The Embraer 175 aircraft that made its debut at the Aspen-Pitkin County Airport (ASE) in early December is about to become the main aircraft that United will operate there this summer. That is an outcome that was previously doubted by some observers, but the aircraft has gone through extensive testing and upgrades to operate at ASE and overcome the airport’s challenging conditions.
The final United Express CRJ700 flight from ASE was previously scheduled for May 4 at 12:55 p.m., heading to Chicago. The airport will then be closed until the evening of June 1 for runway repairs. When the airport reopens, all but a handful of United flights will be on the E175, with the final CRJ flight now scheduled for late July. “This will mark the end of an era following 19 years of safe and reliable CRJ700 service for United Express at ASE,” air service consultant Bill Tomcich wrote in his Fly Aspen Snowmass newsletter in February.
United began phasing out the CRJ700 over the winter season. Since Feb. 13, all daily United flights to Denver and two of the three daily flights to both Los Angeles and San Francisco have used the E175. Starting this summer, only American Airlines and Delta Air Lines, which also fly to the Aspen airport, will continue exclusively using the CRJ700. Flights for all three commercial carriers serving Aspen are operated by SkyWest Airlines.
An Embraer promotional video called “E175 in Aspen | Flight Test Campaign,” released Jan. 31, showcases extensive flight engineering and testing that went into preparing the E175 for operations at ASE. The flight test took place at Gunnison airport in February 2024 and consisted of several takeoffs and several go-arounds.
“This new engine model was specifically developed to meet a customer’s needs in Aspen, which is a relatively high-altitude and low-temperature airport,” Rogerio Kiyoshi Makita, a propulsion system engineer at the Brazilian aircraft manufacturer, said in the video.
Summer performance
The arrival of the first commercial flight to Aspen on an E175 on Dec. 3 was lauded as a milestone in the community’s air service. The plane, with its 94-foot wingspan, fits the existing airfield; incorporates modern technology that is expected to improve reliability; and features a more comfortable cabin with expanded first-class seating and larger overhead bins.
But prospects for the E175 serving as a viable year-round replacement for the CRJ700, the only aircraft that operated commercially at ASE until Dec. 3, had previously been dimmed by the plane’s heavier weight. A workgroup that studied various aircraft types’ suitability for Aspen concluded in 2019 that the E175 had “marginal” summer missed-approach capability and would probably be subject to a significant weight penalty. That’s due to Aspen airfield’s nearly 8,000-foot elevation, which, combined with summer heat, makes the thin air even thinner and hampers aircraft performance — a concept known as “density altitude.”
Although the E175 flight test in winter conditions in Gunnison was successful, Embraer’s announcements about the E175 don’t explicitly address the density altitude issue in the summer, and the manufacturer did not respond to questions from Aspen Journalism. But upgrades to the aircraft are apparently encouraging enough for United to remove the CRJ700 from its summer schedule.
Thiago Cazarine, airline marketing manager at Embraer, explained in the promotional video that Embraer brought two main improvements to the aircraft, including adding more thrust capability to the engine and adapting the landing and takeoff speeds. Both changes increase the aircraft’s performance to help it overcome the Aspen airport’s challenging conditions.
“The E175 engines are some of the quietest and most efficient in the industry, yet have the software upgrades necessary to provide [1% to 3%] more thrust for Aspen’s unique geography,” SkyWest spokesperson Marissa Snow wrote to Aspen Journalism. “Before every flight, we closely monitor weather such as wind speed and temperature and make any adjustments needed with safety as our top priority.”
Tomcich told Aspen Journalism via email that he would be surprised if the E175 does not face weight restrictions during the summer months — just as nearly all aircraft, including the CRJ700, do in the summer at ASE. The CRJ700 operated for the first 10-14 years of its operations at ASE with several restrictions. “It wasn’t until 2018 when SkyWest started operating afternoon nonstop flights to [Dallas] and [Chicago] for American during the heat of the summer afternoons, and those flights are still weight restricted to this day to carry a limited number of passengers,” he said.
