Fundamental Instrument Maneuvers

What are the Basic Instrument Maneuvers?

Basic instrument maneuvers consist of straight-and-level flight, turns, climbs, descents, and combinations of these elements performed solely by reference to the flight instruments. These maneuvers are performed primarily through attitude instrument flying techniques.

Attitude Instrument Flying

Attitude instrument flying means establishing and maintaining the airplane’s attitude by reference to the flight instruments rather than outside visual references.

Primary Rule: Attitude + Power + Configuration = Performance

Attitude Instrument Flying Techniques

• Learn the combinations of attitude, power, and configuration that produce common flight conditions.
• Make small attitude changes and allow the airplane time to stabilize.
• Avoid chasing instrument indications with continuous control inputs.
• Maintain a continuous and systematic instrument cross-check.
• Use trim to relieve control pressures after establishing the desired attitude.

The Three Fundamental Skills of Attitude Instrument Flying

Instrument Cross-Check (Scan): A continuous and systematic observation of the flight instruments used to determine the airplane’s attitude and performance.

The purpose of the instrument scan is to:

• Help prevent spatial disorientation and unusual attitudes.
• Provide early recognition of a failed instrument.

Instrument Interpretation: The process of interpreting the indications observed during the instrument cross-check to determine the airplane’s attitude and performance.

Aircraft Control: The application of the appropriate control inputs necessary to achieve the desired aircraft performance.

The Four-Step Process Used to Change Attitude

1. Establish: Set the appropriate pitch attitude, bank angle, power setting, and aircraft configuration to achieve the desired performance.

• Pitch and bank changes are made by reference to the attitude indicator.
• Power changes are made by reference to the engine instruments.

2. Trim: Relieve control pressures after establishing the desired attitude and power setting.

3. Cross-Check: Verify aircraft performance by scanning the flight and engine instruments.

4. Adjust: Make small and smooth corrections for any deviations noted during the cross-check.

Adjusting for Deviations

Pitch: Use the attitude indicator to correct altitude deviations. A common rule of thumb is to establish a rate of climb or descent equal to approximately twice the altitude deviation, not to exceed 500 FPM.

Bank: Use the attitude indicator to correct heading deviations. A common rule of thumb is to use a bank angle approximately equal to the number of degrees off heading, not to exceed a standard-rate turn.

Power: Make power corrections by reference to the engine instruments and verify aircraft performance using the flight instruments. Required power changes are learned through experience in the aircraft.

Attitude Instrument Flying Methods

There are two basic methods for learning to control the aircraft by reference to instruments: control and performance, and primary and supporting. The methods differ in their reliance on the attitude indicator and interpretation of the other instruments.

Control and Performance Method

The control and performance method is an attitude instrument flying technique that establishes specific pitch attitudes, bank angles, power settings, and aircraft configurations (controls) to achieve the desired aircraft performance.

Consistent Setup = Predictable Results

Scanning Technique: The attitude indicator is the center of focus; therefore, the selected radial or T-scan is recommended.

Instrument Groups:

• Control: The attitude indicator and power instruments (tachometer and manifold pressure, if equipped).
• Performance: The altimeter, airspeed indicator, and vertical speed indicator. Other instruments are the heading indicator and the slip/skid indicator.
• Navigation: Ground-based or space-based navigation systems.

Basic Concept:

• All attitude changes should be made in reference to the control instruments (attitude and power).
• Once established, make note of the power settings and flight instrument indications.

Primary and Supporting Method

The primary and supporting method is an attitude instrument flying technique that emphasizes specific flight instruments as primary references for pitch, bank, power, and performance during a particular maneuver or flight condition. Less emphasis is placed on the attitude indicator.

Scanning Technique: The eyes should spend the most time on the primary instruments.

Instrument Groups:

• Primary: The instrument that displays the most pertinent information at any given time. There are three primary instruments for every maneuver: one for pitch, one for bank, and one for power.
• Supporting: The instruments that back up the primary instruments. There may be more than one supporting instrument for pitch, bank, and power.

