How to Use ATR Glass Cockpit Autopilot & Flight Director! | Full Guide
This video provides an overview of the auto flight system in ATR aircraft equipped with glass cockpit. While many functions are similar to those found in legacy ATR aircraft with EFIS cockpit, there are some key differences. Every effort has been made to present the system accurately, but errors may still be present. For information, system failures are not covered in this video. For precise and detailed information, please refer to the Flight Crew Operations Manual
(FCOM). If you spot any errors, feel free to share them in the comments section below. The Autopilot system, or Automatic Flight Control System (AFCS), is made up of the following key components: Two Core Avionics Cabinets, CAC 1 and CAC 2, which control and monitor the auto flight system. One Flight Guidance and Control Panel (FGCP) which is used by the pilots to interact with the auto flight system. Two Index Control Panels (ICP) one for each pilot, which are used
to set target airspeed, altimeter barometric setting, and instrument approach minima. Two Flight Mode Annunciators (FMA) located at the top of each Primary Flight Display (PFD). Vertical and horizontal Flight Director bars on each Attitude Display Indicator (ADI) providing lateral and vertical guidance. Three servo actuators, one for each of the primary flight controls: Elevator,
rudder, and ailerons. One power trim box that interacts with the elevator trim actuator. Two Go Around pushbuttons, one on each power lever. Two Autopilot Quick Disconnect pushbuttons, one on each control wheel. Two Touch Control Steering (TCS) pushbuttons, one on each control wheel. The CACs receive information from two Air Data Computers (ADC), two Attitude and Heading Reference Systems (AHRS), the radio-altimeter, NAV 1&2; they receive VOR and ILS Localizer, both Flight Management Systems (FMS) and from some other aircraft systems. The auto flight system provides the following functions: 1. Flight Director (FD). 2. Autopilot (AP).
3. Automatic pitch trim when the Autopilot is engaged. 4. Yaw Damper (YD) providing turn coordination. 5. Automatic rudder trim when the Yaw Damper is engaged. 6. Altitude alert. The auto flight system is powered by the DC essential bus, DC emergency bus, and DC standby bus, which means it can operate with both DC generators inoperative. However,
in that case some systems are lost, including both DME, VOR/ILS #2, GPS #2, FMS #2, and ICP #2. The general rule is that the autopilot shall only be used when the aircraft is at least 1,000 ft above the ground, except during takeoff and approach. After takeoff, the autopilot can be engaged above 100 ft. For approach, the minimum altitude for using the autopilot or flight director is 160 ft. However, during an ILS Category 2 approach, the autopilot can be used down to 80 ft on the radio altimeter. If an Air Data Computer (ADC) or Attitude Heading Reference System (AHRS) is inoperative, or if both DC generators are inoperative, the autopilot and flight director must not be used when the aircraft is below 1,000 ft above the ground, or when the indicated airspeed is below 160 knots.
When using NAV mode for VOR approach, the use of autopilot or flight director is only allowed when a collocated DME is available, or when DME hold is not selected. This chapter explains the logic and color coding of the flight director modes displayed on the FMA. Lateral modes, such as heading mode and VOR navigation, are shown here, while vertical modes, like indicated airspeed and altitude hold, are shown here. Active modes are displayed
in green color, while armed modes are displayed in cyan color, however, the callout is “blue.” For example, if we are flying in heading select mode with VOR mode armed, the callout is “Heading select green, VOR blue.” The other pilot crosschecks and responds with “Checked.” Once the flight director captures the VOR signal and begins intercepting it, the callout is “VOR star.” The response is “Checked.” A green box will appear for 7 seconds to grab attention.
