If your aircraft belongs to Category A, should you invariably adhere to using those minimums?
Aircraft Approach Category Certification
According to FAR 97.3, an aircraft’s approach category is determined based on a published speed known as Vref. This is the approximate speed for conducting a stabilized final approach. In the case where Vref is not specified for an airplane (which is the norm for most light aircraft), Vref equals 1.3 times Vso, which is the stalling speed of the aircraft in a landing configuration.
Each approach category corresponds to the minimums that you will find at the bottom of an instrument approach:
Selecting Minimums Based on Your Actual Final Approach Speed
Just because your airplane is certified as “Category A” doesn’t mean that you should always utilize Category A approach minimums. As per AIM 5-4-7 (b), if it becomes necessary to fly at a speed faster than the aircraft’s published category, the minimums for the higher category should be employed. The paragraph explains “As an additional example, a Category A airplane (or helicopter) that is operating at 130 knots on a straight-in approach should utilize the approach Category C minimums.”
- Example 1 (Cessna 172 Skyhawk, Category A): If you fly the final approach segment at 95 knots (indicated), you should use Category B minimums.
- Example 2 (Cirrus SR-22, Category A): If you fly the final approach segment at 125 knots (indicated), you should use Category C minimums.
Sometimes, the minimums do not change across categories, as is the case with the ILS shown below.
In previous years, the AIM suggested that pilots choose straight-in minimums based on the certified approach category of the aircraft being flown. However, that is no longer the case.
Currently, it is all based on your indicated airspeed during flight (whether circling or straight-in). This update makes perfect sense, as higher minimums provide a greater safety margin when you are flying at a high speed.
What do you think? Let us know in the comments below.
