Monday, 15 May 2017

WHY INSTRUMENT FLYING IS AN ART, NOT A SCIENCE

Acknowledgements: AIR FACTS/ John Zimmerman

There’s a lot of talk about “primary and supporting” or “control and performance” methods of instrument flying. Similarly, some instrument students are so weighed down with mnemonics that they can hardly fly the airplane – was it “turn, twist, time”, or “twist, turn, tune”? These concepts may have some value, but relying too much on them during instrument training risks confusing instead of helping the student. Sure, if you can define all the variables and possible scenarios you can create a model that guarantees consistent performance; which may work for computers, but it’s not the way humans are wired! Earning an instrument rating is not like writing a computer program. You already know how to fly, but now you need to learn a new way to do it.

So instead of talking about primary and supporting instruments, a great CFI will teach the student what normal looks like on the instrument panel. Then, how do the instruments react to power changes, steep turns, or full flaps? Finally, it’s worth flying a few approaches, without a long discussion about precision vs. non-precision or LPV vs. LNAV. Just fly an approach and try to keep the needles crossed, all the while watching the panel.

A more formal syllabus will follow, but the real goal is IFR fluency. A proficient instrument pilot doesn’t have to read an instrument and translate it into VFR; one can sense immediately where the airplane is and where it’s going - a state of mind where you are hardly even thinking. Getting to that point demands practice and yes, even a little time with the textbook. But instead of rigid rules, I prefer to focus on a few good habits:
·         
     Keep the scan moving. Technically called “instrument cross-check”, it determines the structure of things, and while you can’t always describe it, you know it when you see it. Scanning the instruments does not mean a random or rushed path, but rather a disciplined approach to assembling all the important information and creating a complete picture of the flight.
·         
     The attitude indicator gets the most attentionWhile different pilots will have different scans, the attitude indicator should be at the centre of all of them. Instruments can fail or lie, but when in doubt, start with attitude. It usually tells the truth.
·       
     Have a theory before you make a control inputThis is really a mind-set: you don’t “follow the needles”, they follow your plan. Before beginning a take-off, an approach, or a hold, you should have a heading, power setting, and vertical speed in mind – this is your theory. Then, during the manoeuvre, you can look at the instruments with an expectation of what they should show. If reality doesn’t match your theory, make a refinement. This leads to much more precise and stable flying.
·    
   Use a few shortcutsSometimes you need an educated guess to make your flight a little  smoother. Three favourites relate to turns, level-offs, and intercepts:
·         For rolling out of turns, a good guess is to start reducing bank when you’re within half the degrees of your bank angle; e.g. Start applying left aileron in a 30-degree right turn when you’re within 15 degrees of your desired heading.
·         To prevent an aggressive pitch up or down, begin to level out when you’re within 20% of the climb rate: e.g. At 5800 feet if you’re climbing for 6000 feet at a rate of 1000 fpm.
·       When choosing an intercept angle, a good start is to put the lubber line on the CDI needle (this requires an HSI) – a larger deviation will require a larger intercept angle. 
·         
      Know the essential profiles for your airplaneThis can make instrument flying a lot easier.  Memorize the key power/flap/gear/air-speed configurations for each airplane you fly; including  max. climb, initial approach, and final approach. For example, if you know that 20 inches of  manifold pressure and 10 degrees of flap will deliver 100 knots in level flight, set that  configuration outside the final approach fix and get back to flying. Then, as you approach  glide-slope intercept, you can fine tune it if needed. It’s a great way to reduce workload at critical  times, and can also bail you out in an emergency.
·       
        Remember what matters. Even in a simple Cessna 172 cockpit, there are plenty of gauges,  switches, and knobs to distract you. Single pilot IFR is all about focusing on what is  important (attitude above all else) and occasionally checking to see how other things are going  (engine instruments green? CDI centred? Airspeed where you want it?). If you feel overwhelmed  by the radio or an emergency, focus on what is essential and what isn’t.

 So, while IFR flying may seem like a rigid, structured process to non-pilots, most instrument pilots  know better. At its finest, it is an art, not a science.

FLY SAFE!

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