ATR 42/72-600 Systems Guide — Chapter Q: Power Plant

2026-06-23

Chapter Q. POWER PLANT (FCOM DSC 71, 72, 73)¶

1. GENERAL DESCRIPTION & PROPULSION MODULES (Page 164)¶

The ATR 42/72-600 series utilizes two Pratt & Whitney Canada PW127 series turboprop power plants. Each engine drives a Hamilton Sundstrand 568F six-bladed composite propeller assembly.

  PW127 TURBOPROP FREESTANDING CORE LAYOUT
  ┌────────────────────────────────────────────────────────┐
  │   [LPC MODULE] ──► [HPC MODULE] ──► [COMBUSTION CORE] │
  │        │                │                              │
  │   [LPT SPOOL ] ◄── [HPT SPOOL ] ◄── [ TURBINE EXHAUST] │
  │                                             │          │
  │   [REDUCTION GEARBOX (RGB)] ◄───────────────┘          │
  │        │                                               │
  │   [PROPELLER SHAFT (Np)]                               │
  └────────────────────────────────────────────────────────┘

1.1. Core Engine Structural Philosophies¶

Free Turbine Architecture: The gas generator section of the engine is aerodynamically coupled but mechanically separated from the power turbine assembly. This allows the high-pressure core spools to spin at optimal thermodynamic speeds independently of the propeller's rotational constraints.
Nominal Power Metrics: The PW127M engine core delivers a baseline performance output of 2475 shaft horsepower (shp) per side, flat-rated to remain efficient across diverse regional operating track segments.

2. AIRFLOW PATHS & GAS GENERATOR COMPRESSION LOOPS (Page 165)¶

Air entering the engine intake nacelle curves down through a debris-separation path before transitioning into the multi-stage axial and centrifugal compression systems.

2.1. Spool Velocity Terminology ($N_L$ and $N_H$)¶

The gas generator section utilizes two separate, nested concentric drive shafts to achieve progressive, high-efficiency pressure ratios before burning fuel inside the combustion throat:

Low-Pressure Spool ($N_L$): Comprises a single-stage axial compressor driven by a single-stage low-pressure turbine wheel.
High-Pressure Spool ($N_H$): Comprises a single-stage centrifugal compressor impeller driven by a high-pressure turbine wheel. This core governs the baseline engine idle and power generation tracking schedules.
Power Turbine Spool ($N_P$): A two-stage free turbine module located downstream in the exhaust flow path. It extracts the residual kinetic energy of the combustion gases to drive the front reduction gearbox (RGB), which steps engine rotational speed down to precise propeller RPM limits.

3. ELECTRONIC ENGINE CONTROL (EEC) SYSTEM MANAGEMENT (Page 166)¶

Each engine is managed by a dual-channel digital Electronic Engine Control (EEC) computer system. The EEC automatically schedules engine performance targets to reduce pilot workload and protect structural component limits.

3.1. Power Modulation Functions¶

Full-Authority Oversight: The active EEC channel processes real-time inputs from the cockpit Power Levers (PLA), ambient air parameters from the ADCs, and internal engine sensors to modulate fuel delivery precisely. It matches the required torque targets while actively guarding against core over-temperature ($ITT$) limits or engine surge stalls.
Automatic Rating Control: When the Power Levers are advanced into the forward detent slot (Notch), the EEC references the position of the cockpit Power Management Selector switch to schedule optimized outputs automatically for specific phases of flight: TO (Takeoff), MCT (Maximum Continuous), CLB (Climb), or CRZ (Cruise).

4. HYDRO-MECHANICAL UNIT (HMU) SYSTEM OPERATION (Page 167)¶

The Hydro-Mechanical Unit (HMU) serves as the main physical fuel control and metering component on each engine. It acts as the execution mechanism driven by the digital command outputs from the EEC.

4.1. EEC-to-HMU Interface Operations¶

Torque Motor Modulation: The active channel of the digital EEC steps an internal electrical torque motor inside the HMU. This motor moves metering valves to regulate high-pressure fuel flow into the combustion spray nozzles.
Manual Mode Reversion Fallback: If an electrical short circuit or computing exception drops both channels of an engine's EEC offline:
The active system trips offline, illuminating the amber ENG EEC FAULT Master Caution.
Control reverts instantly to Manual Mechanical Mode.
The internal torque motors freeze, and fuel scheduling defaults to manual mechanical linkages connected via tension cables directly to the cockpit Power Levers. Pilots must then manage the levers carefully to prevent manual exceedances of engine thermal parameters.

