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What's happening: Shares of Air Methods (NASDAQ:AIRM), a provider of air medical emergency transportation services within the U.S., were grounded today and fell as much as 21% after the company provided an update on its third-quarter earnings expectations after the closing bell last night.

Why it's happening: According to Air Methods' third-quarter update, preliminary revenue per community-based transport fell ever-so-slightly to $11,972 compared to $11,988 in the year-ago period. Air Methods blamed the modest dip on a decrease in privately insured patients as a percentage of transports to 32.6% from 34.2% in the year-ago period.

In addition, though community-based patient transports increased by 7% to 15,789 from the prior-year period, patients transported for community bases in operation greater than one year declined by 3%, or an estimated 375 transports (consider this figure the equivalent of a retailer reporting same-store sales). As such, Air Methods now expects to report EPS in the range of $0.83 to $0.87 for the quarter compared to the CapitalIQ consensus EPS estimate of $1.07.

As Air Methods CEO Aaron Todd noted, "Quarterly fluctuations in flight volumes and net reimbursement per transport are not unusual for Air Methods; having both of these factors reflecting weakness in a third quarter is less typical. Air Methods has instituted a supplemental price increase of 3% effective October 1st to help offset these variables moving forward."

Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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