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Monday, October 1, 2007

Operators’ Report: Flying with the Bell 206

Ernie Stephens, With James T. McKenna and Ron Bower

Operators Love It, and Swear By Its Reliability, But Want More Power

THE YEAR 1967 WAS A VINTAGE ONE IN THE rotorcraft world. Not only did it see the birth of this magazine. It also brought us Bell Helicopter’s 206, the light, single-engine helicopter that — with Rotor & Wing — this year marks its 40th anniversary.

The 206 has gone on to become a mainstay of the civil fleet and the introduction for generations of pilots to turbine-powered flight. It is a versatile and reliable workhorse, though somewhat underpowered and cramped. Despite those and other flaws, operators, pilots, and mechanics love the aircraft, as we found in compiling this, the second in our new series of Operators’ Reports on helicopters in the current fleet.

In this report, we review the history and range of the 206 product line, the middle sibling in Bell’s family of light, single-engine turbine helicopters. But we focus on the more powerful and versatile end of that line: the L-series LongRanger aircraft. In compiling this Operators’ Report, we contacted a variety of men and women who own, fly, and maintain the aircraft. We spoke with Bell and vendors that support the 206, and drew on the data of the respected appraisal and consulting firm HeliValue$.

The common thread that ran through every response from the "user community" was that the aircraft they simply refer to as "the L Model" is an excellent, single-engine turbine helicopter. "It’s the Chevy Caprice Classic of helicopters," one pilot said, referring to the sturdy, reliable, 1960s sedan he knew from his younger days. "I love it!"

Yes, like any other machine, it has some bad points, but all in all, the positive comments far exceeded the negative ones. (Some we spoke with needed several minutes to think of anything negative to say about the Bell 206.) Owners, managers, and pilots expressed a sense of loyalty to the manufacturer and the design that has been a part of the aviation world longer than many of the people who fly it have been alive.

The 206 was born of failure. Bell at the start of 1960s was one of three companies selected to compete for a contract to supply a four-seat, turbine light observation helicopter, along with Hiller and Hughes. Its OH-4 design lost to Hughes’ OH-6, but Bell opted to develop a commercial variant. The original design was considered ugly, and Bell reworked it, unveiling a mockup of the 206A at the 1965 National Business Aircraft Assn. annual convention. On Jan. 13, 1967, at the Helicopter Assn. of America annual gathering, Bell delivered the first two production versions of what was named the JetRanger to customers.

(After Hughes submitted a substantially higher bid for a second round of OH-6s, the Army re-bid the contract and selected Bell’s OH-58, based on the 206A. Both the Army and the U.S. Navy later selected the 206 as the basis for their turbine helicopter trainer fleets, as have the militaries of other nations.)

As the JetRanger’s popularity grew, operators sought a higher seating capacity. Bell responded by stretching the cabin 18 in. (You can still see the vertical plug rivets for the insert behind the forward doors, abeam the aft facing seats, in any Long Ranger. The total stretch was 30 in, including a 12-in section in the tail boom.) Bell then added two rear-facing passenger seats and a beefier engine. Designers jokingly referred to the modified 206B as the "long ranger."

The name stuck, and in October 1975 the company delivered its first 206L LongRanger, which became known as the "straight L." It used the same engine as the JetRanger, the 429-shp Allison 250-C20B, and that wasn’t enough for the additional 800 lb it carried. (An option was added for the pilot to squirt a water-alcohol mix — stored in a pressure bottle in the baggage compartment — into the engine on takeoff to keep the turbine outlet temperature lower.)

In 1978, the second LongRanger version (strangely named the 206L-1 LongRanger II) was certified with a 500-shp Allison 250-C28. That engine was plagued by a series of airworthiness directives. In 1981, the third variant (logically named the 206L-3 LongRanger III) was certificated with a still more powerful engine, the 250-C30P. This configuration was and still is a crowd pleaser, with 650-shp from the C30 and the transmission limit remaining at 435 shp. Max gross weight (MGW) stayed the same as in the L-1, at 4,150 lb. The L-3 was in production from 1982 to 1992; Bell delivered more than 600.

In 1992, Bell introduced the 206L-4 LongRanger IV with an identical airframe, but a transmission rated to 490 shp. That allowed an increase in the MGW to 4,450 lb.

