Turn Coordinator: How It Works, Indications, & Limitations

Turn Coordinator

Introduction to Turn Coordinator

Turn coordinators display the rate of turn and roll information.
Designed to function off an electrically or vacuum/pressure driven gyroscope, indicating the quality and coordination of a turn.
Pilots monitor the instrument's performance on startup and taxi to ensure proper function.
Newer aircraft utilize modern Inertial Reference Unit (IRU), Inertial Navigation System (INS), and Attitude Heading Reference System (AHRS) systems for glass displays.
As with any system or instrument, anomalies and malfunctions are possible, requiring detailed knowledge of the indicator and related systems.
Test your understanding of Turn Coordinator by completing the knowledge quiz, applying your knowledge in the interactive scenario, comparing your performance against the applicable Airman Certification Standards, and concluding with the topic summary to reinforce the key concepts before moving on to the next lesson.

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Turn Coordinator

Turn Coordinator Key Highlights

The turn coordinator displays aircraft rate of turn and roll information during flight operations.
Turn coordinators use gyroscopic principles to sense both roll initiation and turning motion.
The miniature aircraft symbol indicates the direction and rate of turn relative to standard-rate turn markings.
Standard-rate turns normally result in a heading change of approximately three degrees per second.
The inclinometer, or slip-skid indicator, helps pilots maintain coordinated flight by showing balance between centrifugal force and gravity.
An aircraft in coordinated flight keeps the inclinometer ball centered during turns and maneuvering operations.
Turn coordinators are especially important during instrument flight and reduced-visibility conditions.
Vacuum system failures or electrical malfunctions may affect turn coordinator operation depending on aircraft design.
Pilots should cross-check turn coordinator indications with other flight instruments to maintain proper aircraft control.
Understanding turn coordinator operation improves instrument proficiency, coordinated flight control, and overall flight safety.

Turn Coordinator

Turn Coordinator Design and Function

Turn Coordinator
Turn and Slip Indicator
Turn coordinators provide turn performance indications with a gyroscope. []

To maintain accuracy, the gyroscope is mounted at a 30° angle.

The gyro is either electrically or vacuum/pressure driven
Developed from the turn and bank indicator
When the aircraft yaws, or rotates about its vertical axis, it produces a force in the horizontal plane that, due to precession, causes the gyro and its gimbal to rotate about the gimbal's axis
It is restrained in this rotation plane by a calibration spring; it rolls over just enough to cause the pointer to deflect until it aligns with one of the doghouse-shaped marks on the dial, when the aircraft is making a standard rate turn
A red flag shows the instrument is in a non-operational status
Inclinometer is located below the instrument used to determine quality of a turn (angle of bank and the rate of yaw)
The words printed 2-minutes means a standard rate turn held for 2-minutes would result in a 360° turn
This ball measures the relative strength of the force of gravity and the force of inertia caused by a turn
Gyroscopically driven using the principle of precession
A line indicates the standard rate turn
Mounted with about a 30 - 35° canted on the gyro
The gyro is mounted in a single gimbal with its spin axis parallel to the lateral axis of the aircraft and the axis of the gimbal parallel with the longitudinal axis
Slip: rate of turn is too slow for the angle of bank
Skid: rate of turn is too great for the angle of bank
The turn and slip indicator is an older design, and provides rate of turn and roll information. []
- Because the gyro is mounted along the aircraft's longitudinal axis, yaw and roll information are not provided
- Turn & slip indicators therefore only show rate of turn.
Turn Coordinator
Turn and Slip Indicator

Turn Coordinator

Turn Coordinator Indications

Turn coordinators precisely indicate the quality of turn, and generally the rate-of-turn.
Specific rate of turn indications relate to standard rate turns:
- When the miniature aircraft (or the needle is straight up and down), the aircraft is straight and level
- When the miniature aircraft (or needle) is aligned with one of the turn alignment marks, it is in a standard rate turn
- A standard rate turn is defined as an aircraft turning at 3° per second
- This standard turn rate is dependent upon True Airspeed and so the faster an aircraft is moving, the more angle of bank is required to achieve this set 3° rate
- SRT Angle of Bank = [True Airspeed in Knots / 10] + 7

Turn Coordinator

Turn Coordinator Preflight Actions

Upon engine start and the activation of the gyroscopes (vacuum or electrical system), any flags should disappear.
As the aircraft begins to taxi, the aircraft should indicate a bank in the direction of taxi turns and the ball inside the inclinometer should deflect outward from the turn.