Basic Concept:

• When transitioning between maneuvers, use the attitude indicator and power instruments (tachometer and manifold pressure, if equipped).
• Once established, begin scanning with proper emphasis on the primary and supporting instruments.

Instrument Scanning Techniques

Inverted V Scan

• Starting Position: Attitude indicator (home base)
• Eye Movements:
• From the attitude indicator to the turn coordinator and back
• From the attitude indicator to the vertical speed indicator and back
• Best Uses: Turns

T-Scan

• Starting Position: Attitude indicator (home base)
• Eye Movements:
• From the attitude indicator to the airspeed indicator and back
• From the attitude indicator to the heading indicator and back
• From the attitude indicator to the altimeter and back
• Best Uses: Straight-and-level flight

Selected Radial Scan (Hub and Spoke)

• Starting Position: Attitude indicator (home base)
• Eye Movements:
• From the attitude indicator (hub) to an instrument (spoke) and back
• The eyes are on the attitude indicator 80–90% percent of the time
• Best Uses: After major attitude changes, when flying in turbulence, and for precise maneuvering

Rectangular Scan

• Starting Position: Attitude indicator
• Eye Movements: From one instrument to the next in a box pattern (either direction)
• Best Uses: To rapidly scan all instruments for trends or instrument errors

Instrument Scanning Errors

Fixation: Staring at a single instrument, which often leads to an unnoticed change in other instruments.

Common reasons for fixation:

• Uncertainty or confusion with an instrument indication.
• Attempting to maintain or set an unnecessarily tight tolerance on a digital instrument.

Omission: Neglecting to include an instrument in the cross-check.

Common reasons for omission:

• An instrument installed in an awkward position, such as a standby instrument on the lower panel.
• Only scanning the primary flight display (PFD) due to its high reliability and ease of use.

Emphasis: Placing more attention on a single instrument instead of a combination of instruments.

Common reasons for emphasis:

• Elevating the importance of one instrument above another.
• Relying on the instrument that is most readily understood, even when it provides inadequate information.

Straight-and-Level Flight by Reference to Instruments

Procedure

1. Establish:

• Adjust the aircraft’s attitude and power setting to establish level flight at a constant airspeed.
• Altitude is to be maintained with zero bank and no yaw (constant heading).

2. Trim:

• Relieve all flight control pressures after a level attitude has been attained.
• The airplane should be able to maintain straight-and-level flight momentarily without any control inputs.

3. Cross-Check:

• Begin scanning with your preferred technique.
• Make a conscious effort to avoid scanning errors (fixation, omission, and emphasis).

4. Adjust:

• Make smooth and small corrections with positive control pressure.
• Avoid making large corrections that result in rapid attitude changes.
• Know and apply rules of thumb to correct for deviations in pitch and bank.

Common Errors for Straight-and-Level Flight

• Faulty trim procedure
• Insufficient cross-checking and interpretation of the instruments
• Fixation, omission, and emphasis errors during instrument cross-check
• Making excessive attitude corrections (“chasing the instruments”)

Constant Airspeed Climbs and Descents by Reference to Instruments

Procedure

Constant Airspeed Climbs:

• Raise the miniature aircraft to the nose-high indication for the predetermined climb speed. The attitude depends on the airplane’s performance.
• To maintain the current speed, set the climb power simultaneously with the pitch change.
• To climb at a slower speed, set climb power after the pitch change is established and the airspeed decreases to the climb speed.

• Once established, trim to relieve all flight control pressures.
• Scan the instruments with your preferred technique.
• Use smooth, small pitch adjustments to correct for airspeed deviations.

Constant Airspeed Descents:

1. To descend at a slower speed, reduce power and slow to the descent speed while maintaining straight-and-level flight.
2. Simultaneously lower the nose and reduce power to begin the descent.
3. Once established, trim to relieve all flight control pressures.
4. Scan the instruments with your preferred technique.
5. Use smooth, small pitch adjustments to correct for airspeed deviations.

Level-Off Procedure:

• Lead the level-off from the desired altitude by 10% of the vertical velocity.
• Simultaneously adjust power and pitch to return to level flight.
• To level off from a climb at a faster speed, pitch to return to level flight, then reduce power after reaching the cruise speed.
• Trim, cross-check, and make adjustments to establish straight-and-level flight.