Since 1967, Bell has produced more than 4,800 206A/Bs and 1,700 206Ls for civil and military customers, making the 206 arguably the most popular turbine helicopter ever built. Tens of thousands of pilots have flown them over the past three decades.

Of the civil fleet of 4,097, according to Bell, 2,538 were As and Bs, 1,288 were L models, and 271 were AB206s built under license by Agusta. Most are in North America — 2,279, or 55.6 percent. Nearly 13 percent, or 525, are in Western Europe, and roughly 7 percent each in Australasia and South America (290 and 281, respectively). About 5 percent (210) are in Central America, with about 3 percent each in South Africa and the Far East (118 and 116, respectively). The rest are scattered elsewhere.

The 206 fleet has more than 55 million hr flying missions including utility, corporate, emergency medical, offshore, and homeland security. The primary reasons people buy a 206 are "the simplicity of the aircraft, its reliability, its ease of training, as well as the direct operating costs," said Bob Fitzpatrick, Bell’s senior vice president of business development.

Bell today is building the 206B-3 and L-4 at its Canadian plant outside Montreal. It is slated to build 52 this year (26 B-3s, 25 L-4s, and one TH-57 for the Navy). For each of the next two years, it plans to build 46, evenly split between the B-3 and L-4. As far as the order backlog, "right now, we’re in the 2009-2010 timeframe" for delivery slots, Fitzpatrick said.

Operators we spoke with were very satisfied with their LongRangers’ overall performance, with their levels of approval rising with the variant’s number. "It’s the workhorse of our fleet," said Mike Suldo, president of Air Logistics, which operates about 100. "The customers really like it."

Most who have flown both the 206L and the 206B models said the L improves their ability to fly their missions. Jeff LeDonne, a retired lieutenant and pilot for the Maryland State Police, called the L-4 "the best helicopter I’ve ever flown." He also has time in the Robinson Helicopter R22, Eurocopter’s AS365N, and the 206B and 412.

The LongRanger’s best attribute is its reliability. Even with the oldest ships, everyone from owners to mechanics agreed the Ls can be counted on to give a full day’s work without generating a lot of surprises. "It did the job day in and day out," said one high-time former 206L pilot. "They just go and go," said a law enforcement operator.

Likewise, most people we contacted gave the aircraft’s respective powerplants high marks for performance, with the higher Ls rating better. LongRanger operators also seem pleased with the bang they get for their buck. With the L having been on the market since the 1970s, owners have paid a wide variety of sticker prices over the years, but still find the aircraft to be well worth the initial cost and subsequent direct operating costs. Because of the scarcity of good used aircraft and the wait for new ones, some operators today find themselves paying hundreds of thousands dollars more for used aircraft they passed on several years ago, with the aircraft having racked up more hours. That (and the fact that buyers were paying more for used 206Ls than Bell’s list price for new ones) allowed the manufacturer this year to raise its 206L-4 base price 25 percent, to $1.75 million. Used 206L-4s range from $870,000 to $1.575 million, depending on their age, condition, and equipment, according to HeliValue$.

Operators are generally satisfied with Bell’s support of the 206. The most common response was that an operator had never had a problem — the equivalent of everything being just about perfect. "They don’t get me all excited when I call about parts," said one charter and tour operator.

A manufacturer’s response to aircraft-on-ground (AOG) orders plays a major role in how its customer service is perceived. The subject aircraft probably went out of service unexpectedly. The longer it takes to get the needed parts, the longer the aircraft isn’t being productive. That response time is especially critical if the broken aircraft is stranded away from its base. Those happy with Bell’s AOG response said they received everything they needed quickly, overnight in some cases. But LongRanger operators reported mixed feelings about AOG support.

All of the respondents said they are pleased with the quality of both engine parts and technical support they receive from Rolls-Royce. But as with the airframe and dynamics, a small number of customers we spoke with were very unhappy with Rolls’ support.

The L’s flight handling got high marks, with several pilots saying that is the best aspect of the design. The majority of respondents used words like "responsive," "smooth," and "agile" to describe the 206L. One law enforcement operator said the aircraft is docile and "very forgiving."

Those who fly the 206L-4 were particularly happy with its power. Also, the LongRanger flies more smoothly than a JetRanger, due to an improved method of mounting the transmission to the cabin roof. In the JetRanger, the transmission is hard-mounted directly to the roof. Rotor vibrations are transmitted to the airframe. The LongRangers have a nodal-beam absorption system that works like a shock absorber, dampening those vibrations.