When the flight director is locked to the VOR, the callout is “VOR green.” The response is “Checked.” Again, a green box will be visible for 7 seconds. Here is another example: You are flying in indicated airspeed (IAS) mode, climbing towards a specific altitude. The callout is “IAS green, ALT SEL blue.” “Checked.” Once the flight director begins issuing commands to level off, the callout is “ALT star.” “Checked.” When the flight director captures the altitude,
the callout is “ALT green.” “Checked.” The flight director's commands are displayed as two green bars on the ADI. Note that it is the flight director that issues the commands, while the autopilot simply follows them. When
flying manually, your task is to follow these commands, which is accomplished when the small square representing the aircraft's fuselage is precisely at the intersection of the two flight director bars. Finally, when a flight director mode is active and you press the pushbutton for that mode for a second time, the flight director reverts to basic mode. For example, if you are climbing in IAS mode and press the IAS pushbutton, the flight director will revert to basic mode, which in this case is pitch hold. The basic modes are explained later. The ATR aircraft operates with two different minimum operating speeds, which are defined as a factor of the stall speed. They depend on aircraft weight, flap setting, phase of flight, and atmospheric conditions (normal or icing). The first speed is the Minimum Speed Low Bank
(VmLB), or low bank speed. It limits the bank angle in turns to 15 degrees. The low bank speed is displayed on the PFD as follows: On the right-side border of the airspeed tape, as the top of an empty amber band extending down to the stick shaker speed, which is presented by the top of the red band. A “LO” label shown in the lateral mode window on the FMA. Two green ticks on the 15 degrees bank indication on the ADI. Low bank speeds are used for take-off, best angle climb, single engine climb, and go-around. Minimum Speed High Bank (VmHB), or high bank speed, limits the bank angle in turns to 27 degrees. High bank speed is 5 to 10 knots higher
than low bank speed. It is displayed on the PFD as follows: The “LO” label is absent. Two green ticks on the 27 degrees bank indication on the ADI. High bank is used for all flight regimes except those specified for low bank. The transition between low bank and high bank occurs automatically. Low bank is selected when the IAS is less than high
bank speed (VmHB), or the radio altimeter is below 1,000 feet. High bank is selected when the IAS exceeds high bank speed + 5 knots, and the radio altimeter is above 1,100 feet. The Flight Guidance Control Panel (FGCP) serves as the primary interface between the pilot and the autoflight system. The panel is divided into three sections, with individual controls for each pilot on either side. The FD pushbuttons toggle the flight director bars on and off on the associated ADI, although the flight director modes remain active.
The CRS and NAV Source controls, will be explained in the navigation mode chapter. In the center of the panel are controls used by both pilots. The Standby (SBY) pushbutton deactivates all active and armed flight director modes. The heading (HDG) knob is used to adjust the heading bug on the navigation display and HSI. Pressing the knob resets the heading bug to the aircraft’s current heading. The altitude select (ALT SEL) knob allows you to preselect the altitude you intend to climb to or descend to. The preselected altitude is displayed in cyan at the top of the altimeter on the PFD,
and as a bug on the altimeter scale. When the aircraft begins climbing or descending towards the selected altitude, altitude select mode is automatically armed. However, if the aircraft is climbing or descending away from the selected altitude, altitude select mode will not be armed. The aircraft is equipped with two VOR/ILS receivers and two Flight Management Systems (FMS). To allow the flight director to determine which navigation source to follow, there are two
controls. The first is the coupling pushbutton (CPL), which toggles between the left and right sides when pressed. The coupling must always be set to the side of the Pilot Flying (PF). When the coupling is set to the left side, the flight director will follow the navigation system selected with the navigation source selector on the captain’s side. In normal operations,
the captain will use FMS #1 and VOR/ILS #1. When the coupling is set to the right side, the flight director will follow the navigation system selected using the navigation source selector on the first officer’s side. In normal operations, the first officer will use FMS #2 and VOR/ILS #2. During an ILS approach, the Flight Director will follow the ILS on the coupled side until reaching 1,200 feet on the radio altimeter. Below 1,200 feet, the Flight Director will use the average signal from both ILS receivers, a mode known as dual coupling.
The coupling selector also determines which Air Data Computer (ADC) and Attitude Heading Reference System (AHRS) the flight director will receive information from. The left row of pushbuttons controls the lateral modes, which manage the vertical flight director bar on the ADI. When no lateral modes are active, the flight director defaults to basic mode, either heading hold or roll hold. Heading hold engages when the bank angle is 6 degrees or less, rolling the aircraft to wings level and maintaining the current heading, regardless of the heading bug’s position. If heading data from the AHRS is not available, the system switches to wings level mode instead.