Turn Coordinator

Inertial Reference Unit (IRU), Inertial Navigation System (INS), and Attitude Heading Reference System (AHRS)

IRUs are self-contained systems comprised of gyros and accelerometers that provide aircraft attitude (pitch, roll, and heading), position, and velocity information in response to signals resulting from inertial effects on system components.
- Once aligned with a known position, IRUs continuously calculate position and velocity. IRU position accuracy decays with time.
- This degradation is known as "drift."
INSs combine the components of an IRU with an internal navigation computer.
- By programming a series of waypoints, these systems will navigate along a predetermined track.
AHRSs are electronic devices that provide attitude information to aircraft systems such as weather radar and autopilot, but do not directly compute position information.
Aircraft equipped with slaved compass systems may be susceptible to heading errors caused by exposure to magnetic field disturbances (flux fields) found in materials that are commonly located on the surface or buried under taxiways and ramps.
- These materials generate a magnetic flux field that can be sensed by the aircraft's compass system flux detector or "gate", which can cause the aircraft's system to align with the material's magnetic field rather than the earth's natural magnetic field.
- The system's erroneous heading may not self-correct.
- Prior to take off pilots should be aware that a heading misalignment may have occurred during taxi.
- Pilots are encouraged to follow the manufacturer's or other appropriate procedures to correct possible heading misalignment before take off is commenced.

Turn Coordinator

Turn Coordinator Anomalies & Malfunctions

Turn Coordinator

Turn Coordinator Interactive Scenario

Interactive Scenario

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Scenario Complete

Turn Coordinator

Turn Coordinator Knowledge Check

Choose the knowledge check that matches your current training for Turn Coordinator.

Private Pilot

PPL knowledge check

Core Knowledge Review

Review foundational knowledge, key concepts, and practical considerations. Topic: Turn Coordinator.

Immediate feedback
Answer explanations
Account progress tracking

Why Take a Quiz?

Quizzes reinforce key concepts, identify knowledge gaps, and build confidence for real-world decisions. Quiz material is representative of the information provided here and is not based on or sourced from the Federal Aviation Administration test bank.

Turn Coordinator

Turn Coordinator-Related Airman Certification Standards

Private Pilot (Airplane) Operation of Aircraft Systems Airman Certification Standards

Objective: To determine whether the applicant exhibits satisfactory knowledge, risk management, and skills associated with safe operation of systems on the airplane provided for the flight test.
References: FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-23 (Seaplane, Skiplane, and Float/Ski Equipped Helicopter Operations Handbook), FAA-H-8083-25 (Pilot Handbook of Aeronautical Knowledge); POH/AFM.
Note: If K1 is selected, the evaluator must assess the applicant's knowledge of at least three sub-elements
Private Pilot (Airplane) Operation of Aircraft Systems Lesson Plan.

Knowledge 2 ACS Elements

PA.I.G.K1:
Airplane systems, including:
- PA.I.G.K1a:
  Primary flight controls.
- PA.I.G.K1a:
  Secondary flight controls.
- PA.I.G.K1c:
  Powerplant and propeller.
- PA.I.G.K1d:
  Landing gear.
- PA.I.G.K1e:
  Fuel, oil, and hydraulic.
- PA.I.G.K1f:
  Electrical.
- PA.I.G.K1g:
  Avionics.
- PA.I.G.K1h:
  Pitot-static, vacuum/pressure, and associated flight instruments.
- PA.I.G.K1i:
  Environmental.
- PA.I.G.K1j:
  Deicing and anti-icing.
- PA.I.G.K1k:
  Water Rudders (ASES, AMES).
- PA.I.G.K1l:
  Oxygen Systems.
PA.I.G.K2:
Indications of and procedures for managing system abnormalities or failures.

Risk Management 3 ACS Elements

PA.I.G.R1:
Detection of system malfunctions or failures.
PA.I.G.R2:
Management of a system failure.
PA.I.G.R3:
Monitoring and management of automated systems.

Skills 2 ACS Elements

PA.I.G.S1:
Operate at least three of the systems listed in K1a through K1l appropriately.
PA.I.G.S2:
Complete the appropriate checklist(s).

Private Pilot (Helicopter) Operation of Systems Airman Certification Standards

Area of Operation I: Preflight Preparation.
Task G: Operation of Systems.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with safe operation of systems on the helicopter provided for the flight test.
Note: If K1 is selected, the evaluator must assess the applicant's knowledge of at least three sub-elements.
References: FAA-H-8083-2, FAA-H-8083-21, FAA-H-8083-25; POH/RFM
Private Pilot (Helicopter) Operation of Systems Lesson Plan.

