H55 Demonstrates High-Density Altitude Electric Flight in Colorado, Showcasing Aircraft Performance in Extreme Conditions

Switzerland & USA–H55, the electric aviation pioneerborn from the Solar Impulse project,has completed a series of high–density altitude,high–temperature demonstration flights in Colorado as part of itsAcross USATour.These testsconfirmthereal–worldperformanceoftheH55poweredBristellB23Energic,illustratingtheoperational performance of electric aviation.

Operating in ChallengingConditions

The Colorado mission flights took place from an airfield situated at 5,800 feet above sea level, withtemperatures reaching 36°C (96.8°F) and a takeoff density altitude of 9,500ft.The B23 Energicperformed flawlessly providing smooth, 500 feet per minute climbs using normal runway distance fordepartures.This “hot and high”scenario tests an aircraft’s take–off distance, climb performance, andoverallefficiency.Incontrasttoconventionalcombustionengineswhichfacedegradedperformanceinsuch operating environments, the electric propulsion system of the B23 Energic delivered steady andreliable results.

“Colorado offers one of the most demanding environments for aviation,”said Gregory Blatt, Co–Founder and Mission Director of H55.“This stop gives us a chance to demonstrate how electricpropulsionisnotonlysustainable,butoperationallyconsistentinconditionspreviouslyconsideredrestrictiveformanyaircrafttypes.We’reespeciallygratefultoCentennialAirportandjetCentersofColorado for their warm welcome and support.Their commitment to innovation and sustainabilityreflects the shared mission of accelerating the adoption of clean aviation solutions.”

AFirstforColorado

CentennialFlyers,aleadingflightschoolbasedatCentennialAirport(KAPA),signedaLetterofIntent(LOI) during H55’s Colorado stop–over, becoming the first operator in the State to formally committo adopting electric aviation.Their decision reflects the growing momentum across the U.S.for theBristellB23Energic,whichcontinuestoattractinterestfromflightschools,pilotindividuals,operators,and regional airports seeking sustainable and cost–efficient training solutions.This engagementfurther strengthens H55’s expanding order book and underscores the market’s readiness for certifiedelectric aircraft.

ProvingElectricFlightinRealEnvironmentalSettings

Electricpropulsionsystems faceheightened scrutinywhen testedoutside ofcontrolledenvironments.In Colorado’s hot, high–altitude climate, H55’s certified Electric Propulsion System (EPS) excels,maintaining optimal performance despite the challenges posed by both elevated temperatures andreducedairdensity.Thesystemdeliveredconsistentclimbratesanddemonstratedefficientbatterycooling,provingthatelectricflightcanoperateeffectivelyindiverseclimatesandgeographiesyear–round.

KeyQuestionsAnsweredinColorado

Canelectricaircraftoperateeffectivelyathigh–densityaltitudes?Yes—theB23Energicperformedinconditionsof36°C(96.8°F)anda9,500ftdensityaltitudewithstability and strong climb rates, at 500 feet per minute.Howdoesheataffectelectricpropulsion?H55’sbatteryandEPSarchitectureperformedwithinnominalthermallimits,withnosignsofdegradation despite high ambient temperatures, up to 40°C (104°F).

AdvancingClimateResilientFlightTraining

As electric aircraft join training fleets, climate resilient performance is essential.The B23 Energicofferszeroemissions,lownoise,andminimalvibration—idealforflightschoolsandairportsunderstricter environmental rules.Colorado illustrated flawless performance in conditions that normallystrain conventional aircraft.With no performance loss or system degradation, H55’s EPS proveselectric propulsion is ready for high–altitude, high–temperature flight.

NextStop:Oshkosh

Following the Colorado tour stop, the Across USATour continues with its seventh stop at EAAAirVentureOshkosh2025—“TheWorld’sGreatestAviationCelebration”.Attendeescanlearnmoreaboutthefutureofelectricaviationatthe2025ElectricAircraftSymposium(July19–20),followedbytheannualairshow(July21–27)—afirstforbothH55andBristellBRMAERO.ABristell/H55pressconferencewill be held onTuesday, July 22 at 11:00 AM CST at Booths 296–297.

AboutH55H55 is a Swiss–based company founded by the former Solar Impulse management team:AndréBorschberg,SebastienDemont,andGregoryBlatt.Dedicatedtorevolutionizingtheaviationindustry,H55 provides certified electric propulsion and battery management systems tailored to a diverserange of aircraft, aiming to achieve sustainable air travel.H55 supplies certified electric propulsionsystems with full airplane integration solutions for general aviation and regional transport aircraft.Through its pioneering legacy and commitment to certified solutions, H55’s team of visionaryengineersandaerospaceexpertsareattheforefrontofdrivingtheaviationindustrysettingnewstandards and pushing the boundaries of electric aviation.

Source: H55Photo. Credit: H55