Roll hold activates when the bank angle exceeds 6 degrees, maintaining the current bank angle or adjusting it to 15 or 27 degrees, depending on whether low bank or high bank is used. The heading (HDG) pushbutton is used to activate heading select (HDG SEL) mode. When heading select is active, the flight director turns to and follows the heading bug. If you turn the heading knob more than 180 degrees, the flight director will not reverse the turn, but continue the turn in the direction initially selected. In normal operation, heading select mode is used in the following situations: 1) Take-off. When the aircraft is lined up on the runway, the heading knob is pushed to center the heading bug and the vertical flight director bar.
2) When following radar vectors from ATC. 3) When intercepting localizer or VOR radials without using the FMS. 4) During initial phase of a go-around. 5) When you temporarily want to deviate from your flight plan, for example to circumnavigate thunderstorms. 6) When flying visual patterns. En-route navigation can be conducted using the FMS, VOR, or NDB as the navigation source.
When the navigation source is set to FMS, and the NAV pushbutton is selected, the flight director follows the active flight plan in the associated FMS, engaging lateral navigation (LNAV). However, GPS signals can fail or be jammed. While the FMS has a DME/DME backup, its accuracy is reduced in such cases. If the FMS is compromised, VOR is the preferred alternative. The navigation source is switched to VOR/ILS,
the correct frequency is tuned, and the course is set to the appropriate radial on the HSI. If the VOR lacks a collocated DME, the flight director may overcorrect near the station, requiring the use of heading (HDG) mode instead. Heading mode is also used when navigating with the ADF. A 2-dimensional (2D) approach is an instrument approach that provides lateral guidance but, unlike a 3-dimensional (3D) approach, does not include vertical guidance. Instead, the Vertical Speed (VS) mode is used to manage the descent profile.
The types of 2D approaches include: LNAV approach. VOR/DME approach. VOR approach. NDB approach. Localizer or LDA approach. Localizer back course approach. An LNAV approach is an RNAV or RNP approach where lateral guidance is provided by the FMS. A VOR/DME approach can be flown either using the VOR receiver and HSI or with LNAV, provided that the Pilot Monitoring (PM) cross-checks the VOR on the HSI and confirms the aircraft remains within ±5 degrees of the approach course. A VOR approach without a collocated DME cannot
be flown using the auto flight system in VOR navigation mode. Without knowing the distance, the flight director cannot calculate the correct heading corrections to intercept and track the VOR radial. Instead, you must use Heading (HDG) mode, or you can use FMS in LNAV mode, with the PM is monitoring the VOR on the HSI. An NDB approach can be flown in Heading (HDG) mode using the bearing needle on the HSI as a reference. It can also be flown using LNAV, provided that the PM monitors the NDB bearing and confirms the aircraft remains within ±5 degrees of the approach course. A Localizer approach can only be
flown in Localizer (LOC) mode because the obstacle-sensitive area near the runway is narrower than the 0.3 NM corridor used by the FMS. A Localizer-Type Directional Aid (LDA) approach is a localizer-based approach that is not aligned with the runway centerline. The BC pushbutton is used to arm the localizer back course mode. A localizer back course approach is an instrument approach procedure that utilizes the localizer signal in the reverse direction. Here is an example: At Waterloo Regional Airport, in Iowa, United States, there is an ILS approach to Runway 12 with a frequency of 111.7 MHz and a collocated
DME. The approach course is 128 degrees. For Runway 30, a localizer back course approach is published. This procedure uses the same frequency (111.7 MHz) as the ILS for Runway 12, but the approach track is 308 degrees. However, an important detail not immediately evident on the chart is that when flying a back course, the course selector on the HSI must be set to the opposite course (128 degrees). If the course selector is incorrectly set to 308 degrees, the deviation bar on the HSI will reverse, causing it to deflect in the wrong direction and misleading the pilot to steer away from the localizer beam rather than toward it. Warning: Never fly a localizer back course unless it is certified by the relevant authority. Attempting to improvise your own procedure is unsafe, as the localizer back beam
is not calibrated, and there is no guarantee that the approach meets safety standards. Approach (APP) mode is used to select one of the following 3D approaches: 1. ILS approach. 2. LNAV/VNAV approach. 3. LPV approach. When flying an ILS approach, pressing the APP pushbutton arms both the Localizer (LOC) and the Glide Slope (GS). The glideslope can only be captured after the localizer is captured. If localizer mode is
deselected after the glideslope is captured, the vertical mode will revert to pitch hold. Once the glideslope is captured, altitude select mode is inhibited, allowing you to set the published go-around altitude. When flying an RNAV or RNP approach, the initial modes are LNAV mode and either in VNAV or altitude hold mode. Pressing the APP pushbutton arms the Vertical Flight Path (V-FP) mode.
