorsky, but this was more of a fun flight, since I had concluded the evaluation portion with Vigue. I just wanted a couple more turns around the airport to enjoy the feel of hand-flying the S-92, and practicing with the systems.

“How much is an S-92?” you ask? With all the variations of equipment and contract deals available, Sikorsky was—as would most helicopter manufacturers—reluctant to discuss sticker prices. But my educated guess puts the Legacy ship that I flew in the neighborhood of $20 million. At the end of the day, the Sikorsky S-92 gave a great showing. Interior-space versatility, cockpit design, avionics, and ease of maintenance puts it high on my list of impressive helicopters. I guess the best way to describe it is to say that it flies along with you, as if it’s an extension of your own body and thoughts. And what better compliment can a pilot give an aircraft?

 

 

 

 

 

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