Mentor Matters: Revisiting Personal Minimums

The argument goes that to pass an instrument rating (let alone type rating) checkride, the pilot is required to demonstrate the ability to fly an approach all the way down to published minimums. Therefore, if months later a pilot isn’t confident in his or her ability to safely do so, the pilot should self-ground until he or she has regained the proficiency needed to competently fly in any legal weather conditions and execute an ILS down to a 200-foot ceiling and 1,800-foot runway visual range (RVR). According to this philosophy, using personal minimums above those of the published approach is a “crutch” of sorts, allowing a nonproficient pilot to continue flying while wrapped in an illusion of safety.

As a mentor pilot, I’ve always found this type of binary thinking (i.e., you can either fly to minimums on any given day or you self-ground) deeply flawed and counter to a realistic plan for maximizing safety. Yes, pilots absolutely should aspire to being able, any day of the week, to safely fly a precision approach to a 200-foot decision height without superhuman effort or, worse, frightening themselves. And yes, if they can honestly say this ability has slipped, they should at the earliest possible time get together with an instructor or experienced safety pilot, and—in controlled circumstances—practice until the rust is off.

Yet there’s a big difference between having the ability to fly an approach to minimums safely and choosing to expose oneself regularly to the associated risk, particularly when relatively inexperienced or when other circumstances are aligned against the pilot. The FAA itself recognizes this in its regulation of for-hire operations conducted under FAR parts 121 (airline) and 135 (charter). In both, when a captain is new to the left seat of a particular aircraft, the pilot faces company-mandated raised approach minimums until he or she has accumulated 100 hours as pilot in command. Even though this restriction is not required to be observed by FAR Part 91 operators, many professional flight departments incorporate such a rule into their operations manual.

There’s a big difference between being able to fly an approach to minimums safely and choosing to expose oneself regularly to the associated risk.These operations manuals embody the concept that the FAA, in the construction of Part 91, gives operators of private flights extensive latitude in deciding how they will conduct their flights—in many cases allowing operations that may not be considered prudent by some. Takeoff under Part 91, for example, is allowed no matter how low the visibility, and regardless of whether the pilot has received training that simulates very low-visibility takeoffs. Contrast this with parts 121 and 135, where the PIC receives extensive simulator training in low-visibility takeoffs, and must take into account runway lighting and visibility reporting equipment before determining if takeoff is allowed.

A little consideration reveals a few other areas in which a careful pilot may want to consider imposing “personal minimums” that are more conservative than required by Part 91:

Commencing an approach. In much of the world even a private operator cannot begin an approach unless the visibility is reported to be at or above what’s prescribed. Yet in the United States, the FAA allows Part 91 fliers to “look and see.” Consider that if we do that on a precision approach, we’d often be deliberately bringing an aircraft to within 200 feet of terrain—in instrument meteorological conditions (IMC)—with an expectation that we cannot legally transition from the approach to landing. That’s questionable thinking in most cases.

Duty time. Under Part 91, an owner-pilot can legally work a 12-hour day at the office, drive to the airport, and act as solo pilot on an all-night coast-to-coast flight. In contrast, for-hire operators face complex restrictions on both how long a pilot can be on duty, as well as how much time can be spent in the air. A reasonable starting point for a Part 91 operator might be to limit flight time to eight hours when single pilot, or 10 hours if operating as part of a two-pilot crew. Time “on duty” could be restricted to 14 hours, with duty being anything of a work nature, whether related to flying or not. It’s worth keeping in mind that after being awake for 17 hours, pilots have been found to perform flying tasks as if they’d just rapidly consumed three alcoholic beverages. Worst of all, it’s nearly impossible for a pilot to accurately self-assess fatigue level.

Landing runway length. This is easily the riskiest area in which a Part 91 pilot might strictly follow the “letter of the law.” If the aircraft flight manual (AFM) of a light jet publishes information that for a given weight, altitude, and temperature (WAT) condition, the aircraft will need 3,000 feet of runway for landing, the pilot is perfectly legal landing at a runway with exactly that length. But considering that runway overruns are the most common type of accident encountered by jets, prudent operators often make sure they land with a defined safety factor of 25 percent to 100 percent beyond the AFM-required landing distance available.

Circle-to-land procedures. Many for-hire operators have shied away from conducting any circling approaches in weather below legal visual meteorological conditions (VMC) of a 1,000-foot ceiling and three-statute-mile visibility. Given that circling procedures are often visual maneuvers conducted in IMC, these procedures have been the set-ups for countless loss-of-control accidents, and it’s not hard to see why.

Neil Singer is a Master CFI with more than 8,500 hours in 15 years of flying.