When the aircraft is 2 NM of the Final Approach Fix, V-FP becomes active, and the flight director will follow the published vertical profile for the approach. In many ways, V-FP functions very similar to an ILS glideslope: When active, ALT select mode is inhibited, and you can set the published go-around altitude. Localizer Performance with Vertical Guidance (LPV) is an RNP approach providing a level of precision similar to an ILS. This is achieved by utilizing Satellite Based Augmentation System (SBAS). In North America it is known as Wide Area Augmentation System (WAAS). In Europe, it is known as EGNOS. In India, GAGAN. And in East Asia, MSAS.
Ground stations across each area monitor GPS signals and compute a correction signal that is transmitted to a geo-stationary satellite, which transmits the signal to the aircraft. For example, this is the chart for RNP approach to runway 14R at Toulouse, France. The EGNOS channel is 57314. The decision height for an ATR, category B, is 230 feet. In comparison, LNAV/VNAV has a decision height of 410 feet, and LNAV a minimum descent height of 460 feet.
Note: Minima for a 3D approach is given as decision altitude or height, while minima for a 2D approach is given as minimum descent altitude or height. This type of approach requires installation of additional equipment in the aircraft. When the aircraft is cleared for approach, the approach (APP) pushbutton is pressed. This
arms L-LOC and L-GS modes. They behave like an ILS localizer and glideslope. The right row of pushbuttons is for vertical modes. They control the horizontal flight director bar on the ADI. When no vertical modes are active, the flight director is in pitch hold mode, which means it maintains the aircraft’s current pitch attitude. The pitch wheel is used to adjust the pitch target, which is shown by the horizontal flight director bar.
The Indicated Air Speed (IAS) pushbutton activates IAS hold mode, which is the standard vertical mode for takeoff and climb. Standard climb speed is 160 knots for the ATR 42 and 170 knots for the ATR 72. IAS mode is also used during an emergency descent. When IAS mode is active, the flight director commands a pitch that allows the aircraft to capture and maintain the indicated airspeed displayed at the top of the airspeed indicator. If the speed is shown in magenta, it is managed by the FMS. If the speed is shown in cyan, it is manually managed by the pilot,
who adjusts the speed using the speed target knob on the Index Control Panel (ICP). The pilot can switch between automatic and manual control using the AUTO/MAN select pushbutton. If the aircraft is in level flight, a new target altitude must be selected with the ALT SEL knob before IAS mode is selected. Otherwise, the flight director will revert to ALT HOLD. The target indicated air speed is also indicated with a bug on the Air Speed Indicator, ASI. The color is the same as the numeric value. The VS pushbutton activates Vertical Speed (VS) hold mode. When VS mode is active, the rate of climb or descent is controlled using the pitch wheel. VS mode is primarily intended for descent,
but it can also be used in climb when performance is good and the aircraft is about to level off. If the aircraft is in level flight, a new target altitude must be set using the ALT SEL knob before selecting VS mode. Otherwise, the flight director will revert to ALT HOLD. The target vertical speed is displayed with a bug on the Vertical Speed Indicator (VSI), and the color matches the numeric value. The VNAV pushbutton activates Vertical Navigation (VNAV) mode.
VNAV was introduced with Standard 3 software, so early 600 variants do not have this pushbutton or function unless they have been upgraded. Note: VNAV is only available when LNAV is active. There are four VNAV modes; two for climb and two for descent. The first mode is VNAV IAS. It can be armed before takeoff but can also be activated in flight during a climb, or in level flight, to initiate a climb.