One way airlines work around that issue is scheduling flights in the morning, late afternoon or early evening, when temperatures are cooler. “We really won’t know exactly how the E175 performs from ASE [in the summer] until they actually start operating. But … they seem to be performing better than expected so far,” Tomcich wrote.
A growing fleet of ‘Aspen ready’ planes
Tomcich on Feb. 20 told the Airport Advisory Board that the upgraded E175 has been exceeding expectations and performing better out of Aspen than the nonupgraded E175 out of Eagle “because of the engine upgrade but also because they were conservative on all of their estimates.”
Snow confirmed that operations have gone well and customer feedback has been exceptional.
Perhaps the most significant early clue that Embraer believed it could bring the E175 to Aspen came in October 2023 when SkyWest and United Airlines announced a $1.1 billion deal to purchase 19 new E175s to be delivered by the end of 2026 in a plan to convert the CRJ700 into CRJ550s that would serve markets smaller than Aspen. The existing routes served by the CRJ700 will be replaced with the E175.
According to Tomcich’s comments to the Airport Advisory Board, SkyWest and United now have nine “Aspen ready” E175s – including five 10-year-old aircraft that have received special modifications and new engines and have been fully refurbished – and four new planes that were delivered in mid-December. SkyWest expects seven new E175s to be delivered this year as part of the 2023 purchase agreement. All will receive what officials are calling the “Aspen upgrade.” By the end of 2026, SkyWest will have 25 Aspen-capable E175s, including 19 new planes and six upgraded aircraft.
“This is definitely more E175s than are needed for ASE only. But this unique subfleet of ‘performance 175s’ will likely be useful for United in quite a number of airports other than ASE,” Tomcich wrote to Aspen Journalism, adding that some of the nine upgraded E175s are already flying to the Gunnison, Sun Valley and Bishop airports. “I expect other mountain airports, including Jackson Hole (JAC) and Vail/Eagle (EGE), will likely benefit from these higher-performing aircraft, as well.”
According to Tomcich’s comments to the board, there have been instances where the E175 was able to land when the CRJ700 had to divert, and one case where the E175 had to go back to Denver while the CRJ700 was able to make its approach. “So, there will be cases where the weather conditions are more favorable for one aircraft than the other, but it looks like the E175 so far is just very slightly more reliable because of the lower minimums, but it’s not like a game-changer yet.”
What about noise and pollution?
Although the E175 may improve the airport’s reliability, it won’t help the county meet its community goals that call for a 30% reduction in both emissions and noise. That is because the E175 burns about the same amount of fuel and is noisier than the CRJ700.
“I am told that the enhanced thrust only kicks in when the throttles are pushed all the way forward. So for the vast majority of situations including on approach, these engines do not produce any more noise than they typically would,” Tomcich wrote to Aspen Journalism, adding that although the CRJ700 and the E175 are powered by nearly identical engines, the acoustics may sound different because the engine is mounted on the wing instead of the tail.
The two aircraft approach the airport differently, according to Tomcich, who lives in the Fryingpan Valley under the flight path. He has observed that the E175’s landing approach is lower in elevation and faster than the CRJ700, which results in a shorter-lived but noisier approach. During takeoff, the Embraer aircraft may get louder initially with the increase in thrust, but the noise is also short-lived because the E175 can climb more rapidly than the CRJ700.
As more E175 flights are being scheduled, the airport is getting ready. Former Aspen-Pitkin County Airport Director Dan Bartholomew said at the Jan. 16 Airport Advisory Board meeting that the airport will convert two additional spots during the spring closure to accommodate both the E175 and the CRJ700, and will purchase two additional passenger ramps for the E175. When the airport reopens on the evening of June 1, six of the eight gates will have dual parking positions that can accommodate both aircraft. Two will remain exclusively used for the CRJ700.
Skywest recently announced in its Q4 earnings call that American Airlines has extended its contract with the CRJ700 to “close to the end of the decade,” suggesting that the CRJ700 won’t be making its final approach to Aspen just yet.
Editor’s note: This story was updated to reflect that United updated its summer schedule in May to add in a handful of CRJ700 flights through July; the airline’s summer schedule previously did not include any CRJ700 flights.
This story was published on the front page of the May 3, 2025 edition of Aspen Daily News.