http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=awst&id=news/UH72_111309.xml&headline=Guard Moves To UH-72A Lakota For Medevac
Guard Moves To UH-72A Lakota For Medevac
Nov 13, 2009
Robert Wall/Jeddah, Saudi Arabia
With its modern glass cockpit, twin-engine safety and performance, and reduced noise and vibration, the Eurocopter UH-72A Lakota provides a chance for U.S. Army National Guard units to at last catch up with the advances made in light utility helicopters.
The UH-72A is a commercial off-the-shelf replacement for the venerable UH-1 Huey, performing missions for which the UH-60 Black Hawk is too big or too expensive. Primary missions for the militarized Eurocopter EC145 include medevac, disaster relief, passenger transport and law-enforcement support. More than 200 of the 345 UH-72As to be acquired by the Army will be fielded with Guard units, about 25% of them configured for medevac.
The District of Columbia National Guard’s 121st Medical Company (Air Ambulance) is the first Guard unit to receive aircraft in medevac configuration: six UH-72As replacing nine UH-1H/Vs. Two additional aircraft will be delivered in 2012 to the 1-224th Aviation Battalion (Security and Support), replacing two OH-58s. The aircraft are based at Ft. Belvoir, Va., and will be joined by eight UH-72As of the active Army’s 12th Aviation Battalion in support of the Washington military district.
Training is provided by Eurocopter at its Grand Prairie, Tex., facility, where this Aviation Week pilot, a former Army aviator experienced in the UH-1, had the opportunity to see how the UH-72A compares, flying a company-owned Lakota used as a transition trainer.
A contract for the initial lot of UH-72As was signed in June 2006, with the first aircraft delivered in December of that year. Eurocopter has delivered 85 UH-72As to Army and Guard units, and the first of five for the U.S. Naval Test Pilot School. The 100th aircraft is on the line at American Eurocopter’s Columbus, Miss., facility, where production has reached 55 a year,
All UH-72As are FAA-certified and are military/civil hybrids. Sgt. George Wagner, a crew chief with the 121st, says maintenance personnel training for the UH-72A will graduate with an FAA airframe and powerplant license as well as a military certification. Specialist Lauren Bloch, a flight medic with the 121st, says medical personnel finish training with a basic emergency medical technician certification and are encouraged to become qualified as civilian paramedics.
While the UH-1 carried more payload than the UH‑72A (roughly 4,500 lb. compared with 3,777 lb.), the Lakota’s greater speed and range make up for the difference. Particularly significant for training is its 3.5-hr. endurance, says Maj. Mark Escherich, commanding officer of the 121st.
Frank Kanauka, Eurocopter’s senior pilot for the UH-72A program, pointed out the few exterior differences from the civil EC145 during our walk-around. Most obvious are the nose-mounted wire cutters and extensions on the landing skid: If the helicopter hits a wire below the nose but above the skids, the extensions would direct it below the skids.
The EC145 has optional twin windows in the rear clamshell doors. The UH-72A does not, but in my opinion they would allow more light into the stretcher area for the medic and provide better rearward visibility to the crew chief for confined-area landings.
The main differences are inside the aircraft, the biggest being the number of radios. During disaster-relief operations following Hurricane Katrina in 2005, the Army found its helicopters were unable to communicate with many civilian agencies. As a result, Eurocopter has installed eight VHF, UHF and FM radios in the 400-800-MHz. range for civil support operations, plus one for secure military transmissions. The avionics suite includes Chelton, Garmin and Wulfsberg radios. For operation in civil airspace, redundant Garmin 430s provide communication and GPS navigation.
The system allows the pilot to preprogram three VHF frequencies, an advantage when operating in an area requiring multiple frequency changes over a short period of time, says Lt. Col. Maureen Bellamy, state aviation officer for the D.C. National Guard. “The aircraft’s avionics package allows us to communicate directly with the first responders—law enforcement agencies, fire departments, hospitals and others—something that our old radios did not,” she says.
