Getting the Maximum from Personal Minimums
Story and photos by Susan Parson
Reprinted with permission from FAA
Aviation News Magazine
don't have to be involved in aviation very long before you hear the time-honored
advice on personal minimums. It goes something like this: 'Legal weather
minimums are just a starting point. You should establish your own personal
minimums for flying, and you must have the discipline to stick to them'no matter
how much you want to make the trip.'
familiar? It's good advice. Most pilots would agree that it's a good idea, and
it's probably true that more accident pilots'not to mention their innocent
passengers'might be alive today if they had followed it. So why didn't they? And
why do so many pilots who appear for flight reviews or other training look
sheepish and make excuses for why they haven't managed to write down their own
are probably many reasons that the concept of personal minimums is more honored
as an idea than as a regular practice. I suspect,
however, that a major reason is that many pilots'even safety-conscious
ones'don't have a clear idea about where to start, and that many flight
instructors'even conscientious ones'may not know how to guide pilots through the
process of establishing personal minimums. I confess that I have been guilty on
both counts. I consider myself to be a safety-minded pilot, but for too many
years my personal minimums were little more than a vague mental notion. I also
like to think of myself as a conscientious and safety-minded flight instructor
(CFI), but far too few of my clients would be able to tell you that I even
talked about, much less taught about, personal minimums. To make amends, here
are some ideas that might help fellow aviators avoid similar sins of omission.
Let's start with
the basics. What exactly do we mean when we talk about 'personal minimums?' In
formal terms, personal minimums refer to an individual pilot's set of procedures,
rules, criteria, and guidelines for deciding whether, and under what conditions,
to operate (or continue operating) in the National Airspace System.
this definition is accurate, there are several reasons why you may not find it
particularly helpful as a starting point. First, it tends to describe the
product rather than explain the process, which is where many pilots have
trouble. Second, and more importantly, the formal definition of the end
product'your personal set of procedures, rules, criteria, and guidelines'does
not really convey one of the core concepts: personal minimums as a 'safety
buffer' between the demands of the situation and the extent of your skills.
of personal minimums as the human factors equivalent of reserve fuel. When you
plan a flight, the regulations require you to calculate fuel use in a way that
leaves a certain minimum amount of fuel in the tanks when you land at your
destination or your alternative. The reserve fuel is intended to provide a
safety buffer between fuel required for normal flight and fuel available to
avoid total quiet in your engine compartment.
the same way, personal minimums should be set so as to provide a solid safety
buffer between the skills required for the specific flight you want to make, and
the skills available to you through training, experience, currency, and
proficiency. In fuel calculations, you wouldn't dream of planning a flight that
would force you to use your reserve fuel, or (worse) take you to the 'unusable
fuel' level in the tanks. In skill calculations, you shouldn't consider making a
flight that requires use of skills at the 'reserve' or (worse) 'unusable fuel'
level of your piloting ability.
where do you start in developing personal minimums? There is no single 'right'
way to proceed, but if you're unsure of how to proceed in establishing your own
personal minimums, this method offers a reasonable place to start.
Step 1 - Review Weather
people think of personal minimums primarily in terms of weather conditions, so
begin with a quick review of weather definitions. The regulations define weather
flight conditions for visual flight rules (VFR) and instrument flight rules (IFR)
in terms of specific values for ceiling and visibility.
our purpose, we will define IFR as a ceiling less than 1,000 feet AGL and/or
visibility less than three miles. LIFR is a sub-category of IFR. VFR is defined
as ceiling greater than 3,000 feet AGL and visibility greater than five miles.
MVFR is a sub-category of VFR.
Step 2 - Assess Your
Experience and Comfort Level
first glance, this part of the process might look a bit complicated, but please
bear with me. It might take a few minutes to review, record, and summarize your
personal experience, but I think you will find that the finished product is well
worth your time. First, think back through your flight training and complete the
'Certification Training, and Experience Summary' chart on the next page. The
Certification, Training, and Experience Summary Source are adapted from the
FAA's Personal and Weather Risk Assessment Guide (October 2003). It can
be found at:
http://www.faa.gov/education_research/training/fits/guidance/media/Pers Wx Risk
think through your recent flying experiences and make a note of the lowest
weather conditions that you have comfortably experienced as a pilot in your VFR
and, if applicable, IFR flying in the last six to 12 months. You might want to
use the charts below as a guide for this assessment, but don't feel that you
need to fill in every square. In fact, you may not have, or even need, an entry
for every category. For example, suppose that most of your flying takes place in
a part of the country where clear skies and visibilities of 30 plus miles are
normal. Your entry might specify the lowest VFR ceiling as 7,000, and the lowest
visibility as 15 miles. You may have never experienced MVFR conditions at all,
so you would leave those boxes blank.
