Download Determining Personal Minimums and more Schemes and Mind Maps Aerodynamics in PDF only on Docsity!
Determining Personal Minimums
Single Pilot IFR
What are my personal minimums today? For those of us who are not professional pilots, this is a question we ask ourselves before every IFR flight. Instrument flying is a numbers game and our personal minimums on the day we fly are just as important as any of the other numbers we carefully determine to ensure a safe flight. Early in the flight planning process we need to methodically establish our personal minimums for that flight.
IFR competency is a moving target. It is affected by a number of factors like equipment capabilities, pilot familiarity with the particular aircraft, pilot experience, and the pilot’s physical and mental condition. Competency also declines with lack of practice. Personal minimums checklists, such as the FAA’s Personal Minimums Checklist (FAA-P-8740-56) are a good start, but they don’t provide a structured means for arriving at a specific number. We know it is somewhere between VFR and 200 and ½ ceiling and visibility. But, rather than making an off- the-cuff guess, we need a simple, logical way to arrive at a specific, realistic number.
This paper provides a structured, analytic method for determining your personal minimums in the form of a simple worksheet. Some judgment is still required. However, the areas of judgment ones pilots can readily deal with. The factors we need to quantify relate to equipment condition and skill level:
Equipment - Is the aircraft one you fly regularly?
- Are you intimately familiar with the aircraft’s Nav/Com equipment?
- Are back-up systems available and working?
Skill Level - How long has it been since you last flew?
- How good are you at flying instrument approaches?
I. Starting Considerations
Before we get to the numbers, there are some starting considerations that need to be addressed. Flying is demanding and the pilot must be physically and mentally fit. To help ensure that this is so, there are several physiological factors to consider. These are Go/No-Go factors, as opposed to minimums-limiting factors. A conscientious pilot will have little trouble assessing their applicability. The FAA’s checklist serves well here and includes:
Sleep Are you sufficiently rested? If you are dog-tired and worn out, it will be hard to do a competent and safe job in the air.
Food and Water Instrument flying is demanding and the body needs proper nourishment.
Alcohol The FAA says there must be a minimum of 8 hours between consuming alcohol and flying. Many pilots consider 12 or even 24 hours a better minimum.
Drugs and Medication If you are on medication, either over the counter or prescription, is it safe to be flying? If you don’t know, don’t go. The effect of medications at altitude can be devastating.
Stressful Events If you are under stress to the point that it may affect your judgment and ability to concentrate in the air, cancel the trip.
Illnesses How do you feel? If you are suffering from an ailment such as the flu or a severe cold, you are better off on the ground. Delay the trip until you are well.
II. Competency Scale
Four levels of competency (ceiling and visibility) are used. They provide a reasonable graduation in level of challenge between VFR and precision approach minimums without making the process overly complex.
Level 1 1000 ft 3 mi Level 2 800 2 Level 3 500 1 Level 4 200 ½
III. Competency Adjustment Factors
There are four decisions we need to make to complete the Personal Minimums worksheet and determine our personal minimums for today’s flight. (Refer to the attached worksheet for the rating scales discussed below.)
Note that the values for competency adjustment in the worksheet are provided as a starting point. They should be tailored to each individual as explained in Section V.
1. Starting Competency In determining our personal minimums, we start with the best possible situation (equipment and demonstrated capability) and subtract from that according to the conditions that reduce our skill level.
What are the best minimums we can start with? On practice sessions you will have demonstrated that you are capable of flying a precision approach down to the lowest minimums which are typically 200 and ½ or Level 4. However, depending on your experience, this may be more than you are ready to take on in real instrument conditions. So rather than the best you have demonstrated, you should use the highest level of competency you feel comfortable dealing with in real IMC conditions. For newly rated instrument pilots this may be Level 1. For highly experienced instrument pilots it may be Level 3 or 4.
2. Equipment Condition What is the equipment situation you will be working with? Are you intimately familiar with the particular aircraft we will be flying? This means knowing from memory things like the power settings for different flight configurations, operating airspeeds, and how the systems work. Are you familiar with the avionics to the point that you can use them effectively without reference to a manual? We are tempted to conclude that changing between airplanes of the same make and model is not significant to the pilot. Use caution in making this assumption. Airplanes are seldom exactly alike.
In this model we assume a GPS installation with a good moving map display, such as a Garmin GNS 430, for situational awareness. A good, IFR-approved GPS significantly
- The aircraft you will be flying is one you are very familiar with including its Nav/Com equipment. It also has a good GPS and 3-axis autopilot. In this case there is no adjustment for Equipment Condition.
- It has been less than 2 weeks since you last flew this aircraft. Thus there is no adjustment for Skill Deterioration Since Last Flight.
- Your last approach was a practice session 5 weeks ago. Thus your Skill Deterioration Since Last Approach is -1 Level.
From this information, you complete the worksheet as follows:
Personal Minimums Worksheet Date: ______
1. Starting Competency 1000 3 Level 1 800 2 Level 2 500 1 Level 3 200 ½ Level 4
Level ____
2. Equipment Conditions Familiar Aircraft Adjust by 0 Unfamiliar Aircraft - No GPS - No 3-Axis Autopilot -
____
3. Weeks Since Last Flight ____ Last flight 0-2 wks Adjust by 0 3-4 - ______ 5-6 - >6 -
____
4. Weeks Since Last Approach ____ Last approach 0-4 wks Adjust by 0 5-7 - ______ 8-10 - >10 -
____
Current Personal Minimums (Sum 1+2+3+4) Level ____
Post-Flight Assessment
The worksheet calculation shows your Personal Minimums are currently at Level 2 (800 and 2). Unless the forecast conditions at our destination are 800 and 2 or better, you don’t go.
V. Customizing the Model
Each of us is unique in terms of how our skills are affected by time and equipment. For this tool to be most useful, it needs to be tailored for the individual. This means developing a personal set of scale factors for the worksheet tables, which we can do over time, by self-evaluation.
Self-evaluation required is an objective review at the end of each instrument flight as to how the flight went from the point of view of instrument flying competency. You then take the worksheet you completed before the flight and compare what was predicted with how you actually did. If necessary, you adjust the appropriate tables to reflect this experience.
In the example in Section V, you concluded that your personal minimums were 800 and 2 (Level
- In our post flight self-assessment, we ask ourselves if 800 and 2 felt like the right level. How did we make out flying the approach? How well did we hold assigned altitudes? How difficult was it to stay on the localizer? Based on our assessment, we can quickly conclude if the personal minimums determined from the worksheet were correct for this instance. Save your worksheets. You will want to revisit your conclusions later after several such sessions to finally lock in the table values that are right for you.
Doing such self-assessments on a regular basis will quickly refine the tables for your personal situation. Don’t worry that you have not calibrated each table across its full range. Our individual flying patterns tend to be fairly consistent over time so the conditions most important will get the most attention and be sufficiently accurate.
Flying competency is affected by our total time as pilot in command. You will see a change from year-to-year as you accumulate experience. We can expect a 1,000-hour pilot to be more competent than a 200-hour pilot. Similarly, a 10,000-hour veteran will have honed his flying skills to a sharp edge and deeply ingrained them in his sub conscience. At some point, a worksheet such as this is unnecessary since your competency will be intuitively obvious.
Finally, don’t forget the risk factors associated with the GPS and autopilot systems. If one of these fails during the flight, a reassessment of your personal minimums may suggest a deviation to your alternate.
October 4, 2002
Peter Cassidy [email protected]
