IFR Fix: The extra airspeed exception
You’ve added several knots to your aircraft’s Category B approach airspeed for the rime icing on your wings. Now you add a few more for wind shear on final. That leaves you flying a Category B-certified aircraft at a Category C airspeed on an approach without published Category C minimums.
Can you continue?
All instrument pilots learn about aircraft approach speed categories A through E that determine the ceiling-and-visibility minimums to apply when flying instrument approaches. Most general aviation pilots fly aircraft certified in Category A (zero to 90 knots) or Category B (91 to 120 knots). The speeds are based on the aircraft’s published VREF, or 1.3 VSO at the maximum certified landing weight, which never changes.
But operating conditions do change. Instrument pilots also learn that when an aircraft certified in one approach-speed category must use an out-of-category speed—perhaps to compensate for icing or gusty winds—the higher category’s minimums apply. (If higher category minimums were not authorized, neither was your approach.)
Under the new AIM guidance, it is permissible to fly the approach at an airspeed higher than the range of your aircraft’s category and still use the aircraft’s certified airspeed category minimums. That is, a Category B aircraft can fly an approach at Category C speed and use Category B minimums.
But doing this raises special risks, notes Rune Duke, AOPA senior director of airspace, air traffic, and aviation security.
For one thing, approach-procedure designs are based on the highest speed for a category. Maneuvering at a higher airspeed could put you outside a circling approach protected area, the FAA noted in a presentation.
Then there’s the job of landing from a faster-than-normal approach. “Runway length, obstacle and landing distance calculations must be considered,” the FAA added.
The extra leeway pilots are granted to cope with these rather drastic scenarios following the revision of AIM paragraph 5-4-7 comes with several other caveats.
The FAA continues to encourage pilots to “apply higher minimums as a proven best practice.”
And it reminds pilots that another strategy to consider as an alternative to operating at higher speed in “non-normal” conditions is to land on a different runway—or at a different airport.
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