Knowledge 2 ACS Elements

PH.I.G.K1:
Helicopter systems, including:
- PH.I.G.K1a:
  a. Flight controls, trim, and if installed, stability control
- PH.I.G.K1b:
  b. Powerplant(s)
- PH.I.G.K1c:
  c. Main rotor and antitorque systems
- PH.I.G.K1d:
  d. Transmission and associated drive shafts
- PH.I.G.K1e:
  e. Fuel, oil, and hydraulic
- PH.I.G.K1f:
  f. Avionics
- PH.I.G.K1g:
  g. Landing gear, brakes, steering, skids, or floats, as applicable
- PH.I.G.K1h:
  h. Electrical
- PH.I.G.K1i:
  i. Pitot-static, vacuum/pressure, and associated flight instruments
- PH.I.G.K1j:
  j. Environmental
- PH.I.G.K1k:
  k. Anti-icing and deicing, including carburetor heat, if applicable
PH.I.G.K2:
Indications of and procedures for managing system abnormalities or failures.

Risk Management 3 ACS Elements

PH.I.G.R1:
Detection of system malfunctions or failures.
PH.I.G.R2:
Management of a system failure.
PH.I.G.R3:
Monitoring and management of automated systems.

Skills 2 ACS Elements

PH.I.G.S1:
Operate at least three of the helicopter's systems listed in K1a through K1k.
PH.I.G.S2:
Complete the appropriate checklist(s).

Private Pilot (Airplane) Systems and Equipment Malfunctions Airman Certification Standards

Objective: To determine whether the applicant exhibits satisfactory knowledge, risk management, and skills associated with system and equipment malfunctions appropriate to the airplane provided for the practical test
References: FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-25 (Pilot Handbook of Aeronautical Knowledge); POH/AFM.
Private Pilot (Airplane) Systems and Equipment Malfunctions Lesson Plan.

Knowledge 15 ACS Elements

PA.IX.C.K1:
Causes of partial or complete power loss related to the specific type of powerplant(s).
- PA.IX.C.K1a:
  [Archived].
- PA.IX.C.K1b:
  [Archived].
- PA.IX.C.K1c:
  [Archived].
- PA.IX.C.K1d:
  [Archived].
PA.IX.C.K2:
System and equipment malfunctions specific to the aircraft, including:
- PA.IX.C.K2a:
  Electrical malfunction.
- PA.IX.C.K2b:
  Vacuum/pressure and associated flight instrument malfunctions.
- PA.IX.C.K2c:
  Pitot/static system malfunction.
- PA.IX.C.K2d:
  Electronic flight deck display malfunction.
- PA.IX.C.K2e:
  Landing gear or flap malfunction.
- PA.IX.C.K2f:
  Inoperative trim.
PA.IX.C.K3:
Causes and remedies for smoke or fire onboard the aircraft.
PA.IX.C.K4:
Any other system specific to the airplane (e.g., supplemental oxygen, deicing).
PA.IX.C.K5:
Inadvertent door or window opening.

Risk Management 4 ACS Elements

PA.IX.C.R1:
Checklist usage for a system or equipment malfunction.
PA.IX.C.R2:
Distractions, task prioritization, loss of situational awareness, or disorientation.
PA.IX.C.R3:
Undesired aircraft state.
PA.IX.C.R4:
Startle response.

Skills 2 ACS Elements

PA.IX.C.S1:
Describe appropriate action for simulated emergencies specified by the evaluator, from at least three of the elements or sub-elements listed in K1 through K5 above.
PA.IX.C.S2:
Complete the appropriate checklist(s).

Private Pilot (Helicopter) Systems and Equipment Malfunctions Airman Certification Standards

Area of Operation VIII: Emergency Operations.
Task D: Systems and Equipment Malfunctions.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with causes, indications, and pilot actions for system malfunctions.
References: AIM; FAA-H-8083-2, FAA-H-8083-21, FAA-H-8083-25
Private Pilot (Helicopter) Systems and Equipment Malfunctions Lesson Plan.

Knowledge 5 ACS Elements

PH.VIII.D.K1:
Causes of partial or complete power loss related to the specific type of powerplant(s).
PH.VIII.D.K2:
System and equipment malfunctions specific to the helicopter, including:
- PH.VIII.D.K2a:
  a. Electrical malfunction
- PH.VIII.D.K2b:
  b. Flight instrument malfunctions
- PH.VIII.D.K2c:
  c. Pitot-static system malfunction
- PH.VIII.D.K2d:
  d. Electronic flight deck display malfunction
- PH.VIII.D.K2e:
  e. Landing gear malfunctions
- PH.VIII.D.K2f:
  f. Inoperative flight control/trim
- PH.VIII.D.K2g:
  g. Hydraulic failure, if applicable
PH.VIII.D.K3:
Various frequency vibrations and the possible components that may be affected.
PH.VIII.D.K4:
Causes and remedies for smoke or fire onboard the aircraft.
PH.VIII.D.K5:
Any other system malfunction specific to the helicopter flown.

