Flight by Reference to Instruments

Fundamentals

Attitude instrument flying means control of the aircraft's spatial position by using instrument's rather than outside visual references

Two basic methods:
1. Control and performance (attitude + power = performance)
2. Primary and Supporting

Pitch Instruments
attitude indicator (AI)
altimeter (ALT)
airspeed indicator (ASI)
vertical speed indicator (VSI)

Bank Instruments
Attitude indicator (AI)
Heading indicator (HI)
Magnetic compass (MC)
Turn coordinator (TC)

Power Instruments
Airspeed indicator (ASI)
Engine instruments

• manifold pressure gauge (MP)
• tachometer (RPM)

For any maneuver or flight condition

Primary instruments
One in each group (pitch, bank, power)
Provide most pertinent and essential information
Indication stable with correct flight (shows greatest change with improper aircraft control)

Secondary instruments
Back up and supplement primary instruments
Advantages
Emphasized by FAA (Instrument Flying Handbook)
Requires specific knowledge and interpretation of each individual instrument during training
Helps avoid over-dependence on attitude indicator, facilitating partial panel flight

Fundamental skills

1. Cross-Check
Proficient pilot adjusts scan rate and sequence to specific flight situation
Continuous, logical observation of instruments for attitude and performance information

Common Errors

Fixation
Omission
Emphasis

2. Interpretation
Applied knowledge of

instrument construction and operating principles
aircraft performance capabilities (POH)
Learn what performance to expect and combination of instruments to interpret for each flight condition

3. Control
Four components
Pitch
Bank
Power
Trim
Common error - Tension - use relaxed touch

A. Straight-and-Level Flight
To determine that the applicant
Exhibits instructional knowledge of teaching straight-and-level flight by describing
a. The relationship of pitch, bank and power in straight-and-level flight
Pitch varies with airspeed and load
At constant airspeed, there is only one specific pitch attitude for level flight
Uncorrected bank leads to decreasing pitch with increasing airspeed
b. Procedure using full panel and partial panel
Full panel


Maintain constant altitude (+/- 100 ft) and heading (+/- 10°) at a given contstant airpseed (+/- 10 kt)
Constant altitude
Adjust pitch to maintain assigned ALT with VSI = 0
Trim to relieve control pressures
Correct small deviations (< 100 feet) with pitch only
½ bar width on AI
VSI < 200 fpm
Larger deviations may require use of pitch and power
Initial 1 bar width on AI
VSI = 2 x error in alt
VSI is primary pitch instrument during altitude corrections
Constant heading
Adjust aileron and rudder pressures to keep HI constant, wings level on AI and TC with ball centered
Corrections of heading deviations
Coordinated aileron and rudder
Bank angle < number of degrees off and < standard rate (3°/sec)
Constant airspeed - adjust power (MP, RPM) to maintain airspeed
Prompt, smooth, small corrections
SLF
Pitch Bank Power
Primary ALT HI ASI
Secondary AI, VSI AI, TC MP, RPM
Partial panel (AI and HI inoperative)
Maintain altitude with ALT, VSI, ASI
Hold heading with TC level, centered ball, and MC
SLF-Partial Panel
Pitch Bank Power
Primary ALT TC ASI
Secondary VSI MC MP, RPM
c. Coordination of controls and trim
Keep ball centered
Trim to relieve control pressures
Exhibits instructional knowledge of common errors related to straight-and-level flight by describing
a. Slow or improper cross-check during straight-and-level flight
ALT needle tip 0, AI scale pointer (bank index) 0, ASI needle tip on speed,
TC level & centered ball, HI needle tip center of bug, VSI needle tip 0
b. Improper power control
Learn/use MP that you know will result in approximate desired airspeed in SLF
If airspeed changes, cross-check VSI, ALT before any power change
c. Failure to make smooth, precise corrections as required
Aim for precision: heading +/- 2°, airspeed +/- 2 knots, altitude +/- 20 feet
Beware overcontrolling
Use two step corrections
Just enough control pressure to stop needle movement
A bit more to start smooth correction
d. Uncoordinated use of controls
Keep the ball centered
e. Improper trim control
Trim to relieve control pressures
Small, frequent adjustments
Demonstrates and simultaneously explains straight-and-level flight from an instructional standpoint
Analyzes and corrects simulated common errors related to straight-and-level flight

http://greggordon.org/flying/CFIIPTSVIAStraightAndLevel.htm