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IFR Fix: Nice story, and a quizIFR Fix: Nice story, and a quiz

I was hiking up a road through an apple orchard in the foothills of the White Mountains when two Fairchild Republic A–10 “Warthogs” thundered fast and low overhead.

Photo by Mike Fizer.

My companion was startled at the commotion on what had been a day of peace and serenity. Not me; as a chart check later confirmed, multiple military training routes pass above the spot.

End of nice story. Now for the quiz: What do the designations of those MTRs (VR840, 841, and 842) tell you about their nature?

VR signifies a visual route. IR is for instruments. Designations reveal altitudes of use: A three-digit route number means at least one route segment has one or more segments above 1,500 feet agl. A four-digit MTR has no segments above 1,500 feet agl—including instrument routes.

Visual MTRs have weather requirements: According to the Aeronautical Information Manual, operations “are conducted in accordance with VFR except flight visibility must be 5 miles or more; and flights must not be conducted below a ceiling of less than 3,000 feet AGL.”

IR operations “are conducted in accordance with IFR regardless of weather conditions.”

If those details didn’t come readily to mind, an AOPA survey of pilots’ awareness of special-use airspace revealed low knowledge of MTRs. Most pilots don’t check MTR activity status despite MTR lengths and high-speed, low-altitude traffic.

At least MTRs are charted; ALTRVs are not.


The survey suggests that more than 70 percent of instrument pilots are grouped as having never heard of ALTRVs, or as “not at all familiar” with them. Congratulations if by reading that sentence you moved from the first group to the second.

ALTRV stands for altitude reservation, or “airspace utilization under prescribed conditions normally employed for the mass movement of aircraft or other special user requirements which cannot otherwise be accomplished. ALTRVs are approved by the appropriate FAA facility.” Several recent ALTRVs were for military missile launches.

Pilots who check notices to airmen carefully will be seeing more ALTRVs, says Rune Duke, AOPA’s expert on all things airspace, because the FAA’s need to segregate airspace for commercial space launches and other special requirements is growing.

Is that why you got that long, unexplained vector on your last instrument flight?

Could be. Recently Duke spot-checked ALTRV notams to see how much of the activity that most IFR pilots have never heard of was going on.

“Right now there are 12 ALTRVs all over the country,” he said.

Dan Namowitz

Dan Namowitz

Associate Editor Web
Associate Editor Web Dan Namowitz has been writing for AOPA in a variety of capacities since 1991. He has been a flight instructor since 1990 and is a 30-year AOPA member.
Topics: Navigation, Instrument Rating, IFR

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