SkyWest Airlines will have to adjust the speed and altitude of some of its aircraft, after the Federal Aviation Administration says one of the airline’s planes stalled during descent last April.

According to the FAA, a flight from Denver to Oklahoma City rapidly descended from 39,000 feet to 27,000 feet, reports ABC News (warning: link has video that autoplays). The plane was able to land without incident at its scheduled destination, the FAA notes.

The new restrictions will require SkyWest’s CRJ700 planes to stay below 35,000 feet and its 900 line of aircraft to a limit of 33,000 feet. That way, as the FAA sees it, SkyWest pilots will have a larger margin for error.

The FAA also slapped cruising speed requirements on airline: SkyWest’s CRJ200s must cruise at a minimum of 272mph, while CRJ700s and 900s must be going about 288mph while cruising.

Minor mistakes at higher altitudes can cause jets to lose lift and stall, while slow speeds can also initiate a stall.

“A stall happens when the airflow over the wing is interrupted, and basically you stop flying for a period of time,” explains ABC Aviation consultant John Nance. “You have to take action immediately, and if you mishandle it you can end up in an even worse situation.”

SkyWest said the FAA’s restrictions amount to a “head-scratcher” that was “a sweeping and arbitrary reaction that was not fully explained.” Besides, the airline says, the plane didn’t stall at all. Instead, it experienced a “slow speed event.”

“Months ago, one SkyWest CRJ aircraft experienced an isolated slow speed event, which is when an aircraft reaches less than optimal speeds. The aircraft’s slow speed alert systems functioned perfectly, and the crew responded appropriately with a 4,000-foot descent. No stall occurred,” SkyWest said in a statement to ABC.

“We expect that when the FAA fully analyzes the data, it will lift all restrictions,” the airline added. “SkyWest is an industry leader in safety and is committed to ensuring each of our flights operates safely.”

After Plane Stalls Mid-Flight, FAA Slaps SkyWest with Altitude, Speed Restrictions [SkyWest]

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