The Return of Single-Engine IFR Helicopters

Jen Boyer 2020 Winter

Cover Photo

The IFR-capable Bell 407 GXi is available in models suitable for US military training as well as civilian purchase.

Peter Handley/Bell Photo

Bell and Leonardo bring IFR-capable aircraft to market.

This past summer, our industry welcomed back an old friend, one that hadn’t been seen in the US market since 1999: the single-engine helicopter certificated for flight under IFR conditions (SE-IFR). In July 2019, Leonardo received an FAA supplemental type certificate (STC) for the first SE-IFR helicopter in more than two decades, the TH-119. Less than a month later, Bell received an STC for its 407 GXi to operate under instrument flight rules.

It’s no coincidence that both of these exciting new entrants arrived so recently. These first certifications are the culmination of decades of work behind the scenes, in both technology and regulation. The paths the two manufacturers took to certification, however, are vastly different.

SE-IFR: A History

To truly understand the SE-IFR issue, it’s important to understand how we got here.

Helicopter flight rules for instrument conditions made their first appearance in the 1970s. At the time, single-engine rotorcraft conducted IFR flights regularly, well before the advent of GPS, glass cockpits, and digital autopilot systems. The rules these helicopters were certificated under, found in Appendix B of 14 CFR Part 27, Airworthiness Standards: Normal Category Rotorcraft, hadn’t changed significantly since the early 1980s.

In 1999, the FAA issued AC 27-1B, Certification of Normal Category Rotorcraft. This document, which was a total revision of AC 27-1A, issued in 1997, dictated the extinction of SE-IFR rotorcraft.

AC 27-1B in essence incorporated into Part 27 numerical safety analysis methods as a way of determining OEM compliance in meeting safety standards. The advisory circular (AC) required helicopter manufacturers to prove that critical aircraft systems had an “extremely improbable” failure rate of one in 1 billion. In other words, OEMs had to demonstrate that these systems would incur only one failure in 1 billion hours of runtime. Any critical onboard system that couldn’t meet this failure rate was required to be duplicated, with redundancy providing an additional safety margin.

Overnight, single-engine IFR helicopters became cost and weight prohibitive.

In 2003, AC-1B was revised again, raising the bar even higher. This time, the AC defined loss of function of attitude, airspeed, or barometric altitude instruments, or conditions that would cause those instruments to issue hazardously misleading readings, as individually “catastrophic” when operating in instrument conditions. Industry interpretation of this change was that triple-redundant systems would now be required.

At the same time the 2003 AC was issued, Part 23 single-­engine airplane manufacturers received relief from these new requirements: SE-IFR airplanes were required to meet a probability of one in 1 million before being subject to duplicate systems. In response, new aircraft came on the scene, like the Cirrus SR-series, that deployed the latest GPS, glass cockpits, and autopilot technology. This relief wasn’t extended to the helicopter industry, however, in part because the latter was still a long way off from meeting even this lower probability requirement.

“There are several reasons why regulation changes for small light airplanes couldn’t be extended to helicopters at the time,” says Harold Summers, director of flight operations and technical services at HAI. “Helicopters aren’t inherently stable like airplanes. There also was a great deal of work needed to prove that the aircraft could be safely flown in IFR conditions without all the redundancies. The advanced, lighter technology for helicopters hadn’t yet caught up.”

Industry Asks for Change

In 2015, with support from partner associations, the helicopter industry petitioned the FAA to consider reducing certification barriers for SE-IFR helicopters. In the 16 years since the publication of AC 27-1B, a number of important technologies, including WAAS (wide area augmentation systems), GPS, cell phones, tablets, and flight planning apps, had been introduced, all available in affordable, lightweight, consumer-­friendly packages. The industry was finally in a position to meet the same one in 1 million standard as light airplanes.

In the summer of 2015, HAI, AHS International (rebranded in 2018 as the Vertical Flight Society, or VFS), the General Aviation Manufacturers Association, and the Aircraft Electronics Association published the 14 CFR 27 Single-Engine IFR Certification Proposal, an association and industry white paper (bit.ly/SE-IFR). The proposal explicitly linked improving helicopter safety to facilitating an economically viable certification plan for SE-IFR helicopters and expanding IFR operations.

The paper referenced worldwide helicopter accidents related to flights in marginal VFR (MVFR) and inadvertent entry into instrument meteorological conditions (IIMC). The authors argued that more accidents (194), and resulting fatalities (326), occurred from 2001 to 2013 from pilots being ill-equipped for MVFR and IIMC conditions than would have occurred from the expected failure rates of SE-IFR helicopter systems.