The redundancy and reliability of the twin Turbomeca Arriel 1E2 engines also are “a significant factor when flying over dense urban areas like the District of Columbia, where safe landing areas are not readily available,” she notes.
While the UH-72A does not have all the “bells and whistles” on civil EC145s, certain niceties can be added as required. These include air conditioners for aircraft in hot areas and engine inlet barrier filters for sandy areas. Some will also have hoist and cargo hooks as required.
The aft cabin, including baggage area, is 4.59 ft. wide by up to 11.23 ft. long, with 50.77 sq. ft. of usable floor space. While the civil version can hold eight seats in a 3-2-3 configuration, the Army will use either two or three rearward-facing seats for medevac or a 3-3 configuration with the seats facing each other for personnel transport. In medevac configuration, two stretchers enter through the clamshell door, sliding along rails that secure them to the floor—a big advance over the UH-1 where stretchers were hung from straps, says Bloch.
The D.C. National Guard is in discussion with Martin-Baker to develop a seat that can slide along the rails where the second stretcher would be, allowing the medic to treat anything from a head injury to a broken ankle while still buckled in. The movable seat will be able to rotate 360 deg. with locking positions every 15 deg.
Entering the cockpit is fairly simple. The cabin floor is just over 3 ft. from the ground, but there is a step running the length of the skid at about 1.5 ft. up. The small cockpit required a bit of gyration to get a leg up and over the cyclic; but once seated, I was comfortable. The seats are adjusted via a lever underneath, much like the Huey. The pedals have pins that pull up, then drop back down into slots once adjusted—rather awkward to do while sitting in the pilot’s seat, so it is best to set it before getting in.
Startup is simple, a matter of flipping the right switches and watching the vehicle and engine multifunction display (VEMD), which includes the first limit indicator (FLI). This is a display with a circular indicator numbered from 0 to 16, the figures representing specific values for torque, turbine outlet temperature and N1 commensurate with atmospheric conditions, Kanauka says. If the needles are at 8.5 FLI, the aircraft is at maximum continuous power and 71% torque or equivalent N1, 10 is 88% torque, while 11 is 91.5%.
As with most glass cockpits in modern helicopters, the FLI does not provide specific data the way the Huey did, but simply lets the pilot know if one of the three parameters is being exceeded. In the UH-72A, a small box will light up beside the errant parameter. Actual percentage figures for the left and right engine parameters are also presented digitally on the respective sides of the circular gauge, color-coded with yellow (caution) and red (alert) tick marks indicating that 10 is the limit for takeoff power, 11 is maximum continuous power with one engine inoperative, and 12 the maximum for 2.5 min. of single-engine operation.
Below the VEMD, on the UH-72A’s central panel is a second liquid-crystal display showing engine and main gearbox parameters. A third panel is the cautions and advisories display, and includes fuel-quantity indication. Each pilot has two larger primary flight and navigation displays. There are also five circular analogue “steam gauges” across the top of the central panel as a backup, including a clock, artificial horizon, rotor/engine rpm., airspeed and altitude.
Picking up to a hover is much like in the Huey, with the right skid coming off first, then the left, then a slight pitch of the nose. And, like the Huey, adjustment to a stabilized hover comes without thinking about it.
I expected the UH-72A to have similar control characteristics to the OH-58, since both are small, “sporty” aircraft. But the Lakota has a heavier control feel more like the Huey, with some force required to move the cyclic. To counter that force in the Huey, I tended to hover with the force trim off. But when I turned off force trim in the Lakota, the aircraft became too sensitive.
Cyclic movement can also be controlled using a “coolie” hat on the stick. But input is slow, so unless you are flying straight and level, it is best to keep force trim on, coolie hat neutralized and accept the force required for cyclic movement.
We were about 800 lb. below the maximum weight of 7,903 lb. with an outside air temperature of 20C at just over 580 ft. MSL, making it a fairly representative flight. I stuck the tail into an 18-20-kt. tailwind; there was plenty of tail-rotor authority and I did not come close to running out of pedal. The aircraft wiggled a bit, but was controllable, with no tendency for the tail to lift as it hovered into the wind.
