ASCI Attitude Instrument Flying

Lesson Overview & Allocations

• Attitude Instrument Flying Course Components and Time Allocations:

  • Introduction and Homework Review: $15\,\text{minutes}$

  • Attitude Instrument Flying Concepts: $5\,\text{minutes}$

  • Fundamental Skills: $10\,\text{minutes}$

  • Basic Flight Maneuvers: $15\,\text{minutes}$

  • Partial Panel Flying: $5\,\text{minutes}$

  • Unusual Attitudes and Recoveries: $5\,\text{minutes}$

  • Conclusion and Review: $5\,\text{minutes}$

Fundamentals of Attitude Instrument Flying

• Definition:

  • Attitude Instrument Flying is defined as controlling an aircraft's attitude, altitude, heading, and performance solely by reference to flight instruments rather than outside visual references.

• Purpose and Safety:

  • Mastery of attitude instrument flying is vital for maintaining positive aircraft control and ensuring flight safety when visual reference to the natural horizon is lost in Instrument Meteorological Conditions (IMC).

• Aircraft Axes, Control Surfaces, Movement, and Stability:

  • Pitch Axis:

  • Primary Control Surface: Elevator (or Stabilator)

  • Airplane Movement: Pitch

  • Axis of Rotation: Lateral Axis

  • Type of Stability: Longitudinal Stability

  • Roll / Bank Axis:

  • Primary Control Surface: Ailerons

  • Airplane Movement: Roll / Bank

  • Axis of Rotation: Longitudinal Axis

  • Type of Stability: Lateral Stability

  • Yaw Axis:

  • Primary Control Surface: Rudder

  • Airplane Movement: Yaw

  • Axis of Rotation: Vertical Axis

  • Type of Stability: Directional Stability

  • Flight Control Function:

  • Flight control surfaces direct aircraft attitude by rotating the airplane around its three primary axes.

Human Physiology and Sensory Systems in Instrument Flight

• Sensory Reliability Warning:

  • Physical senses (bodily feelings and brain interpretations of gravity or movement) cannot be trusted to control an aircraft during blind or instrument conditions.

• Three Primary Orientation Systems:

  • Visual System:

  • Anatomy and Function: Uses photoreceptors in the retina comprising Rods (responsible for peripheral vision, low-light/night vision, and motion sensing) and Cones (responsible for central vision, color perception, and high-acuity detail).

  • Role: Provides the primary visual spatial orientation when outside references or flight instruments are observed.

• Vestibular System:

  • Anatomy and Function: Located in the inner ear. Contains Semicircular Canals (three fluid-filled tubular ducts oriented at right angles sensing angular acceleration in pitch, roll, and yaw) and Otolith Organs (Utricle and Saccule sensing linear acceleration and gravity).

  • Internal Structures: Semicircular canals feature ampullae containing a gelatinous structure called the cupula, hair cells, endolymph fluid, and filaments connected to the vestibular nerve.

• Postural / Kinesthetic System:

  • Anatomy and Function: Consists of sensory nerves throughout the peripheral nervous system and central nervous system (brain and spinal cord), sending sensations from pressure sensors in muscles, joints, tendons, and skin ("seat-of-the-pants" sensation).

Spatial Disorientation and Vestibular Illusions

• Spatial Disorientation Causes:

  • Results from conflicting signals between central vision and peripheral vision, or between visual cues and vestibular/kinesthetic inputs.

  • Highly prevalent in IFR (Instrument Flight Rules) conditions when peripheral visual horizon references are absent.

  • Motion Conflict Analogy: Standing or sitting in a stationary vehicle while an adjacent car moves, creating a false sensation of self-motion.

• Vestibular Disorientation:

  • Occurs when prolonged turns or accelerations cause inner ear fluid motion to stabilize, giving false neural signals that lead the brain to perceive motion or attitude changes that are not actually occurring.

• Prevention and Mitigation Strategies:

  • Restricted Visibility Risk: Spatial disorientation almost exclusively occurs when visibility is reduced or eliminated.

  • Continuous Awareness: Pilots must anticipate spatial disorientation whenever outside visual references are degraded.