In my part of the country, normal
summer flying often involves hazy conditions, but over relatively flat terrain
knows the local terrain and, since I have
regularly operated in hazy daytime MVFR conditions (e.g., 2,500 and four miles),
I would use the MVFR column to record these values. Even in my home airspace,
though, I would not consider flying down to VFR minimums at night'much less in
the range of conditions defined as MVFR. For night VFR, I would not be
comfortable with anything less than a ceiling of at least 5,000, and visibility
of at least seven to eight miles. How my entries would look in the Experience &
'Comfort Level' Assessment VFR & MFR chart:
you fly IFR, the next part of the exercise is to record the lowest IFR
conditions that you have comfortably, recently and regularly experienced in your
flying career. Again, be honest in your assessment. Although I have successfully
flown in low IFR (LIFR) conditions-'down to a 300 foot ceiling and 3/4 mile
visibility'I would never claim to have been 'comfortable' in these conditions,
especially since I was operating in a single pilot/single engine configuration.
I would therefore leave the LIFR boxes blank, and my entries for known 'comfort
level' in Instrument Meteorological Conditions (IMC) would be as shown below:
If I combine my
entries into a single chart, the summary of my personal known 'comfort level'
for VFR, MVFR, IFR, and LIFR weather conditions is as follows:
Step 3 - Consider Other
Ceiling and visibility are the most obvious conditions to consider in setting
personal minimums, but it is also a good idea to have personal minimums for wind
and turbulence. As with ceiling and visibility, the goal in this step is to
record the most challenging wind conditions you have comfortably experienced in
the last six to 12 months'not necessarily the most challenging wind conditions
you have managed to survive without bending an airplane. As shown in the chart
to the right, you can record these values for category and class, for specific
make and model, or perhaps both.
In addition to winds, your 'comfort
level' inventory should also include factors related to aircraft performance.
are many variables, but start by completing the chart with reference to the
aircraft and terrain most typical for the kind of flying you do most. Remember
that you want to establish a safety buffer, so be honest with yourself. If you
have never operated to/from a runway shorter than 5,000 feet, the 'shortest
runway' box should say 5,000 feet. We will talk more about safe ways to extend
personal minimums a bit later. (See chart on the right.)
Step 4 - Assemble and Evaluate
Now you have some useful numbers to
use in establishing baseline personal minimums. Combining these numbers the
Baseline Personal Minimums chart on the next page shows how the whole picture
Step 5 - Adjust for Specific Conditions
flight you make involves almost infinite combinations of pilot skill,
experience, condition, and proficiency; aircraft equipment and performance;
environmental conditions; and external influences. Both individually and in
combination, these factors can compress the safety buffer provided by your
baseline personal minimums. Consequently, you need a practical way to adjust
your baseline personal minimums to accommodate specific conditions.
that the suggested adjustment factors are just that'a suggestion. If your flying
experience is limited or if you don't fly very often, you might want to double
these values. In addition, if your situation involves more than one special
condition from the chart above, you will probably want to add the adjustment
factor for each one. For example, suppose you are planning a night cross-country
to an unfamiliar airport, departing after a full workday. If you decide to make
this trip'or you might decide that it is safest to wait until the next day'this
chart suggests that you should at least raise your baseline personal minimums by
adding 1,000 feet to your ceiling value; one mile to visibility, and 1,000 feet
to required runway length. How about adjustments in the other direction? Some
pilots fear that establishing personal minimums is a once and-for-all exercise.
With time and experience, though, you can
modify personal minimums to match growing skill and judgment. When you have
comfortably flown to your baseline personal minimums for several months, you
might want to sit down and assess whether, and how, to safely push the envelope.
If, for instance, your personal minimums call for daytime visibility of at least
five miles, and you have developed some solid experience flying in those
conditions, you might consider lowering the visibility value to four miles for
your next flight.
- First, never
adjust personal minimums to a lower value for a specific flight. The time to
consider adjustments is when you are not under any pressure to fly, and when you
have the time and objectivity to think honestly about your skill, performance,
and comfort level during last the few flights. Changing personal minimums 'on
the fly' defeats the purpose of having them in the first place.
- Second, keep all other variables constant. For example, if your goal is to lower
your baseline personal minimums for visibility, don't try to lower the ceiling,
wind, or other values at the same time. In addition, you never want to push the
baseline if there are special conditions (e.g., unfamiliar aircraft, pilot
fatigue) present for this flight.
might find it helpful to talk through both your newly established personal
minimums and any 'push-the-envelope' plans with a well-qualified flight
Step 6 - Stick to the Plan!
you have done all the thinking required to establish baseline personal minimums,
'all' you need to do next is stick to the plan. As most pilots know, that task
is a lot harder than it sounds, especially when the flight is for a trip that
you really want to make, or when you are staring into
the faces of your disappointed passengers. Here's
where personal minimums can be an especially valuable tool. Professional pilots
live by the numbers, and so should you. Pre-established hard numbers can make it
a lot easier to make a smart 'no go' or 'divert' decision than a vague sense
that you can 'probably' deal with the conditions that you are facing at any
given time. In addition, a written set of personal minimums can also make it
easier to explain tough decisions to passengers who, after all, trust their
lives to your aeronautical skill and judgment.
Susan Parson is a Special Assistant in Flight
Standards' General Aviation and Commercial Division and an active general
aviation pilot and flight instructor. She welcomes your thoughts and ideas on
best practices for establishing and adjusting your personal minimums. Send