“The lack of SE-IFR helicopters developed a dangerous culture in our industry,” explains Paul Schaaf, former HAI vice president of operations and the HAI lead for the white paper. “Pilots needed to get their instrument rating to get a job, but very few used it again if they flew single-engine operations. Few companies kept their pilots’ instrument skills strong. Add to that the pressures to get the job done if there’s any chance of VFR, and it’s a recipe for disaster. 

“We argued that the probability of IIMC and controlled flight into terrain was higher than any probability of equipment failure,” Schaaf continues. “By allowing SE-IFR helicopters, we could save lives.”

The white paper addressed six key concerns with the FAA’s certification standards for SE-IFR helicopters:

  • Use one in 1 million as the failure rate that would require redundant systems in lighter SE helicopters rather than the original FAA standard rate of one in 1 billion
  • Allow generic high-intensity radiated field (HIRF) testing based on established construction techniques (ambiguities in the then-current Part 27 language required testing on a case-by-case basis each time a new piece of equipment was added)
  • Allow a single hydraulic system when aircraft can be shown through rigorous testing to be flyable without hydraulics
  • Reduce the requirement for three navigation communication systems to two
  • Reduce the requirement for dual pitot–static systems to one
  • Allow a battery to be considered as a second electrical generation system.

In 2017, the FAA released policy statement PS-ASW-27-15, Safety Continuum for Part 27 Normal Category Rotorcraft Systems and Equipment, which adopted some of the processes and concepts recommended in the white paper. With the publication of the Safety Continuum, the FAA officially recognized that safety and risk must be balanced across a wide spectrum of aircraft and operations, specifically calling out aircraft weight and propulsion type, whether passengers are flown for hire, and societal expectations as major factors in airworthiness decisions. 

The FAA saw the Safety Continuum as a way to “facilitate a more rapid incorporation of advances in technology for systems and equipment by recognizing a balanced approach between the risk and safety benefits [of] installing such technology.”

Through the FAA’s Safety Continuum process, helicopter manufacturers received relief in failure probabilities and can now request waivers from the AC 27-1B requirements by submitting issue papers. After close review, the FAA can decide whether to issue the waivers.

Leonardo's TH-119 in July 2019 became the first SE-IFR helicopter in 20 years to be approved for production. Specs: max cruise speed: 131 kts; max range: 515 nm (1,516 lbs of usable fuel, no reserve fuel, at 5,000 ft); useful load: 2,756 lbs; seating: 6/7

Leonardo Photo

Two Paths to Certification

Despite all the changes in certification brought about by the FAA’s policy revisions, the world’s first SE-IFR helicopter approved for production in 20 years, the Leonardo TH-119, was certificated using the 1999 AC 27-1B standards. 

Leonardo’s history gave it an advantage. The TH-119 was designed to meet a customer’s request in the early 2000s for a skid-equipped, single-engine version of the twin-engine AW109. The master plan for the TH-119 included a second generator, dual hydraulics, a second pitot-static system, and a three-axis automatic flight control system with dual stage.

Leonardo didn’t need to design an SE-IFR helicopter from scratch; the company just needed a customer to justify the expense of taking an aircraft through the certification process. Enter the US Navy and its call for the TH-73, a new SE-IFR training helicopter and the catalyst for the US certification of the first two SE-IFR helicopters in 20 years.

“When we submitted the TH-119 for IFR certification, it met the original FAR 27 with no waivers,” says Andy Gappy, Leonardo TH-119 campaign manager. “We had actually been working on it for quite some time. When the US Navy canceled the TH-57 program in 2012, we started looking at our aircraft and identified the 119. We could have certified it years ago, but the holdback was technology and the customer. We were waiting on what specifically the navy required, pacing ourselves with the navy, and developing the project over four years to meet their requirements.”

Leonardo described its certification process with the FAA as seamless, with the OEM working with the agency throughout design and certification. “Having the FAA involved every step of the way helped a lot. They’ll give you recommendations for tweaks, and that can be very helpful,” Gappy says.

Leonardo’s resulting STC for SE-IFR makes the TH-119 available to the civil industry, as well, as both a new helicopter and a retrofit. Leonardo has since seen considerable interest from customers seeking both versions.

Bell took a slightly different tack in its bid for the TH-73 contract. Building its SE-IFR helicopter off the design for the single-engine 407, the maker sought relief from the FAA in two areas: dual hydraulics and HIRF susceptibility. After considerable testing and documentation, the OEM received waivers for both.

“We’re overall very happy with the outcome and pleased with the FAA’s involvement,” says Eric Sinusas, Bell’s program director for light aircraft.

“The Safety Continuum has potentially strengthened safety,” adds John Bouma, Bell’s director of civil certification. “I hope that making safety technologies easier to certify, accessible, and less expensive to install overall will significantly increase safety. It’s an excellent example of bridging regulation with advanced technology.”