  • Professional Training: Thorough ground and flight training focusing on flying solely by reference to instruments is mandatory.

  • Instrument Currency: Maintaining continuous proficiency and instrument currency.

  • Fundamental Rule in IMC: Never trust bodily sensations while flying in Instrument Meteorological Conditions; rely entirely on calibrated flight instruments.

Flight Instrument Displays and Layouts

• Traditional Analog Panel ("Six-Pack") Layout:

  • Top Row: Airspeed Indicator (ASI), Attitude Indicator (AI), Altimeter (ALT).

  • Bottom Row: Turn Coordinator (TC), Heading Indicator (HI / Directional Gyro), Vertical Speed Indicator (VSI).

  • Engine and Power Displays: Manifold Pressure (MP) Gauge and Tachometer (RPM).

• Electronic Glass Cockpit Primary Flight Display (PFD - e.g., Garmin G1000):

  • Central Pitch/Roll Display: Large attitude indicator (sky/ground artificial horizon) with pitch ladder and roll scale pointer.

  • Airspeed Tape: Moving vertical tape on the left side of the display.

  • Altitude Tape: Moving vertical tape on the right side of the display.

  • Vertical Speed Indicator (VSI): Vertical tape adjacent to the altitude scale.

  • Horizontal Situation Indicator (HSI): Circular compass rose centered below the horizon display.

  • Slip/Skid Indicator: Trapezoid indicator located beneath the top roll pointer.

  • Turn Rate Indicator: Tick marks and turn rate trend vector positioned on the HSI.

Fundamental Skills of Instrument Flying

• Positive Aircraft Control:

  • Achieving positive aircraft control relies on two fundamental skills: Scan (Cross-Check) and Instrument Interpretation.

• Fundamental Skill 1: Scan / Cross-Check:

  • Definition: The process of maintaining a logical, continuous, and systematic visual inspection of flight and navigation instruments.

  • Standard Cross-Check Techniques:

  • Selected Radial Cross-Check:

    • Execution: The pilot's gaze spends the majority of time on the Attitude Indicator, radially scanning out to an individual performance instrument (ASI, ALT, HI, VSI, TC) and returning directly to the Attitude Indicator after checking each instrument.

    • PFD Scan Order Example: Start at Pitch Attitude (Center) $\rightarrow$ Airspeed Indicator (Left) $\rightarrow$ Center $\rightarrow$ Altimeter/VSI (Right) $\rightarrow$ Center $\rightarrow$ Slip/Skid Indicator (Up) $\rightarrow$ Center $\rightarrow$ Heading Indicator (Down) $\rightarrow$ Center.

- Rectangular Cross-Check: Moving eyes in a smooth, continuous rectangular perimeter across all six basic flight instruments.
- Inverted-V Cross-Check: Scanning from the Attitude Indicator down to the Turn Coordinator, up to the AI, down to the VSI, and back to the AI.

• Three Common Scanning Errors:

  • Fixation: Staring continuously at a single flight instrument while neglecting all other instruments in the panel.

  • Omission: Leaving out one or more critical instruments from the scan sequence entirely.

  • Emphasis: Placing disproportionate importance on a single instrument over others during specific maneuvers.

• Fundamental Skill 2: Instrument Interpretation:

  • Understanding operational mechanics, gyroscopic/pitot-static principles, and failure symptoms of each instrument.

  • Verifying validity: Cross-checking instruments to confirm accuracy (e.g., determining whether a pitch-up indication on the AI corresponds to an actual climb on the VSI and Altimeter, or recognizing a turn without bank).

Basic Attitude Instrument Flying (BAI) Concepts and Methods

• Method 1: Control and Performance Concept:

  • Structure: Categorizes instruments into Control Instruments, Performance Instruments, and Navigation Instruments. Relies heavily on the Attitude Indicator for establishing flight maneuvers.