Risk Management 4 ACS Elements

PH.VIII.D.R1:
Startle response.
PH.VIII.D.R2:
Checklist usage for a system or equipment malfunction.
PH.VIII.D.R3:
Distractions, task prioritization, loss of situational awareness, or disorientation.
PH.VIII.D.R4:
Undesired aircraft state.

Skills 2 ACS Elements

PH.VIII.D.S1:
Determine appropriate action for simulated emergencies specified by the evaluator, from at least three of the elements or sub-elements listed in K1 through K5.
PH.VIII.D.S2:
Complete the appropriate checklist(s).

Instrument Rating (Airplane) Aircraft Flight Instruments and Navigation Equipment Airman Certification Standards

Objective: To determine whether the applicant exhibits satisfactory knowledge, risk management, and skills associated with managing instruments appropriate for an IFR flight.
References: 14 CFR part 91; AC 90-100, AC 90-105, AC 90-107, AC 91-78, AC 91.21-1; AIM; FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-15, and FAA-H-8083-25 (Pilot's Handbook of Aeronautical Knowledge).
Instrument Rating (Airplane) Aircraft Flight Instruments and Navigation Equipment Lesson Plan.

Knowledge 3 ACS Elements

IR.II.B.K1:
Operation of the aircraft's applicable flight instrument system(s), including:
- IR.II.B.K1a:
  Pitot-static instrument system and associated instruments.
- IR.II.B.K1b:
  Gyroscopic/electric/vacuum instrument system and associated instruments.
- IR.II.B.K1c:
  Electrical systems, electronic flight instrument displays [primary flight display (PFD), multifunction display (MFD)], transponder, and automatic dependent surveillance-broadcast (ADS-B).
- IR.II.B.K1d:
  Magnetic compass.
IR.II.B.K2:
Operation of the aircraft's applicable navigation system(s), including:
- IR.II.B.K2a:
  Very high frequency (VHF) Omnidirectional Range (VOR), distance measuring equipment (DME), instrument landing system (ILS), and marker beacon receiver/indicators.
- IR.II.B.K2b:
  Area navigation (RNAV), global positioning system (GPS), Wide Area Augmentation System (WAAS), flight management system (FMS), and autopilot.
IR.II.B.K3:
Use of an electronic flight bag (EFB), if used.

Risk Management 5 ACS Elements

IR.II.B.R1:
Monitoring and management of automated systems.
IR.II.B.R2:
Difference between approved and non-approved navigation devices.
IR.II.B.R3:
Modes of flight and navigation instruments, including failure conditions.
IR.II.B.R4:
Use of an electronic flight bag.
IR.II.B.R5:
Use of navigation databases.

Skills 2 ACS Elements

Sport Pilot (Helicopter) Systems and Equipment Malfunctions Airman Certification Standards

Area of Operation VIII: Emergency Operations.
Task D: Systems and Equipment Malfunctions.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with Sport Pilot for Helicopter - Simplified Flight Controls ACS (FAA-S-ACS-26) 42 Area of Operation VIII. Emergency Operations causes, indications, and pilot actions for system malfunctions.
References: AIM; FAA-H-8083-2, FAA-H-8083-21, FAA-H-8083-25; VFR Navigation Charts
Sport Pilot (Helicopter) Systems and Equipment Malfunctions Lesson Plan.

Knowledge 5 ACS Elements

SH.VIII.D.K1:
Causes of partial or complete power loss related to the specific type of powerplant(s).
SH.VIII.D.K2:
System and equipment malfunctions specific to the helicopter-simplified flight controls, including:
- SH.VIII.D.K2a:
  Electrical malfunction
- SH.VIII.D.K2b:
  Flight instrument malfunctions
- SH.VIII.D.K2c:
  Pitot-static system malfunction
- SH.VIII.D.K2d:
  Electronic flight deck display malfunction
- SH.VIII.D.K2e:
  Landing gear malfunctions, as applicable
- SH.VIII.D.K2f:
  Inoperative simplified flight controls/trim, as applicable
- SH.VIII.D.K2g:
  Hydraulic failure, as applicable
SH.VIII.D.K3:
Various frequency vibrations and the possible components that may be affected.
SH.VIII.D.K4:
Causes and remedies for smoke or fire onboard the aircraft.
SH.VIII.D.K5:
Any other system malfunction specific to the helicopter-simplified flight controls flown.