As for the cockpit and cabin layout, the positives included a good field of view from the cockpit, as far as tour and executive transport operators were concerned. Items such as upholstery, cockpit layout, and storage areas met with everyone’s approval. One pilot said he frequently spends up to 12 hr a day in his LongRanger, and finds it to be very comfortable.

Regarding maintenance, generally the 206L received good marks, with respondents calling the aircraft "easy to work on."

While the folks we spoke with had no negative comments to share about the LongRanger’s reliability, not even minor ones, the 206 does have its shortcomings.

Most pilots said they wish the "straight L," the L-1, and -3 variants had better high-altitude performance, and a tail rotor that could keep up with high power settings. Several pilots specifically mentioned that the 206L has a harder time than other makes hovering out of ground effect. Those whose duties include hovering and performing steep takeoffs and landings, such as emergency medical services, electronic news-gathering and airborne law enforcement crews, were the most disappointed, saying the aircraft gets "squirrelly" at slow speeds and high power settings with modest to heavy loads. "You don’t want your nose anywhere except in the wind, or you’ll be in trouble," said a pilot who has flown the "straight L," -2 and -3 variants in both police and medevac missions. He feels "the power limitation is actually a tail rotor limitation," referring to the aircraft’s performance charts.

Operators of the L-4 reported no problems in this area. In fact, they gave the L-4, with its -C30P engine, excellent marks for its high-altitude and crosswind-hover manners.

Pilots who fly the L-4 had some concern about flight handling in the thinner air of mountainous regions, which requires substantially more tail rotor authority. Even then, they acknowledged that no helicopter has unlimited power, and the L-4, like any other aircraft, still has to be flown using common sense.

For the few respondents who experienced trouble with customer support, their dissatisfaction was intense. Only one operator cited Bell’s AOG support as the worst aspect of owning the 206L, saying he feels the company has more aircraft in the field than it can support.

The most common engine-support complaint was that it takes too long to get parts. Several operators suspect the U.S. military’s OH-58Ds are getting priority. While they all understand that need, they are frustrated that Rolls, in their view, isn’t making enough parts to go around.

A few operators also complained that Rolls’ engine parts are overpriced. Most of those same operators, however, hold the view that all aircraft parts, regardless of the manufacturer, are overpriced.

One pilot said he was unhappy with the engine’s starting procedure. "Why do you have to modulate the start on an L-model?" he asked. "Why isn’t fadec available?" (Bell only offers a full-authority digital engine controller [fadec] on the 407. However, Pratt & Whitney Canada’s Altair offers an aftermarket fadec-like, computer-controlled start to eliminate hot starts that has been installed by many fleet operators, and also records exceedances like overtorques, or overtemps.

Although the LongRanger received high marks for power, pilots said they are disappointed at not being able to fill all seven seats and their fuels cells and still be able to fly on a summer day. "I wish it had more power," complained an EMS pilot.

Most operators said the cabin configuration is excellent for two passengers and fair for three. With four or adult five passengers, though, the riders are generally miserable. Those in the three forward-facing passengers have to intertwine their legs with those of the aft-facing passengers. "Rearward-facing passengers have to be 5 ft 5 in tall or less to be comfortable," said one executive transport operator.

(In a different take on the cramped cabin, most of the pilots we spoke with who fly the "straight L," -1, and -3 said five-passenger seating comfort isn’t important, because they rarely have the power to fill all the seats and still get airborne.)

EMS crews want more room to work. "Paramedics hate the small cabin," said one EMS pilot.

To accommodate patients, the left, front seatback must be folded down and part of the stretcher protrudes into the cockpit. Medical personnel in the back only have access to half the patient and must keep their supplies and instruments in the limited space that remains in the 80 cu-ft rear cabin.

The cockpit design doesn’t satisfy those who spend a significant amount of time looking through their door windows, like police and sling-load crews. They want a better field of view out to the side, as well as down. While a number of 206Bs and 407s have high-visibility windows made by Bell subsidiary Aeronautical Accessories, but the company doesn’t make them for the L. "We’ve never really had a call for them," said Rick Willis of Aeronautical Accessories. "That’s why we never made any."

