Commercial, Safety

Airbus Looks to Reinforce Crash-Resistant Fuel System to Pass Drop Test

By Frank Wolfe | May 15, 2019
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Airbus has been offering its crash-resistant fuel system for the H125 since 2014 (Airbus photo)

Helicopter industry observers said that Airbus' push for full European and U.S. certification of the company's crash-resistant fuel system (CRFS) for its H125, AS350 B3, and EC130 B4 helicopters in all types of helicopter operations has hit a snag. A sling hook used for utility, firefighting, cargo transport and other operations, has punctured the system during Airbus testing this year.

Federal Aviation Administration (FAA) regulations in 14 CFR 27.952, established in 1994, govern the requirements for commercial CRFS, including filling the fuel tank at least 80 percent with water and no water leakage from the tank after being dropped from a height of at least 50 feet.

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"An underbelly installation might obviously  influence the crash resistance of the CRFS during a drop test, as it is located below the fuel system like in any other helicopter," Airbus said on May 13 in written response to questions from Rotor & Wing International. "We are currently looking at the necessary reinforcements, if any, that will allow our CRFS solution to pass the required drop test. Compliance with 27.952, including underbelly installation, is expected in early 2020."

"Underbelly installations are used by many H125 customers for a wide range of missions, including aerial work , utility, cargo transportation missions, Bambi bucket [for firefighting] etc.," Airbus added. "Obtaining 27.952 underbelly certification requires a specific drop test with a cargo swing configuration, which is what we are doing now."

In 2014, Airbus began offering its CRFS after the FAA certified it for the H125 (AS350 B3e) helicopters with the exception of operations with underbelly installations.

"The certification of our CRFS solution will be extended in 2020 to include the AS350 B3e with underbelly operations as well as the AS350 B3 and EC130 B4 with underbelly operations as well," Airbus said.

Of the 984 H125s delivered by Airbus, 190 have the Airbus CRFS, the company said.

"Equipping an aircraft with a CRFS adds additional weight, which thus would affect the payload and performance of the aircraft," Airbus said. "The H125 offers no power compensation for the extra empty weight of the new CRFS (unlike the H130). Therefore, many customers have elected to retain the original fuel system in order to preserve the helicopter’s original payload, especially for aerial work operations."

Airbus has said it is offering its CRFS for the H125 at cost for $44,000, and the company points to operator concerns that installations of other CRFS, such as those by StandardAero and Robertson Fuel Systems, can cost between $100,000 and $120,000, excluding labor.

As Airbus seeks European Aviation Safety Agency and FAA certification of its CRFS for some 1,500 AS350 B3s and 400 EC130 B4s — both certified before 1994, some 55 AS350 B3s and 50 EC130 B4s have an FAA and EASA-certified CRFS by StandardAero and Robertson Fuel Systems, the latter companies said.

In addition, "Airbus will not be creating a retrofit fit kit for [AS350] B2, BA, B1, B and D models," according to StandardAero and Robertson Fuel Systems. "Those are only available under the Robertson/StandardAero STC [supplemental type certificate]."

"The Robertson/StandardAero CRFS is vastly different than the CRFS Airbus is planning to certify," StandardAero and Robertson Fuel Systems said. "The proven, robust durability, aircraft adaptability, ease of installation and peace of mind our solution delivers to operators is commensurate with the cost. The Robertson/StandardAero CRFS passed the most stringent FAA requirements, with added safety measures like cargo swing compliance (added safety for underbelly installations), and is fielded and approved to fly around the world on virtually all AS350 variants."

The FAA Re-Authorization Act of 2018, P.L. 115-254, requires all newly-manufactured helicopters, including those type certified before 1994, to have crash-resistant fuel systems, and the FAA said it is working with industry to help helicopter companies comply with the legislation.