5. COCKPIT POWER LEVERS (PLA) QUADRANT SLOTS (Page 168)¶

The cockpit engine control quadrant houses twin Power Levers (PLA) on its left facing column. These levers allow pilots to manage thrust vectors directly across five primary physical stop zones.

  POWER LEVER POSITION SEGMENTS
  ┌────────────────────────────────────────────────────────┐
  │  [ MAX TO ]   ──► Maximum Forward Structural Thrust    │
  │       │                                                │
  │  [ NOTCH  ]   ──► Rating Management Zone (MCT/CLB/CRZ) │
  │       │                                                │
  │  [  FI  ]     ──► Flight Idle Stop (Aerodynamic Limit) │
  │ ═════════ ◄── MECHANICAL LATCH GATE LOCKS              │
  │  [  GI  ]     ──► Ground Idle Setting (Minimum Burn)   │
  │       │                                                │
  │  [  REV ]     ──► Reverse Blade Pitch Thrust Range     │
  └────────────────────────────────────────────────────────┘

5.1. Operational Quadrant Gate Rules¶

Flight Idle (FI) Gate Lock: A mechanical stop blocks the lever tracks at the Flight Idle boundary. This prevents pilots from accidentally dragging the power levers down into ground profiles during flight, which would collapse the wing lift lines due to sudden propeller drag braking.
Notch Selection Range: The primary operating zone for all standard flight phases. Placing the levers inside this detent delegates full thrust optimization scheduling to the active EEC computers.

6. COCKPIT CONDITION LEVERS (CLA) SYSTEM MODES (Page 169)¶

The right-hand facing tracking slot track on the center pedestal control group houses the twin Condition Levers (CLA). These levers are used to control engine fuel shutoff lines, manage propeller feather configurations, and set target speed governing loops.

  CONDITION LEVER REGULATORY GATES
  ┌────────────────────────────────────────────────────────┐
  │  [100% OVRD]  ──► Forces Max Prop Rotational Speed     │
  │       │                                                │
  │  [ AUTO ]     ──► Electronic Governing Range (82%-100%)│
  │       │                                                │
  │  [ FEATHER ]  ──► Mechanical Blade Edge Airflow Align  │
  │       │                                                │
  │  [ SHUT OFF]  ──► Drops Fuel Metering Logic to Absolute│
  └────────────────────────────────────────────────────────┘

6.1. Systemic Action Matrix¶

SHUT OFF Gate: Completely closes the main high-pressure fuel valve inside the HMU core, instantly killing the engine core spool.
FEATHER Gate: Directs high-pressure engine oil away from the propeller pitch change piston. This causes internal counterweights and feathering springs to twist the blades edge-on into the airflow, minimizing aerodynamic drag following a power loss event.
AUTO Mode Detent Selector: The standard operational selection for all normal flight regimes. This hands over propeller speed governance to electronic controllers, which maintain high-efficiency speed matrices automatically.

7. ENGINE FUEL MANAGEMENT & HEATER EXCHANGERS (Page 170)¶

Fuel arriving from the aircraft wing tanks passes through an integrated core treatment loop before entering the high-pressure compression combustion elements.

7.1. Fuel Processing Logistics Flow¶

Low-Pressure Inflow Entry: Fuel lines feed incoming fuel through a main engine-driven low-pressure mechanical pump module.
Fuel-to-Oil Heat Exchanger: The cold fuel stream cycles through a parallel-plate heat exchanger matrix. Hot engine lubricating oil runs along the opposite side of the plates. This layout transfers heat from the oil to warm the fuel, melting any micro-crystalline ice particles suspended in the fuel before they reach the main filters.
High-Pressure Filter Screening: Warmed fuel filters through a fine-mesh core element screen. If ice or contaminants clog the screen, a mechanical bypass valve pops open to maintain fuel flow to the engine. This generates a cautionary message on the flight deck panels.
HMU Delivery Stage: Treated fuel enters the internal pump chambers of the High-Pressure engine pump, which builds the extreme pressure lines required to atomize the fuel through the combustion spray rings.

Chapter Q. POWER PLANT (CONTINUED)¶

8. ENGINE OIL SYSTEM MECHANICAL ARCHITECTURE (Page 171)¶

The engine oil system provides continuous lubrication, cooling, and carbon seal clearing for the main engine bearings, while simultaneously delivering high-pressure hydraulic fluid to the reduction gearbox (RGB) and propeller control systems.