Vertical S’s (Practice Flight Pattern)

Common Errors for Constant Airspeed Climbs and Descents

• Overcontrolling pitch on climb entry
• Failure to trim off new control pressures
• Failure to learn and use proper power settings
• “Chasing” the vertical speed indicator
• Failure to note the rate of climb or descent to determine the lead for level-offs
• “Ballooning” (allowing the nose to pitch up) on level-offs from descents

Turns to Headings by Reference to Instruments

Standard-Rate Turns

A standard-rate turn is a change in heading at a rate of 3° per second. The bank angle required to maintain a standard-rate turn varies with the true airspeed (TAS).

The bank angle for a standard-rate turn can be approximated with the following formula.

Bank Angle for Standard-Rate Turn = (KTAS ÷ 10) + 5

Procedure

1. Establish:

• Use the attitude indicator to establish the bank angle for a standard rate turn.
• Verify a standard rate turn on the turn coordinator (or turn-and-bank indicator).
• Apply aft control pressure on the pitch control to stop any altitude loss.

2. Trim:

• Relieve all flight control pressures after a level turn has been attained.

3. Cross-Check:

• Begin scanning with your preferred technique.
• Make a conscious effort to avoid scanning errors (fixation, omission, and emphasis).

4. Adjust:

• Make smooth and small corrections with positive control pressure.
• Use the same procedures as in level flight to control the airspeed and altitude once the maneuver is established.

Rollout Procedure:

1. To stop the turn on the desired heading, lead the rollout by about one-half the bank angle.
2. Strive for the same rate of rollout used to roll into the turn.
3. Apply forward control pressure on the pitch control to stop any ballooning (altitude gain).
4. If trim was used in the turn, retrim to relieve all flight control pressures.

S-Turns Across a Heading (Practice Flight Pattern)

Common Errors for Turns to Headings

Altitude Errors Resulting From:

• Preoccupation with bank control during turn entry and rollout
• Erratic rates of bank change on entry and rollout
• Failure to make pitch adjustments as the vertical lift component changes, resulting in a loss of altitude on entry and a gain of altitude on rollout
• Failure to trim during turn entry and following rollout (if the turn is prolonged)

Heading Errors Resulting From:

• Overcontrolling during turn entry and rollout
• Failure to use the proper degree of bank for the amount of heading change desired
• Failure to check the ball/brick when interpreting bank information
• Failure to remember the heading to which the aircraft is being turned due to preoccupation or rushing the maneuver

Timed Turns and Compass Turns [IFR]

Timed turns and compass turns are practiced using full-panel and partial-panel procedures to develop the learner’s ability to make accurate turns to headings without the use of the directional gyro.

Primary and Supporting Instruments

The attitude indicator, if available, is used to establish the approximate bank angle at the start of a turn. Once the turn is established, the turn coordinator becomes the primary instrument for bank control, the altimeter for pitch control, and the airspeed indicator for power control.

Procedure for Timed Turns

1. Determine the amount of time it will take to turn to the specified heading at a rate of 3° per second (standard rate turn).
2. Begin timing at the point where the airplane begins to roll into a bank.
3. Begin the rollout once the time has elapsed at the same rate used during the roll-in.

Procedure for Compass Turns

Considerations:

• The compass tends to lead on northerly headings and lag on southerly headings. The amount the compass leads or lags is affected by the degree of latitude.
• Account for the amount of time it takes to roll out of the turn. Consider using the 1/2 bank angle rule of thumb.
• No correction is needed when turning to an east or west heading.

Compass Turns to the North

Rule of Thumb: Stop the turn 15° plus half of the latitude before reaching the desired heading.

Compass Turns to the South

Rule of Thumb: Stop the turn 15° plus half of the latitude after passing the desired heading.

Oscar Flight Pattern

The Oscar pattern is an instrument flying exercise that combines standard-rate turns with constant airspeed climbs and descents.

