FAA Clears Partially Hydrogen-Powered Flight

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The FAA has cleared California-based Universal Hydrogen to fly a Dash-8-300 with one engine powered by hydrogen. The Seattle Times is reporting the aircraft got the FAA clearance on Monday after the company was able to run the engine up to full power. The company is doing its development work at Moses Lake in central Washington State. The company said first flight could occur this month.

Assuming it flies soon, it will be the largest aircraft to date to use hydrogen for part of its power. The engine doesn’t burn hydrogen directly. The hydrogen is used by a fuel cell that generates electricity to run an electric motor that turns the prop. The fuel cell and motor are both in the nacelle. For now, a tank of compressed hydrogen in the fuselage will provide the fuel but the company is also developing liquid hydrogen pods that will allow relatively convenient supply of fuel to the operational aircraft. That system is still in development. The ultimate goal for the system is a retrofit for ATR72 turboprops.

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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22 COMMENTS

  1. Way to go. Hydrogen to drive generators and generators driving electric motors. More deficient and lighter and I would risk to say safer as well. Better than using batteries to drive electric motors. Batteries are still too heavy for aircraft use. Maybe one day when “solid state” batteries be available… Nice to see R&D working hard to achieve “electric flying” to all : )

  2. OK, “relatively convenient supply of fuel” is kind of laughable. Cryogenic liquid that boils away even in the best insulated container. Those vapors are flammable. Severe cryo-burns if you touch any of the equipment. Frost or ice buildup on the equipment. Water when it melts. Hydrogen embrittlement of metals containing it. The same problems for the storage, transportation, and ground handling equipment. It has to be manufactured which takes, drum roll…., fossil fuel energy (either directly or indirectly through manufacturing costs of wind, solar, etc. equipment). So, convenient, really?

    • Right! There is nothing convenient about using hydrogen. Either it is at extremely high pressure (700 bar or 10,000 psi) or it is liquid at just 20 deg C above absolute zero (-253 C or -423 F) and it still has low volumetric density. H2 is a small molecule that leaks thru everything and, as noted, liquid H2 boils off continuously unless it is being actively refrigerated. As it is leaking thru the steel containment vessels, it is also contaminating and embrittling the metal.

    • The parent company is “Universal Hydrogen”, not “Universal Aircraft.” Their core business is focussed on H2 logistics, with swappable, shippable, cryogenic H2 tanks. I have to believe that they are well versed in the known H2 issues.

      Yes, it is a relatively convenient way to use H2, especially when there is virtually no infrastructure involved. More info of interest can be found here:

      aviationweek.com/mro/emerging-technologies/aftermarket-builds-groundwork-hydrogen-electric-retrofits

      • “That system is still in development. The ultimate goal for the system is a retrofit for ATR72 turboprops.” They forgot to include the standard … And the system is projected to be certified by the end of 2024!

    • I would think you’d just need to add appropriate venting at the highest point(s) in the hangar, so that if there was a hydrogen leak, it wouldn’t be able to accumulate at the top of the hangar. (Hydrogen goes up and away when given the opportunity, so long as the hangar was vented properly it shouldn’t be a concern.)

      • Like H2 cars, it’s designed to vent. I think BMW H2 cars specifically tell owners not to park in closed garages because of the need to constantly vent the tank…

  3. Hydrogen fuel cells can be made to work but I actually believe that we will have battery electric planes for commuter and regional flights instead of hydrogen. While hydrogen has a weight advantage, there is nothing easy about using it. The main advantage of battery electric is economic. The projected seat mile cost of battery electric is about 1/4 that of JetA while the cost of “green” hydrogen will probably be more than JetA. You need about 500 to 700 Whr/kg for commuter and shorter regional flights and about 700 to 1000 Whr/kg for most narrow body jet fights (737 or A320 family but something that will look more like Boeing’s braced truss wing proposal) and Lyten has demonstrated 900 Whr/kg with lithium sulfur with 10 to 20 minute recharging. However, I think that SAF will be required for longer flights. I will post some references in a followup posting.

      • This article is someone getting a temporary experimental airworthiness cert under 21.191(a) for an R&D project. Anyone can get one, it’s like getting accepted to community college in that whether or not it’s a big deal or not greatly depends on what’s next. Our company once had one for a C172 exhaust but I guess if we had sent the press release to Avweb, they’d make it out to be a huge accomplishment.

        The first source you point towards is cited by many sources quite frequently, and thankfully the authors completely disclosed their methodology, and I would invite all readers to have a look at its assumptions.

        Their data sources for transport aircraft are listed in detail but consist of several EMB brochures plus some docs provided by Boeing to airport authorities for facility planning. Their .csv data does not derive from these sources so it’s hard to see where they get their numbers, and for no plane I saw do their numbers match the TCDS for the certified aircraft.