Like Leonardo’s TH-119, the IFR-capable Bell 407 GXi is available for civilian purchase as both a new aircraft and a retrofit kit, with more concrete time lines and details to be unveiled at HAI HELI-EXPO 2020. Bell reports customer interest is very strong.

Other OEM Plans for SE-IFR

While not developing directly for the US Navy contract, other manufacturers are looking at how they can exploit the new market niche. Kurt Robinson, president of Robinson Helicopter Co., says the manufacturer is looking to add an SE-IFR–capable aircraft to its line of small, affordable helicopters. “We’re excited about this direction and think it’s very much in the realm of possibilities at Robinson in the next three to five years,” says Robinson.

At MD Helicopters, Steve Suttles, vice president, military/commercial sales and marketing, says SE-IFR isn’t a “must-have” feature for the majority of commercial utility or general flight operations. “Based on our research and experience, our commercial operators with a significant IFR requirement are better and more affordably served with a light twin-engine aircraft, like the IFR-capable MD 902,” says Suttles. “That said, MD Helicopters is certainly interested in offering IFR capability in our sought-after single-engine aircraft, should that capability be required by a qualified fleet customer.”

Kopter Group’s clean-sheet design, the SH09, is ideally positioned for SE-IFR, and the manufacturer plans to market it as such, says Cecile Vion-Lanctuit, head of communications and marketing for the OEM. The aircraft’s baseline version includes the Garmin G3000H integrated flight deck and offers standard safety and redundancy features typical of FAA Part 29 rotorcraft, such as dual hydraulic and electrical systems, easing the development of the IFR-optional kit.

New Challenges

After a 20-year absence, SE-IFR helicopters are once again available in the US market. Their return is certainly a win for the industry and the FAA. The industry submitted concerns, and the FAA listened, eventually developing a policy that allowed for a more nuanced approach to aircraft certification. Best of all, operators and pilots now have more, safer choices of aircraft to fly.

Yet there are still issues to overcome for our industry to take full advantage of the safety benefits of SE-IFR flight.

“IFR is paramount to safety, especially with fully capable IFR aircraft. Now that the industry has access to this tool again on a more affordable level, the industry must embrace it,” says Tom Judge, executive director of LifeFlight of Maine, chair of the US Helicopter Safety Team Infrastructure Work Group, and former chair of the Association of Air Medical Services board. “The fixed-wing world is 20 years ahead of the helicopter world in terms of IFR flight, and if the helicopter world is going to survive, it needs to catch up.”

Industry experts argue that the key to success is full industry acceptance of, and even preference for, IFR operations, from training to operator policy. Having an IFR-capable aircraft does no good if the pilot isn’t IFR rated, current, and confident.

“The industry needs to embrace IFR and ensure pilots are trained, current, and proficient to take full advantage of this technology and save lives,” says VFS Executive Director Mike Hirschberg. “Dual-engine IFR aircraft crash today because pilots aren’t comfortable with IFR and so choose to fly VFR and lose.”

The US National Airspace System will also require transformation to accommodate helicopter IFR operations. IFR helicopters have been such a small piece of overall traffic, they currently fly airplane routes (though the FAA and ICAO are currently designing and implementing IFR helicopter-only routes; see “File IFR and Fly TK Routes,” Fall 2019 ROTOR, bit.ly/FlyTKRoutes). There are considerable opportunities to develop helicopter IFR routes that permit more aircraft, especially with increased drone and air taxi traffic on the horizon.

“In New York, for example, the FAA shoehorns helicopters into the airplane system, and they can get quite the runaround in those crowded routes,” Schaaf says. “The industry and FAA can work together to develop low-level helicopter IFR routes there and around the country to allow for increased helicopter IFR traffic. ADS-B allows more aircraft to fly with decreased workload for the pilot.

“The technology is here, and now [so is] the aircraft,” Schaaf continues. “There’s a great opportunity for the industry to participate in creating a usable IFR system to support our aircraft.”

As SE-IFR aircraft move the industry toward increased IFR operations, the industry is sure to experience change and growing pains. “Our hope is that in 10 years, the whole industry culture has changed where SE-IFR is natural and filing IFR or requesting a pop-up clearance when the weather deteriorates is second nature,” says Hirschberg. “No one will feel the pressure to push it in marginal VFR, and we’ll experience a significant increase in safety as a result.”

HAI’s Summers echoes that sentiment. “This is a great example of cross-industry collaboration and the FAA’s willingness to work with us on a solution. It will be interesting to see how it evolves. Single-engine IFR isn’t going to be an instantaneous success. The industry needs to be committed to supporting IFR operations and the required training; otherwise, we won’t see the safety results we want.”

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