A normal takeoff with a standard 500-fpm. climb was accomplished pulling only 63% of the maximum 88% torque allowed. If there is any limitation, it will normally be on torque, says Kanauka. A maximum-performance takeoff from a confined area with a 1,700-fpm. climb pulled only 86% torque.
The aircraft will cruise “all day long at maximum cruise speed at 71%,” Kanauka says. I reached 135 kt. at 67% torque and took it to 139 kt., pulling 71% torque, before backing off. Maximum cruise speed is about 140 kt.
One unique characteristic of the aircraft is a variable rotor/engine speed. Standard hover and climb rpm. is 100‑101%. But once the aircraft passes through 55 kt., rpm. automatically drops to 96.5%, reducing noise and fuel consumption. Noise reduction is aided by the hingeless rotor system with monolithic titanium hub, all of which combine to produce a noise level 6.7 dBa. below International Civil Aviation Organization limits, says Eurocopter.
The aircraft is also relatively vibration free, even lacking the traditional pronounced shudder as it passed through translational lift. Bloch says the low vibration in the aft cabin allows easy and accurate setting of intravenous injections into veins during flight, something that was difficult, if not impossible, in the back of a Huey.
Another advantage was demonstrated by a confined-area approach to a small tree-covered island in Joe Pool Lake just south of Grand Prairie. The aircraft is only 42.65 ft. from main-rotor to tail-rotor tip with blades turning, compared with roughly 57 ft. for the Huey. This small footprint, plus reduced rotor wash, “clearly makes operations safer and easier at hospital helipads and anywhere else where the landing zone is small,” Bellamy says. Small size also allows for rapid transportability, with up to five UH-72As fitting into a C-17, two with blades removed and three with blades folded.
The aircraft is not intended for combat and is restricted to domestic operations, although some are to be delivered to Puerto Rico, Germany and Kwajalein in the Pacific. Deployment to low-threat environments such as Kosovo and Serbia is under discussion. The Army has established training standards for tactical flying to include nap-of-the-earth operations, but Escherich says not enough data have been compiled on the impact on component wear.
The aircraft is almost totally automatic, both for navigation and flight control as well as for instrument approaches, with dual Sagem autopilots and Garmin GPS auto-approach. One of the dual GPS systems is coupled to the autopilot to provide auto-navigation. Operation is essentially “dial-in,” with the pilot simply entering the settings and letting the aircraft do the work.
Escherich says pilots used to flying legacy aircraft such as the UH-1 need to learn to manage the reduced workload provided by the UH-72A’s coupled navigation and control systems. Whereas in the Huey, pilots are constantly flying the aircraft, in the Lakota everything is so automatic that pilots could become lax and “have to be more cognizant of the cockpit requirements,” he says. But this reduced workload allows the pilot to focus more on decision-making, “and in my opinion has greatly increased the willingness and confidence of our pilots to file and fly [in instrument meteorological conditions].”
The aircraft’s full automatic stabilization also allows hands-off flight and, to some extent, hovering, although its hover hold is not as stable as in the AH-64 Apache.
Versus the UH-1, the UH-72A is a sports car compared to a family sedan. On my first approach, I turned base to final and began reducing airspeed and altitude. Reaching 60 kt., I looked outside to check the approach angle, looked back inside and was doing 90 kt. Kanauka says the aircraft is “very speedy,” with the tendency to approach too fast, causing new pilots to have to make a big flare at the end.
The airspeed display has a “tendency indicator” that moves up or down from the actual airspeed indicator, letting the pilot know where speed will be within 5 sec. if not corrected. This allows the pilot to adjust the cyclic accordingly, although I initially tried to chase the line rather than make a correction and hold it—a rookie mistake.
Finally, as a former Huey pilot who has sat for an eternity just waiting for the rotor blades to stop turning, I particularly liked one other feature on the UH-72A—a rotor brake.
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par Poncho (Admin) Jeu 30 Juil 2009 - 23:03EADS North America