        Their math model centers on three airliner classes (RJ, narrow, widebody) but it uses averages that include a crazy range (for instance they average a modern 737-MAX 8 and A321neo with 737-100s and DC9s from 1970s, without weighing the average for which aircraft are currently in service.) A Saab 340 is not performing anything like a E195 obviously

        So these are valid models as far as they go, and they clearly explain their model to support their conclusions, but it is strictly academic. All authors are profs, not aircraft operators. If only integral calculus and brochure metrics were required to make an airplane fly, there would be hundreds of manufacturers. The numbers on paper are just the aero fluid dynamics calc but the real world factors required to meet any certification or operational requirements of 14 CFR are not touched on for either kero or e aircraft and are entirely different. Large inefficiencies exist in both sources but are very different other than wing math. So I have a concern with this being so widely cited as a definitive source on the energy physics of flight.

  4. The world is believing in the biggest fraud in History: that humans are able to modify the climate.
    One day future generations will wonder how could we be so stupid.
    We’re just leaving the Little Ice age and nothing that we do will change it. Furthermore we need MORE not less CO2, the gas of life (photosynthesis) that IS NOT a pollutant.

    • Interesting hypothesis. So, if we need more CO2, and the amount in the atmosphere is already increasing rapidly, there’s obviously no problem. God knows how all those previous generations survived with so little CO2!

    • It’s always funny when “believers” say that heat flows away from cooler space above and down toward a warmer surface below to make the surface warmer.
      But hey, If you can get people to “believe” that the laws of thermodynamics no longer apply then getting them to blame a trace gas is actually the easy part!

  5. The climate argument aside, the hysteria over hydrogen is still rooted in the Hindenburg disaster, which is not really relevant today. NASA and many companies using cryogenic rocket fuels are well versed in handling liquid hydrogen, which is the only really practical method of using it for aircraft purposes. Compressed H2 requires very high pressures and heavy containment tanks, neither of which are desirable for flight. Hydrogen embrittlement is mainly a thing with steel alloys and usually occurs at high pressures and elevated temperatures. Most cryogenic piping and vessels use aluminum alloys for weight considerations. Yes, hydrogen is flammable and will explode if mixed at its ideal stoicometric ratio, but it burns with a low luminance flame that is much less hazardous to humans than gasoline or jet A. Plus, being much lighter than air, hydrogen vapors quickly rise and dissipate from a spill, unlike avgas and jet A that lie in a pool and emit heavy vapors that hug the ground. There is no cleanup from a hydrogen spill since it leaves nothing behind except some frozen vegetation. Other liquid fuel spills require extensive cleanup. And yes, AJ, storing hydrogen fuel tanks inside a hanger is not a good idea, but if I read the article correctly, the fuel pods are removable and can be stored separately in a designated area.

    Producing and handling liquid hydrogen is a known technology that has been around for many years. LH2 requires little more energy than liquid oxygen or LNG. Cryo plants are extremely efficient. The main problem is getting the pure hydrogen in the first place. The so-called ‘green” hydrogen is an advertising ploy since the vast majority of hydrogen comes from fossil fuel refining that consumes energy and emits CO2. I’m not a big proponent of hydrogen over batteries, but battery technology has a long way to go before it has any hope of replacing jet fuel for long-range transportation. Hydrogen may be a practical bridge to the time when batteries are capable of truly replacing fossil fuels.

    • I think you nailed it; Hydrogen has been around a very long time and, in the last 2 centuries of use, it has proven to be only good as a niche fuel. It’s rather a dead-end fuel since it takes more energy to synthesize it that it generates when using it.

      • If you can shift the energy from a solar or wind farm to plug-and-fly tanks that you can actually use on a jet two hundred miles away, why are concerned about using more energy to produce it than it provides when consumed?

        • Because if you divert wind/solar to producing hydrogen for airplanes, then you back fill with oil&coal to power the rest of society. Basically it’s not worth it if the goal is “to reduce carbon”.

          • Wind and solar power have a common problem: being able to potentially generate more power than is needed at times, less at others. Solutions include diverting power to charge batteries, pumping water uphill, etc. The diverted power is power that would not have been generated in the first place.

  6. Making H2 out of fossil fuel is a GOOD THING.

    The United States is RICH in natural resources for oil, several of which have just barely been explored, in Alaska in particular.

    New technology has made more oil accessible and practical to refine in the case of fracking.

    These are good things. We can be energy independent again.

    Personally I don’t see the need for electric airplanes but if we are forced into such a thing HFC would be vastly more appropriate for aviation (and shipping and trucking and maybe cars and motorcycles as well) than batteries.

    On a side note, it appears Moses Lake, just to the north of my home field is a center for electric airplane development. Moses Lake needs something to be proud of lately, maybe this is it and if so good for them.

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