The purpose of VNAV IAS is to ensure the aircraft does not exceed altitude constraints on a Standard Instrument Departure (SID). Some SIDs require the aircraft to cross a waypoint at or below a specific altitude. On this chart one waypoint must be crossed at or below 6,000 feet, and two other waypoints at or below 9,000 feet. VNAV IAS helps manage this. When the aircraft is cleared by ATC to climb to a higher altitude than the altitude constraint, and the cleared altitude is set in the ALT SEL window, the FMS calculates the altitude the aircraft will have when crossing the waypoint. If the aircraft is expected to reach the
altitude constraint before the waypoint, the flight director will arm VNAV ALT, and the altitude constraint will be displayed in magenta next to ALT SEL. VNAV ALT overrides the altitude set in ALT SEL, and the flight director will command the aircraft to level off at the assigned altitude. When VNAV ALT is active, VNAV IAS is armed. When passing the waypoint, VNAV IAS becomes active again, and the aircraft will resume climbing. Although many SIDs do not have "Cross at or below" altitude constraints, it is considered good operating practice to arm VNAV IAS before every takeoff when LNAV is used for navigation.
Before starting the descent, ALT SEL must be set to an altitude below the aircraft's current altitude. Five minutes before reaching the Top of Descent (TOD), the vertical deviation indicator will appear on the ADI. If the VNAV pushbutton is pressed before the vertical deviation indicator is visible, VNAV VS mode will activate, and the aircraft will begin descending at a rate of 1,500 feet per minute. If the VNAV pushbutton is pressed when the vertical deviation indicator is visible, VNAV PATH mode is activated.
When the VNAV pushbutton is pressed before reaching Top of Descent (TOD), the FMS calculates a new vertical path from the aircraft's current position to the first waypoint with an altitude constraint. As a result, the vertical path will be shallower than the standard 3-degree descent until reaching the waypoint with the altitude constraint. When the VNAV pushbutton is pressed after passing the Top of Descent, the FMS commands a 5.5-degree
descent path until it intercepts the nominal 3-degree path. This results in a descent rate of approximately 2,800 feet per minute, which can make speed control difficult. Therefore, if you overshoot the Top of Descent, a better option is to use VS mode set to a descent rate of -1,800 to -2,000 feet per minute until capturing the normal descent profile. The ALT pushbutton activates Altitude Hold mode. It is rarely used,
as ALT Select mode is automatically armed when climbing or descending toward the selected altitude. However, Altitude Hold is useful when ATC instructs you to level off at an altitude near your current altitude during a climb or descent. When one of the go-around pushbuttons is pressed, the flight director switches to Heading Hold (HDG HOLD) and Go-Around (GA) mode. The pitch
command is based on the flaps setting and provides a minimum safe pitch-up attitude. Once the landing gear is selected up, the procedure is to select Heading Select (HDG SEL) mode and IAS mode. When the missed approach procedure in the FMS is confirmed, LNAV mode is engaged. If LNAV was already engaged when the go-around pushbutton was pressed, LNAV remains active to guide the missed approach procedure.
The Touch Control Steering, TCS pushbutton on the back side of the control wheel enables the pilot to take temporary manual control of the aircraft without disconnecting the AP. A green TCS label is displayed on the FMA when used. The TCS can be used to: Adjust pitch and roll in basic mode. And adjust rate of climb or descent in VS mode. The Autopilot and Yaw Damper pushbuttons are used to engage and disengage their respective functions. The Yaw Damper enhance passenger comfort and provide automatic rudder trim. It is engaged when the landing gear is retracted and is switched off before landing. It is crucial to turn off the yaw damper before landing due to its automatic rudder trim function. If you forget to disconnect the yaw damper, the rudder trim will counteract your
rudder inputs during landing. A good operational practice is to turn off the Yaw Damper when the autopilot is disengaged and the aircraft is below 500 feet on the radio altimeter. The autopilot follows the commands from the flight director and provides automatic pitch trim. The autopilot will only operate when the yaw damper is engaged. The engagement sequence is as follows: When the yaw damper is selected ON, it engages. When the autopilot is selected ON,
both the autopilot and yaw damper engage. When the autopilot is selected OFF, the autopilot disengages, but the yaw damper remains ON. When the yaw damper is selected OFF, both the autopilot and yaw damper disengage. The autopilot can be manually disconnected by pressing the autopilot pushbutton, using the quick disconnect button on the control wheel, pressing one of the go-around pushbuttons on the power levers, activating pitch trim, or applying excessive force on the flight controls. The autopilot will also disconnect automatically if there is a discrepancy between the air data computers, the attitude heading reference systems, or due to some other system failures. A full description of these conditions is provided in the FCOM.