The objective of the Oscar pattern is to:

• Develop instrument scanning techniques
• Build a foundation of skills that will be used in IFR procedures
• Prepare the learner to operate in a high-workload environment

Procedure

Pre-Maneuver Checks and Configuration:

• Clear the area
• Heading established and noted
• Altitude established
• Position near a suitable emergency landing area and away from hazards
• Set power and aircraft configuration:
• Perform the clean (cruise) configuration flow

• Do not exceed V_A or V_O

During the Maneuver:

• Airspeed remains constant (power is adjustable)
• All turns are 360° and made at standard rate
• All climbs and descents are made at 500 FPM
• Each period of straight-and-level flight should last 30 seconds (use a timer)

Variations for Added Complexity:

• Perform a flow check and checklist for each climb, descent, and level-off
• Perform the maneuver with a partial panel or using the standby instruments
• Brief an instrument approach

Risk Examples for Basic Instrument Maneuvers

When to Seek Assistance or Declare an Emergency

• Deteriorating weather conditions increase the likelihood of mid-air collisions and a loss of control; communicate with ATC and confess the nature of the situation.
• Icing conditions can lead to a loss of control; use anti-ice/deice systems, including pitot heat, and seek assistance from ATC.

Collision Hazards Related to an Inadvertent Entry into IMC

• Entering IMC or marginal weather conditions while on a VFR flight increases the likelihood of mid-air collisions; communicate with ATC and confess the nature of the situation.

Distractions, Task Prioritization, Loss of Situational Awareness, or Disorientation

• Distractions, task prioritization, loss of situational awareness, and disorientation increase the likelihood of errors, delayed or missed actions, and an inability to process information accurately and in a timely manner; minimize non-essential activities, follow the “Aviate, Navigate, Communicate” prioritization, and stay focused.

Fixation and Omission

• Fixating on a single instrument or omitting instruments from the scan can lead to a loss of situational awareness and aircraft control; seek training and maintain proficiency in instrument flying techniques: cross-checking, interpretation, and control.

Instrument Interpretation

• Misreading or misinterpreting flight instruments increases the likelihood of errors, spatial disorientation, and loss of control; understand the operation of each instrument and maintain proficiency in flying by reference to them.

Control Application Solely by Reference to Instruments

• Overcorrection and abrupt control movements can induce undesired aircraft attitudes and lead to a loss of control; practice smooth, coordinated inputs and maintain proficiency in the attitude instrument flying process: establish, trim, cross-check, and adjust.

Trimming the Aircraft

• Improper trim adjustments when flying by reference to the flight instruments can increase workload and the likelihood of making errors; trim the aircraft in all phases of flight using a three-step process: pitch, power, trim.

Situations that Could Lead to a Loss of Control or Unusual Attitude

• Distractions, spatial disorientation, and task saturation can lead to a loss of control and difficulty recovering to level flight; seek training in upset prevention and recovery techniques and in task management skills.

• Inadequate instrument scans can result in entry into unusual attitudes; seek training and maintain proficiency in instrument flying techniques: cross-checking, interpretation, and control.

Risk Examples for Instrument Flight Training

Situations That Can Affect Physiology and Degrade Instrument Cross-Check

• Fatigue or lack of sleep can impair cognitive function and degrade instrument cross-check; ensure adequate rest before flight and recognize signs of fatigue.
• Hypoxia at high altitudes can affect decision-making and instrument monitoring; use supplemental oxygen as needed and monitor cabin altitude.

Spatial Disorientation and Optical Illusions

• Rapid head movements can lead to spatial disorientation and loss of control; avoid abrupt head movements and rely on the flight instruments.
• Optical illusions during approaches, such as false horizons or runway illusions, can mislead pilots; trust and verify the flight instruments and use approach lighting systems.

Flying Unfamiliar Aircraft or Operating with Unfamiliar Flight Displays

• Unfamiliarity with aircraft-specific systems, flight displays, and avionics can lead to improper use and increased safety risks; seek training on new systems.
• Difficulty interpreting flight displays can result in navigation errors and loss of situational awareness; review the manual and become familiar with display functionalities before flight.

Airman Certification Standards for Basic Instrument Maneuvers