Summary
Scan techniques are very important to pilots flying by Instrument Flight Rules (IFR) and these pilots spend a considerable amount of time developing sophisticated techniques. As a student pilot you need to develop sufficient instrument skills to maintain control of the airplane should you inadvertently find yourself in IFR conditions, to avoid becoming disorientated during night flight and to satisfy the Private Pilot Practical Test Standards. Your overall aircraft control will also benefit from an enhanced understanding of the instruments.
Three scan techniques to get you started:
Straight and Level
Straight and level practical test standards
The first technique you need is to maintain straight and level flight. To do this use a V scan. This will entail moving your eyes as shown above. If the directional indicator moves level your wings by reference to the attitude indicator. If the altitude changes adjust your pitch whilst referencing the attitude indicator. If the airspeed changes, whilst the altitude remains stable you will need to adjust the power setting. The secrets of success whilst flying by reference to instruments are to keep your eyes moving and to make very small control inputs.
Standard Rate Turn
Turns to headings practical test standards
Having established straight and level flight the next skill you need is to make a standard rate (3 degrees per second turn) at constant airspeed. For a standard rate turn use an inverted L scan. Initially establish a bank of about 15 degrees using the attitude indicator. Once the turn has been established move your eyes as shown above. If the altitude changes make a pitch adjustment whilst referencing the attitude indicator, if the airpeed changes whilst the altitude is stable make a power adjustment, if the wingtip of the airplane in the turn coordinator is not aligned with the reference line make a bank adjustment whilst referencing the attitude indicator. Since a standard rate turn is three degrees per second maintaining this configuration for one minute should result in course reversal. This is a useful technique if one has inadvertently entered IFR conditions. Having reversed course you would maintain straight and level flight and hopefully return to an area of VFR conditions. However good flight planning to avoid unsuitable weather is infinitely preferable.
Climb or Descent
Constant airspeed climbs practical text standards
The third basic instrument skill you need is the ability to climb or descend. To maintain a stabilized climb or descent use a lazy L scan. Having established the desired rate of climb or descent by setting the desired power setting and pitching for a specific airspeed you may maintain this condition by scanning as shown. Airspeed changes may be adjusted using power. Heading changes should lead to checking the attitude indicator to see if your wings are level. Vertical speed changes may be adjusted using pitch. On reaching your desired altitude use the attitude indicator to reestablish straight and level flight and then revert to the V scan.