Risk Management 4 ACS Elements

SH.VIII.D.R1:
Startle response.
SH.VIII.D.R2:
Checklist usage for a system or equipment malfunction, as applicable.
SH.VIII.D.R3:
Distractions, task prioritization, loss of situational awareness, or disorientation.
SH.VIII.D.R4:
Undesired aircraft state.

Skills 2 ACS Elements

SH.VIII.D.S1:
Determine appropriate action for simulated emergencies specified by the evaluator, from at least three of the elements or sub-elements listed in K1 through K5.
SH.VIII.D.S2:
Complete the appropriate checklist(s).

Sport Pilot (Helicopter) Operation of Systems Airman Certification Standards

Area of Operation I: Preflight Preparation.
Task G: Operation of Systems.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with safe operation of systems on the helicopter-simplified flight controls provided for the flight test.
References: AIM; FAA-H-8083-2, FAA-H-8083-21, FAA-H-8083-25; POH/RFM
Sport Pilot (Helicopter) Operation of Systems Lesson Plan.

Knowledge 2 ACS Elements

SH.I.G.K1:
Helicopter-Simplified Flight Control systems, including:
- SH.I.G.K1a:
  Flight controls, trim, and if installed, stability control
- SH.I.G.K1b:
  Powerplant(s)
- SH.I.G.K1c:
  Main rotor(s) and antitorque systems, as applicable
- SH.I.G.K1d:
  Transmission and associated drive shafts
- SH.I.G.K1e:
  Fuel, oil, and hydraulic
- SH.I.G.K1f:
  Avionics
- SH.I.G.K1g:
  Landing gear, brakes, steering, skids, or floats, as applicable
- SH.I.G.K1h:
  Electrical
- SH.I.G.K1i:
  Pitot-static, vacuum/pressure, and associated flight instruments
- SH.I.G.K1j:
  Environmental
- SH.I.G.K1k:
  Anti-icing and deicing, including carburetor heat, as applicable
SH.I.G.K2:
Indications of and procedures for managing system abnormalities or failures.

Risk Management 3 ACS Elements

SH.I.G.R1:
Detection of system malfunctions or failures.
SH.I.G.R2:
Management of a system failure.
SH.I.G.R3:
Monitoring and management of automated systems.

Skills 2 ACS Elements

SH.I.G.S1:
Operate at least three of the helicopter-simplified flight control’s systems listed in K1a through K1k.
SH.I.G.S2:
Complete the appropriate checklist(s).

Turn Coordinator

Turn Coordinator Conclusion

Always keep in mind the effects of parallax error.
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Turn Coordinator

Turn Coordinator References

Instrument Flight Knowledge and Decisions

It responds to roll and turn rate; its deflection does not directly measure bank angle. Use the appropriate attitude reference for bank and the turn indication to cross-check the turning response.

Supporting references: FAA guidance.

Turn Coordinator

Introduction to Turn Coordinator

Turn Coordinator Key Highlights

Turn Coordinator Design and Function

Turn Coordinator Indications

Turn Coordinator Preflight Actions

Inertial Reference Unit (IRU), Inertial Navigation System (INS), and Attitude Heading Reference System (AHRS)

Turn Coordinator Anomalies & Malfunctions

Turn Coordinator Interactive Scenario

Interactive Scenario

Scenario Complete

Turn Coordinator Knowledge Check

Core Knowledge Review

Sport Pilot Knowledge

Advanced Application

Instrument Knowledge

Instructor Knowledge

Instrument Instructor Knowledge

Why Take a Quiz?

Private Pilot (Airplane) Operation of Aircraft Systems Airman Certification Standards

Private Pilot (Helicopter) Operation of Systems Airman Certification Standards

Private Pilot (Airplane) Systems and Equipment Malfunctions Airman Certification Standards

Private Pilot (Helicopter) Systems and Equipment Malfunctions Airman Certification Standards

Instrument Rating (Airplane) Aircraft Flight Instruments and Navigation Equipment Airman Certification Standards

Sport Pilot (Helicopter) Systems and Equipment Malfunctions Airman Certification Standards

Sport Pilot (Helicopter) Operation of Systems Airman Certification Standards

Turn Coordinator Conclusion

Turn Coordinator References

Instrument Flight Knowledge and Decisions