How pilots felt about the cockpit seems to hinge on the height of the pilot. Almost across the board, if a pilot said there isn’t enough leg room for the flight crew, he or she stood more than 6 ft tall. If a pilot said the leg room is fine or said nothing at all, that pilot was shorter than 6 ft. (Respondents right at 6 ft split down the middle.) The problem is the bulkhead separating the flight deck from the cabin prevents any rearward adjustment of the front seats.

The biggest maintenance complaint deals with both the 206L’s pair of torsion-tension (TT) straps. Resembling a huge, thick rubber band, the straps hold each main rotor blade to the mast, and must be retired after 1,200 flight hours or 24 calendar months, whichever comes first. Those figures are based on a worst-case scenario of an aircraft flying in a highly corrosive environment. Operators in less corrosive environments are furious over having to bear the high cost of replacing "perfectly good" straps every other year when they seem to have plenty of service left in them.

Until the straps’ life can be increased, LongRanger owners are stuck with a maintenance nightmare requiring 12 hr of labor and replacement of what are often a perfectly good pair of $7,200 straps.

Bell 206L Report Card

Performance C
Reliability A+
Engine Performance A+
Response to AOG Issues B
Flight Handling B
Cabin Comfort/Visibility C
Engine Support B
Aircraft Support A
Maintenance A
Costs B

A Match Made in Missouri

Bell’s LongRanger has done well by this Midwest U.S. company.

If you’re looking for an operator that has staked its entire reputation, as well as its operation, on one kind of helicopter, West Plains, Mo.-based Air Evac Lifeteam is it.

The company’s aircraft of choice: The Bell 206L LongRanger.

Air Evac was started by private citizens who wanted to bring big city-style medevac services to rural areas. It selected the 206 family to carry out that mission and since then, has grown from one aircraft to 62 L-1s and 25 L-3s, making Air Evac the largest LongRanger operator in the world. It also operates a 206B JetRanger and four 407s.

"As a workhorse, the 206L has been really good for us," said Tony Bonham, Air Evac’s chief pilot. "It’s what our company started out with in 1985."

Since its inception, Air Evac has grown into the largest independently-owned and operated, member-supported air ambulance service in the United States, carrying more than 100,000 patients to more than 600 southern and Midwest U.S. medical facilities. The company’s 86 helicopters operate out of its home base in West Plains, Mo, and 63 additional locations in Alabama, Arkansas, Illinois, Indiana, Iowa, Kentucky, Mississippi, Missouri, Oklahoma, Tennessee and Texas.

Bell 206 Performance

  206B3 206L4
Source: HeliValue$, Bell Helicopter
Max speed (Vne) – kt (kph) 122 (226) 130 (241)
Economy cruise speed – kt (kph) at sea level 115 (213) 117 (217)
True average speed, ISA – kt (kph) 116 (215) 118 (218)
Average fuel consumption - lb/hr (kg/hr) 177 (81) 245 (111)
Rate of climb, oblique - fpm (mpm) 1,675 (390) 1,340 (408)
Hover in ground effect ceiling
ISA – ft (m) 13,200 (4,023) 10,000 (3,048)
ISA +20C – ft (m) 10,200 (3,109) 7,700 (2,347)
Hover out of ground effect ceiling, at takeoff power
ISA – ft (m) 5,300 (1,615) 11,200 (3,415)
ISA +20C – ft (m) 3,000 (914) 8,480 (2,585)
Service ceiling – ft (m) at 200 fpm (1 mps) rate of climb 13,500 (4,120) 10,000 (3,048)
Range – nm (km) max fuel, ISA 369 (684) 324 (600)
Range – nm (km) max payload N/A 324 (600)
Specific range, sea level – nm/lb (km/kg) max continuous power, ISA 0.59 (2.43) N/A
Loiter airspeed, kt, ISA 48 (89) 52 (96)
Endurance - Hr 4.9 3.7

TT Straps: Bell’s Achilles Heel

By Ernie Stephens

Bell searches for a better solution to the tension-torsion strap issue.

Every helicopter manufacturer has its own method for keeping the main rotor blades from coming off the mast, while allowing them enough freedom to produce the correct amount of lift at normal operating rpm. For the 206B and L models, Bell uses tension-torsion (TT) straps of a sturdy, elastic material that resemble a pair of elongated rubber bands with reinforced grommets on each end.