  • Control Instruments:

  • Attitude Indicator (AI)

  • Turn Coordinator + Inclinometer Ball / Slip-Skid Indicator

  • Engine Power Gauges: Manifold Pressure (MP) and Tachometer (RPM)

  • Performance Instruments:

  • Airspeed Indicator (ASI)

  • Altimeter (ALT)

  • Vertical Speed Indicator (VSI)

  • Navigation Instruments:

  • GPS, VOR, Localizer, HSI, and Course Deviation Indicators

  • Four Steps of Control and Performance Method:

  • Step 1: Establish pitch attitude and power setting on control instruments.

  • Step 2: Trim the aircraft to maintain the desired attitude with neutral control pressures.

  • Step 3: Cross-check performance instruments (ALT, ASI, VSI) to verify if target performance is achieved.

  • Step 4: Adjust attitude and/or power settings on control instruments as required.

• Method 2: Primary and Supporting Concept:

  • Structure: Categorizes instruments as Primary or Supporting based on the maneuver being flown, divided across four control elements: Pitch, Bank, Power, and Trim.

  • Primary Instruments: The instrument that provides the most direct, pertinent, and essential information for a specific parameter during a given flight condition.

  • Supporting Instruments: Instruments that assist in maintaining or monitoring target parameters displayed on primary instruments.

  • Four Components of Aircraft Control:

  • Pitch Control: Adjusting elevator pitch attitude around the lateral axis.

  • Bank Control: Adjusting aileron bank angle around the longitudinal axis.

  • Power Control: Adjusting throttle/thrust to control airspeed or rate of climb/descent.

  • Trim Control: Adjusting trim devices (elevator, aileron, rudder) to relieve control column pressures.

Instrument Categorization Matrices

• Complete Primary and Supporting Instrument Function Table:

• Detailed Maneuver Reference Breakdown:

  • Straight and Level Flight:

  • Pitch: Primary = Altimeter (ALT); Supporting = Attitude Indicator (AI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Heading Indicator (HI); Supporting = Attitude Indicator (AI), Turn Coordinator (TC)

  • Power: Primary = Airspeed Indicator (ASI); Supporting = Manifold Pressure (MP) and/or Tachometer (RPM)

  • Airspeed Changes in Straight and Level Flight:

  • Pitch: Primary = Altimeter (ALT); Supporting = Attitude Indicator (AI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Heading Indicator (HI); Supporting = Attitude Indicator (AI), Turn Coordinator (TC)

  • Power: Primary = MP and/or RPM initially; Supporting = Airspeed Indicator (ASI) as target airspeed is approached

  • Establishing a Level Standard-Rate Turn:

  • Pitch: Primary = Altimeter (ALT); Supporting = Attitude Indicator (AI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Attitude Indicator (AI); Supporting = Turn Coordinator (TC)

  • Power: Primary = Airspeed Indicator (ASI); Supporting = MP and/or RPM

  • Stabilized Standard-Rate Turn:

  • Pitch: Primary = Altimeter (ALT); Supporting = Attitude Indicator (AI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Turn Coordinator (TC); Supporting = Attitude Indicator (AI)

  • Power: Primary = Airspeed Indicator (ASI); Supporting = MP and/or RPM

  • Change of Airspeed in Level Turn:

  • Pitch: Primary = Altimeter (ALT); Supporting = Attitude Indicator (AI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Turn Coordinator (TC); Supporting = Attitude Indicator (AI)

  • Power: Primary = Airspeed Indicator (ASI); Supporting = Airspeed Indicator (ASI)

  • Transitioning from Straight and Level to Constant Airspeed Climb:

  • Pitch: Primary = Attitude Indicator (AI); Supporting = Airspeed Indicator (ASI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Heading Indicator (HI); Supporting = Attitude Indicator (AI), Turn Coordinator (TC)

  • Power: Primary = MP and/or RPM; Supporting = Airspeed Indicator (ASI)

  • Straight Constant Airspeed Climb:

  • Pitch: Primary = Airspeed Indicator (ASI); Supporting = Attitude Indicator (AI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Heading Indicator (HI); Supporting = Attitude Indicator (AI), Turn Coordinator (TC)

  • Power: Primary = MP and/or RPM; Supporting = Airspeed Indicator (ASI)

  • Power Increase into Straight Constant-Rate Climb:

  • Pitch: Primary = Attitude Indicator (AI); Supporting = Airspeed Indicator (ASI), Vertical Speed Indicator (VSI)