Part 44737 of the law gives helicopter manufacturers until April 5 next year to comply with the inclusion of the systems on all newly-built helicopters and stipulates that the FAA administrator “will expedite the certification and validation of United States and foreign type designs and retrofit kits that improve fuel system crash-worthiness; and not later than 180 days after the date of enactment of this section, and periodically thereafter, issue a bulletin to inform rotorcraft owners and operators of available modifications to improve fuel system crash-worthiness; and urge that such modifications be installed as soon as practicable.”

The move toward outfitting commercial helicopters with CRFS gained significant impetus after a July 2015 crash of a Flight for Life AS350 helicopter air ambulance in Frisco, Colo. The crash killed the pilot, Patrick Mahany, seriously injured one flight nurse, and severely disfigured Dave Repsher, another flight nurse. Last year, Airbus and Air Methods Corp. reached a $100 million settlement with Repsher’s family. Karen Mahany, the widow of Patrick Mahany, was a forceful advocate for the CRFS provisions in the FAA Re-Authorization Act.

Last year, the FAA Rotorcraft Occupant Protection Working Group (ROPWG) — formed in November, 2015 after the Frisco, Colorado, crash and chaired by crash worthiness expert Dennis Shanahan — advised the FAA to require retrofits within three to five years on all helicopters, including those type certified before 1994.

"I think we dropped the ball a little on that one," said Shanahan, a former U.S. Army flight surgeon and commander of the Army Aeromedical Research Laboratory. "I wish we had recommended time frames more firmly, but the FAA told us that just writing a rule was a three-year process. If I had known what Congress was doing, I think I would have recommended a specific time frame."

The ROPWG also advised the FAA to require upper-torso restraints on all helicopters and proper restraints for all passengers, including children.

"We have not heard back from the FAA," Shanahan said. "As far as we know, the FAA has done nothing on our recommendations."

Some safety observers are concerned that the FAA reauthorization law does not require CRFS retrofits. For its part, the National Transportation Safety Board (NTSB) has recommended that the FAA mandate crash-resistant fuel systems for all civil rotorcraft. Such systems have been in place on U.S. military rotorcraft for decades.

“The FAA Aircraft Certification Service reviewed the ROPWG’s recommendations for newly manufactured and existing fleet rotorcraft, and is developing a plan to address them,” the agency said earlier this year. “In the interim, the FAA is working with companies to help them meet the requirements of the 2018 FAA Reauthorization Act.”

Last December, the FAA updated Special Airworthiness Information Bulletin, SW-17-31R1, to notify all registered helicopter owners and operators of helicopter models that fully or partially meet Part 27 and 29 CRFS standards.

Those helicopter models that have CRFS solutions that fully comply with the FAA standards include the Airbus EC120 B, EC130 T2, EC135, the MBB-BK 117 C-2, MBB-BK 117 D-2, the EC130 B4, and AS350 Bs, the Bell 427, 429, and 505, the Helicopteres Guimbal CABRI G2, the Leonardo A109 S, AB139 and AW139, AW169, AW189, the MDHI 600N, the Robinson Helicopters’ R66, and the Sikorsky S-92A.

The Bell 407 is partially complaint with the CRFS standards, according to the FAA.

Airbus and Sikorsky have not wholly agreed with the ROPWG that advised the FAA to require retrofits within five years. Airbus said the FAA should “strongly recommend, rather than require,” the installation of crash-resistant fuel bladders meeting the 50 foot drop test and 250 pound puncture resistance requirements, while Sikorsky said the working group “has not demonstrated the basis of the recommendation to retrofit CRFS into Part 29 aircraft” and that the company “would rather the [working group] recommend, not require, CRFS be retrofitted in Part 29 Transport Category aircraft.”

Sikorsky, which has estimated that a CRFS could reduce the S-76's range by 37 percent, did not respond to a request for comment on CRFS solutions the company has developed for commercial rotorcraft.

Since the 1994 FAA regulations mandating CRFS on commercial helicopters certified after 1994, "so little has been done," Shanahan said. "It's almost unconscionable that so little has been done. It's not that expensive. Most OEMs want it."

"A lot of lives have been lost over the past 25 to 30 years that could have been prevented if these [CRFS] standards had been implemented earlier," he said.

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