Over the course of 11 years and 7 million flight hours, three 206B accidents were attributed to TT strap "separation," a condition in which the component ripped apart under the centrifugal forces of the main rotor. Bell responded by making the straps 1,200-hr life-limited components, instead of the "replace as needed" items they once were. That seemed to be sufficient, until the straps on a Bell 212 with more than 2,100 hr on them — a permissible time for TT straps on that model — failed after 22 months of service.

The common denominator among the three 206B TT strap accidents and the lone 212 separation was material degradation, which Bell engineers tied to the highly corrosive environment in which each of the subject aircraft were operated. In 1980, on the heels of the 212 accident, Bell added a 24-month limitation to the 1,200-hr retirement order, and began searching for ways to coat the straps, or make them from a less corrosion-prone material.

Meanwhile, out in the field, the TT strap issue has had Bell’s customers fuming. "The 24-month interval is way too short," said the owner of six Bells. By 24 months, the average operator has flown less than half the time off of their straps, but still has to throw them away and invest $7,200 in a new pair, plus pay a mechanic to do the 10-12-hr job. Only operators who regularly fly near sand and salt water detect any kind of strap degradation within the 1,200-hr, 24-month retirement time.

"Why can’t aircraft flying in non-corrosive environments be exempt from the 24-month rule?" is the question operators still inundate Bell with.

In 2004, Bell issued a paper entitled "Discussing 206 TT Straps – Again," which re-explained the history of the component’s limitations, and the company’s efforts to extend the retirement times. In it, Bell engineer Don Maguire addressed the issue:

"In aircraft certification terms, it is not possible for different retirement lives to be assigned a given part number contingent upon the operating environment. Therefore, just as in all published retirement lives, the existing 24-month retirement life results from the worst-known case."

Maguire went on to say that their engineers have been working on a solution to the TT strap problem by testing new materials and corrosion-resistant coatings. "The latest design consideration is in field evaluation and uses a steel alloy that is more resistant to fretting corrosion," wrote Maguire in that same document. "Our hope is to achieve at least 36 months of calendar life, and possibly more." But to date, that new design has not received approval.

Bell 206 Weights & Measures

  206A 206B 206B-3 206L 206L-1 206L-3 206L-4
Source: HeliValue$’s The Official Helicopter Blue Book
Weights – lb (kg)
Empty Weight, Standard Aircraft 1,425 (646) 1,598 (725) 1,702 (772) 2,105 (955) 2,200 (998) 2,200 (998) 2,309 (1,047)
Max Gross Weight
Internal Load 3,000 (1,361) 3,200 (1,452) 3,200 (1,452) 4,000 (1,815) 4,150 (1,882) 4,150 (1,882) 4,450 (2,019)
External Load 3,350 (1,520) 3,350 (1,520) 3,350 (1,520) 4,000 (1,814) 4,250 (1,928) 4,250 (1,928) 4,500 (2,041)
Useful Load
No Fuel 1,575 (715) 1,602 (727) 1,498 (679) 1,895 (860) 1,950 (885) 1,950 (885) 2,141 (971)
Full Fuel 1,066 (484) 1,093 (496) 888 (403) 1,238 (562) 1,293 (587) 1,207 (547) 1,398 (634)
External Load 1,575 (715) 1,500 (680) 1,500 (680) 2,000 (907) 2,000 (907) 2,000 (907) 2,000 (907)
Model 250 Variant C18B C20 C20J C20B C28B C30P C30P
Takeoff power - shp (kW) 317 (236) 400 (298) 420 (313) 420 (313) 500 (372) 650 (484) 650 (484)
Max continuous - shp (kW) 270 (201) 346 (258) 400 (298) 400 (298) 489 (364) 557 (415) 557 (415)
Transmission rating
Takeoff -shp (kW) 317 (236) 317 (236) 317 (236) 420 (313) 435 (324) 435 (324) 490 (365)
Max continuous - shp (kW) N/A 270 (201) 270 (201) 370 (275) 370 (275) 370 (275) 370 (275)
Standard 2+3 2+3 2+3 2+2+3 2+2+3 2+2+3 2+2+3
High density 2+3 2+3 2+3 2+2+3 2+2+3 2+2+3 2+2+3
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