  • Bank: Primary = Heading Indicator (HI); Supporting = Attitude Indicator (AI), Turn Coordinator (TC)

  • Power: Primary = MP and/or RPM; Supporting = None

  • Straight Constant-Rate Stabilized Climb:

  • Pitch: Primary = Vertical Speed Indicator (VSI); Supporting = Attitude Indicator (AI)

  • Bank: Primary = Heading Indicator (HI); Supporting = Attitude Indicator (AI), Turn Coordinator (TC)

  • Power: Primary = Airspeed Indicator (ASI); Supporting = MP and/or RPM

• Inoperative Instrument Rule:

  • For straight-and-level flight, if the Heading Indicator (HI) is inoperative, the Magnetic Compass replaces the HI as the primary bank instrument.

• Quality of Turn Indicator:

  • The inclinometer ball of the turn coordinator or turn-and-slip indicator displays turn quality (coordination vs. slip or skid).

Basic Flight Maneuvers & Transitions

• Three Steps for Stabilized Maneuvers:

  • Step 1: Current Stabilized Condition (e.g., straight-and-level cruise).

  • Step 2: Transition from current condition to new stabilized condition (adjusting pitch, bank, and power settings).

  • Step 3: New (Now Current) Stabilized Condition (holding new altitude, heading, airspeed, or vertical speed).

• Primary Instrument Identification Rule:

  • The instrument that alerts the pilot to initiate a control pressure change is defined as the primary instrument for that parameter.

  • Example: Noticing a $30\,\text{foot}$ deviation on the Altimeter identifies the Altimeter as the primary pitch instrument for straight-and-level flight.

• Types of Climbs and Descents:

  • Constant Airspeed Climb (e.g., establishing $V_y$ climb attitude and full power).

  • Constant Rate Climb (using VSI as primary pitch instrument).

  • Constant Airspeed Descent.

  • Constant Rate Descent.

• Missed Approach Transition Example:

  • Rapid transition from level approach flight at low airspeed to full power climb at $V_y$.

• Air Traffic Control Clearance Execution:

  • ATC Clearance: "Riddle 270 climb and maintain 6000 feet".

  • Steps: Pitch up to climb attitude on Attitude Indicator, increase power to climb power, trim elevator, cross-check Airspeed Indicator and Heading Indicator, verify climb rate on VSI, and prepare level-off $50\,\text{feet}$ to $100\,\text{feet}$ below $6000\,\text{feet}$.

Partial Panel Flying

• Definition:

  • Partial panel flying occurs when one or more primary flight instruments fail during flight (such as a vacuum pump failure disabling the Attitude Indicator and Heading Indicator, or an AHRS system failure in glass cockpits).

• Vacuum System Failure (Analog Panels):

  • Loss of gyroscopic pitch, roll, and heading indicators.

  • The pilot must execute full instrument control using remaining pitot-static instruments (ASI, ALT, VSI), Turn Coordinator, and Magnetic Compass.

• AHRS Unit Failure (Garmin G1000 PFD):

  • An Attitude and Heading Reference System (AHRS) failure presents a large red 'X' over the artificial horizon display accompanied by the yellow/red text warning "ATTITUDE FAIL".

  • Heading indicator digital rose displays an "HDG" flag failure.

  • Pilot must immediately transition scan to standby analog instruments or perform partial panel scanning techniques.

Unusual Attitudes and Recovery Procedures

• Definition:

  • An unusual attitude is any pitch or bank orientation not normally required for standard instrument maneuvers.

• Immediate Recovery Action:

  • As soon as an unusual attitude is recognized, recovery must be initiated immediately.

• Diagnostics and Verification:

  • Do not rely solely on the Attitude Indicator, as vacuum gyros can tumble or AHRS units can fail/flag errors during severe pitch and roll excursions.

  • Always check the Airspeed Indicator first to determine whether the aircraft is in a nose-high or nose-low attitude.

• Recovery Procedures:

  • Nose-High Unusual Attitude:

  • Indications: Airspeed rapidly decreasing, altitude increasing, VSI showing high rate of climb.