The Speed Hold pushbutton is not active. It was intended to provide an auto-power capability for ILS Category 3 approaches. However, no airline has opted to include this function, as the development and certification costs outweigh the operational benefits. As a result, this pushbutton is non-functional. The altitude alert is an aural "C chord" lasting for 1 second. It is triggered in the following situations: 1. When the aircraft passes 1,000 feet before reaching the pre-selected altitude during climb or descent.
2. When the aircraft deviates more than 250 feet from the pre-selected altitude. The altimeter box will flash amber when the aircraft’s altitude is between 1,000 feet and 250 feet of the pre-selected altitude. When LNAV is in use and the aircraft is 1 minute from the Top of Descent (TOD), the Vertical Track Alert (VTA) is triggered by flashing the selected altitude and its bug, and the magenta “V” on top of the vertical deviation indicator. The alert ends when ALT SEL has been modified by the crew. When the vertical gradient will change at a waypoint, the Vertical Path Change Alert (VPCA) is triggered by flashing the vertical deviation indicator, and the magenta vertical speed and its bug, 10 seconds before the pitch change will take place. The Flight Path Angle Protection system was introduced with the Standard 3.1 software. The purpose is to prevent the aircraft from stopp climbing after take-off or go-around, or when encountering significant downdrafts.
The Flight Path Angle Protection system is available in the following situations: 1. In Indicated Air Speed (IAS) mode for 180 seconds after liftoff. 2. In Go-Around mode for 180 seconds when the radio altimeter is less than 500 ft. 3. In VNAV IAS mode. This is a good reason for arming VNAV IAS before every take-off. When the Flight Path Angle Protection system is active, the auto flight system controls pitch directly. If the Flight Path Angle
Protection system is active for more than 20 seconds and the speed is less than high bank speed (VmHB), PITCH HOLD mode is activated, together with a 3 click audio alert. This gives the flight crew time to assess the situation and select the best sequence of actions, for example select Altitude hold to retrieve acceleration capability. The purpose of the High Speed Protection is to prevent the aircraft from exceeding the maximum operating speed. It is available when the autopilot is engaged, and VNAV PATH, VNAV VS,
VS, ALT star, or PITCH HOLD modes are engaged in descent with flaps retracted or flaps 15. When the airspeed is approaching the maximum operating speed, the auto flight system takes over and reduces the descent rate, possibly down to zero. When the High Speed Protection has been active for more than 3 or 6 seconds, depending on the flaps configuration, a 3 click audio alert is triggered together with a “REDUCE SPEED” label on the FMA. The purpose of the Low Speed Protection is to prevent the aircraft speed from decreasing significantly below minimum operating speed. When active, the auto flight system takes over pitch guidance and alerts the flight crew. Low Speed Protection is available when
the autopilot is engaged, and VNAV ALT star, ALT star, VS or PITCH HOLD modes are engaged in climb with flaps retracted or flaps 15. If the airspeed approaches the minimum operating speed, the auto flight system starts to control pitch, and 3 seconds later “MONITOR SPEED” is displayed on the FMA. When the vertical speed reaches 0 feet per minute while low speed protection is active, the active vertical mode is replaced by Protection Level (PROT LEVEL) mode, maintaining a vertical speed at 0 feet per minute. The purpose of the complementary low speed alerting is to alert the flight crew that the aircraft speed decreases significantly below minimum operating speed, V min ops.
The alert is available in flight, above 80 ft, and consists of 3 click audio alert and a SPEED SPEED message on the FMA. However, the auto flight system does not intervene. With flaps 0 or flaps 15, and protection level is not engaged, the alert is triggered when the indicated airspeed decreases to minimum operating airspeed -5 knots. With landing flaps, and protection level is not engaged, the alert is triggered when the indicated airspeed decreases to minimum operating airspeed -3 knots.
When protection level is active, the alert is triggered when the indicated airspeed decreases to minimum operating airspeed +1 knot. This concludes the video about the auto flight system in ATR aircraft with glass cockpit. Please note that some software variants may not include all functions described here. Furthermore, the functions have not been explained in full detail. Always refer to the FCOM of the specific aircraft you are flying for accurate information. Thank you for watching.
2025-04-04 01:36
