2024 Corporate Aviation Leadership Summit

A Piper M Series aircraft being used by ZeroAvia as a flying testbed for its hydrogen propulsion system crashed on April 29 last year after electrical power was lost to both of its motors, according to a report by the UK’s Air Accident Investigation Branch (AAIB). The report found that an emergency procedure to clear an inverter lockout proved&nbsp;ineffective and that the company had failed to investigate&nbsp;previous loss-of-power incidents also caused by inverter lockouts that had happened three flights prior to the accident near Cranfield Airport in England.
In their summary of factors contributing to the non-fatal accident, in which the aircraft was badly damaged after a crash landing in a field, AAIB investigators said that ZeroAvia’s flight test team did not review the risk assessment of the testing following the loss of propulsion on two previous flights. “Ad hoc changes were made to the flight test plan, including the position where the electrical power source was switched, without the knowledge of the competent person,” they concluded.
The report was published as ZeroAvia prepares&nbsp;to make the first test flight of its fuel cell-based powertrain on a larger <a href="https://www.futureflight.aero/news-article/2022-05-06/zeroavia-converts-second-dornier-228-hydrogen-propulsion-flight-testing">Dornier 228 aircraft </a>from its UK base at Kemble. It expects that&nbsp;to happen on July 15, subject to the UK Civil Aviation Authority (CAA) issuing a permit to fly. The Piper flight tests had been conducted under the agency’s experimental rules.
ZeroAvia said it welcomed the conclusion of the investigation and that&nbsp;“many of the issues identified in the report were similarly noted in our internal investigation and have been addressed robustly.” The flight testing last year was conducted as part of the HyFlyer 1 project, which received UK government funding.
“We have embedded key learnings into both our organizational culture and structure, as well as our future technical designs,” the California-based start-up said in a written statement. “This includes the establishment of a Safety and Security Review Board, adding to our team with extensively qualified members in several critical positions, including our design, airworthiness, and flight test teams, and establishing a safety management system based on a ‘just’ aviation culture, including occurrence reporting, investigation, and corrective actions functions.” 
The AAIB report stated that the Piper lost power when, as part of the testing process, the pilots switched off the battery with the intention of leaving the electrical motors solely powered by the hydrogen fuel cell. “During this interruption, the windmilling propeller generated a voltage high enough to operate the inverter protection system, which locked out the power to the motors,” it stated. “The pilot and observer were unable to reset the system.”
As part of the accident report, the<a href="https://assets.publishing.service.gov.uk/media/62a20c39d3bf7f037097be7b/Piper_PS-46-350P__Modified__G-HYZA_08-22.pdf"> AAIB</a> has made five safety recommendations for changes to the CAA’s rules on the operation of experimental aircraft. They include changes to the design and positioning of aircraft controls and displays, as well as calling for closer attention to0&nbsp;the scope of flight testing and the ability of the appointed competent person to safely manage the operations.
Under its HyFlyer 2 project, ZeroAvia is working to secure a supplemental type certificate to convert a regional airliner to hydrogen propulsion and have it ready to enter commercial service by the end of 2024. The company, which has yet to confirm which type it will seek to bring to market first, is considering plans to convert aircraft such as the Cessna Grand Caravan and the Twin Otter. It also aims to provide propulsion for new aircraft including Otto Aviation's planned Celera 750L.
In the longer term, ZeroAvia believes, it could also convert larger 40-seat aircraft and it has received support from operators including British Airways, <a href="https://www.futureflight.aero/news-article/2021-12-13/united-airlines-signs-investor-and-customer-zeroavias-hydrogen-conversion">United Airlines</a>, and Alaska Airlines. It is also working with <a href="https://www.futureflight.aero/news-article/2021-10-26/mitsubishi-and-alaska-air-back-zeroavias-plans-hydrogen-airliners">Mitsubishi</a> on plans to convert regional jetliners&nbsp;such as the CRJ family.
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Managing Editor

Charles Alcock

Hydrogen Flight Crash Report Highlights Faults in ZeroAvia's Test Process

Monte Aircraft Leasing has agreed to buy 100 ZeroAvia ZA600 powerplants as part of an agreement to provide aircraft leasing and financing instruments for operators that run zero-emission flights. Under the deal, ZeroAvia will install the hydrogen fuel cell powertrains on existing and new Cessna Caravan, DHC-6 Twin Otter, Dornier 228, and HAL-228 regional turboprops. 
ZeroAvia and London-based Monte aim to retrofit the aircraft for clients starting in 2024 and provide and finance maintenance and hydrogen availability services to support the operations. The deal will make ZeroAvia Monte’s exclusive hydrogen-electric powertrain provider for the aircraft in its portfolio. However, the company has not yet explained how it intends to source aircraft for conversion and on what terms they will be offered to airlines.
The 600kw ZA600 powertrain—designed to support five- to 20-seat airframes—uses gaseous hydrogen stored onboard in lightweight tanks. The hydrogen feeds fuel cell stacks that generate power by converting hydrogen into electricity. 
ZeroAvia plans to soon flight test the ZA600 powertrain in a retrofitted Dornier 228. In the initial testing configuration, the aircraft testbed will fly with one hydrogen-electric powertrain on one wing, while keeping the stock engine on the other wing to ensure safe testing conditions. The testing program will then sequentially move to full hydrogen-electric flight, ultimately working toward a certifiable hydrogen-electric powertrain as the sole propulsion source for the categories of airframes included in the deal. 
ZeroAvia’s work to develop ZA600 to a certifiable configuration forms part of the HyFlyer II project, in part supported by the UK government through the ATI program. The company says its plans are&nbsp;“well advanced” to certify the ZA600 powertrain for entry into service in 2024. 
The U.S. company also has begun work on the ZA2000, a two-&nbsp;to five-MW modular powertrain meant for certification in 40- to 80-seat turboprops by 2026. The ZA2000RJ powertrain will expand that technology to regional jets as early as the late 2020s, said ZeroAvia.
During the last quarter of 2021, ZeroAvia secured partnerships and funding with Alaska Air Group and United Airlines to accelerate the development of its ZA2000 engine. Another customer for the conversion program to hydrogen power is leasing group <a href="https://www.futureflight.aero/news-article/2021-11-09/leasing-group-rose-cay-and-irish-cargo-carrier-back-zeroavia-plans-hydrogen">Rose Cay</a>.
Late last month ZeroAvia expanded an agreement that calls for Mitsubishi’s MHI RJ Aviation Group (MHIRJ) to provide engineering services and aircraft integration to support the certification of the ZA2000RJ. The agreement followed a memorandum of understanding signed&nbsp;last October&nbsp;that outlined the MHI subsidiary’s contribution of engineering for certification of the engines to FAA Part 33 rules and advisory services to evaluate the feasibility of a green retrofit program for regional aircraft.
The announcement with MHIRJ follows ZeroAvia's recent expansion of its Hollister location in California and a deal with Shell for hydrogen supply, as well as the opening of a facility at Paine Field in Washington state in January.

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Hydrogen Flight Crash Report Highlights Faults in ZeroAvia's Test Process

ZeroAvia and Monte Aircraft Leasing To Retrofit 100 Aircraft with ZA600 Powerplants

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