  • Step 1: Increase power to maximum to prevent an impending stall.

  • Step 2: Apply forward elevator pressure to lower pitch attitude and unload the wing load factor.

  • Step 3: Roll wings level using coordinated aileron and rudder pressure.

  • Step 4: Re-establish straight-and-level flight.

• Nose-Low Unusual Attitude:

  • Indications: Airspeed rapidly increasing, altitude decreasing, VSI showing high rate of descent.

  • Step 1: Reduce power to idle to prevent exceeding structural airspeed limits ($V_{ne}$).

  • Step 2: Roll wings level first using coordinated aileron and rudder. (Rolling wings level prior to pulling back prevents accelerated stalls and wing G-load overstress).

  • Step 3: Apply smooth back elevator pressure to raise pitch attitude to level flight.

  • Step 4: Re-establish straight-and-level flight and restore cruise power.

• Standard Upset Recovery Template:

  • Step 1: Disconnect the wing leveler or autopilot.

  • Step 2: Apply forward column or stick pressure to unload the airplane.

  • Step 3: Aggressively roll the wings to the nearest horizon.

  • Step 4: Adjust power as necessary by monitoring airspeed.

  • Step 5: Return to level flight.

• Advanced Glass Cockpit Unusual Attitude Displays:

  • Bank Angle Warning: Screen display declutters and provides visual guidance when rolled past $60^\circ$.

  • Pitch Chevrons: Large red chevrons ("V" marks) appear on the Garmin G1000 PFD pointing toward the horizon to guide pitch recovery.

• Common Errors Leading to Unusual Attitudes:

  • Improper trimming techniques.

  • Poor Crew Resource Management (CRM) skills.

  • Fixation on single instruments or cockpit distractions.

  • Attempting to recover by sensory bodily sensations rather than flight instruments.

  • Failure to practice basic attitude instrument flying routinely.

Control / Performance Data Collection

• Purpose and Operational Utility:

  • Profiling and charting aircraft performance parameters (pitch attitude, power settings, flap configurations, resulting airspeeds, and vertical speeds) standardizes flight control, simplifies instrument approach procedures, and prevents pilot over-controlling.

• Control / Performance Chart Data Elements:

  • Flight Phases Evaluated:

  • Climb: Flaps 0, Flaps 10

  • Straight & Level: Flaps 0, Flaps 10, Flap Mid, Flaps All

  • Descent (Flaps 0 Deg): $500\,\text{fpm}$, $800\text{--}1000\,\text{fpm}$

  • Descent (Flaps 10 Deg): $500\,\text{fpm}$, $800\text{--}1000\,\text{fpm}$

  • Approach Profiles: 1. Approach Initial, 2. Approach Intermediate, 3. Approach Final - Precision, 4. Approach Final - Non-Precision, 5. Approach - Level @ MDA, 6. Holding.

  • Recorded Parameters: Pitch Attitude (degrees), Power Setting, Configuration (flaps), Performance (Airspeed in Knots and Attitude).

Review & Self-Assessment Questions

• Core Review Concepts:

  • Name the 2 basic concepts of attitude instrument flying: Control & Performance Method; Primary & Supporting Method.

  • Explain how to determine an unusual attitude and how to recover: Check Airspeed Indicator first; Nose-High requires Max Power + Forward Elevator + Roll Level; Nose-Low requires Idle Power + Roll Level + Smooth Back Elevator.

  • Explain how to accomplish a constant airspeed descent: Reduce power, pitch to target airspeed attitude on AI, trim, and monitor ASI as primary pitch instrument.

  • What are the 2 fundamental instrument flying skills?: Cross-check (Scan) and Instrument Interpretation.

  • What are the 3 scanning errors?: Fixation, Omission, and Emphasis.

  • What are the primary instruments for pitch, power, and bank while established in a constant airspeed climb?: Pitch = Airspeed Indicator; Bank = Heading Indicator; Power = Tachometer / Manifold Pressure.

  • Describe how to determine that an instrument has failed: Cross-check performance instruments against control instruments to identify contradictory readings, frozen pointers, or red 'X' failure flags (such as AHRS ATTITUDE FAIL).