8.1. Lubrication Circulation and Scavenge Loop Flow¶

Oil Reservoir Supply: A self-contained oil tank is integrated directly into the intake housing compressor framework wrapper.
Pressure Delivery Stage: A main engine-driven pressure pump draws oil from the reservoir through a screen and pumps it past an internal pressure regulating relief valve to distribute clean fluid to the bearings, accessory drives, and the RGB torque-meter chambers.
Thermal Management Loop: High-temperature oil returning from the bearing cavities is drawn out by multiple independent scavenge pumps. The scavenge lines route the hot oil back through the fuel-to-oil heat exchanger and an air-to-oil cooling radiator assembly to lower core temperatures before returning the fluid to the main reservoir tank.
De-aeration and Venting: Centrifugal breathers remove entrained air and combustion blow-by gases from the oil stream, venting the separated gas overboard through the accessory gearbox exhaust port to stabilize case internal pressures.

8.2. Core Diagnostic Monitoring Limits¶

Real-time oil status metrics are processed by the FWS and rendered digitally onto the secondary EWD matrix columns when thresholds are breached:

Nominal Pressure Range: $55\text{ to }65\text{ psi}$ during standard flight configurations.
Low Pressure Caution (Amber): Drops below $40\text{ psi}$.
Low Pressure Warning (Red): Drops below $35\text{ psi}$, triggering the continuous repetitive chime (CRC). This requires immediate execution of the engine shutdown emergency checklist.
Maximum Oil Temperature Limit: $125^\circ\text{C}$ absolute structural safety boundary.

9. ENGINE IGNITION AND STARTING SYSTEM LAWS (Page 172)¶

The starting and ignition grid coordinates high-amperage electrical cranking loops with dual-element high-energy spark discharge paths to ensure stable fuel light-off during ground and in-flight restarts.

9.1. System Hardware Configurations¶

Starter-Generator Interface: The main 28V DC starter-generator behaves as a high-torque electric starter motor during the initial starting profile. Once engine core self-sustaining speeds are achieved, internal relays disconnect the starter circuits and switch the unit over to function as a standard 400A DC electrical generator.
Dual Ignition Exciters: Each engine features two independent high-voltage ignition exciters connected to separate spark igniter plugs located within the combustion chamber liner (Ignition A and Ignition B).

9.2. Automated Start Timeline Sequences¶

Ground Starting Law: Selecting a start mode initializes an automated sequence via the Electronic Engine Control (EEC). The starter motor engages to turn the high-pressure spool ($N_H$). At $10\%\ N_H$, the EEC arms the ignition exciters. Advancing the Condition Lever to START injects fuel. Once $N_H$ accelerates past $45\%$, the fuel light-off loop is stable, and the system automatically terminates the ignition current and cuts the starter circuit contactor.
In-Flight Windmilling Restart: Bypasses starter motor grid routing. Airflow milling through the unfeathered propeller blades turns the engine core components manually. Once the start selector is engaged, the ignition exciters provide a continuous spark arc until a self-sustaining combustion rise is completed.

10. PROPELLER CONTROL SYSTEM & ACTUATION HOUSINGS (Page 174)¶

The propeller system (ATA 61) utilizes a hydro-mechanical Propeller Control Unit (PCU) coordinated with a dual-channel digital Propeller Electronic Control (PEC) computer to precisely vary blade pitch angles. This maintains optimal aerodynamic efficiency while holding target rotational speed constants.

  PROPELLER MECHANICAL CONTROLLER ROUTING
  ┌────────────────────────────────────────────────────────┐
  │              PEC ELECTRONIC DESIGNATOR CORE            │
  └───────────────────────────┬────────────────────────────┘
                              │
                              ▼ [Torque Motor Current Adjusts]
  ┌────────────────────────────────────────────────────────┐
  │              PROPELLER CONTROL UNIT (PCU)              │
  │        (Modulates High-Pressure Oil Distribution)      │
  └───────────────────────────┬────────────────────────────┘
                              │
                              ▼ [Piston Linear Motion Tracking]
  ┌────────────────────────────────────────────────────────┐
  │             PITCH CHANGE BLADE ACCUATOR                │
  │     (Moves mechanical pitch pins to twist blades)      │
  └────────────────────────────────────────────────────────┘

11.1. Pitch Change Hub Mechanics¶

The hub assembly contains a central hydraulic actuator cylinder. Increasing oil pressure inside the forward piston cavity drives the blade tracking pitch pins toward a fine pitch (low angle/high RPM) configuration. Conversely, feathering springs, aerodynamic twisting moments, and mechanical counterweights use oil return lines to push the blade profiles back toward a coarse pitch or fully feathered profile (high angle/low drag).

11. PROPELLER SPEED GOVERNANCE AND MODES (Page 175)¶

Propeller operations follow rigid governor constraints to maintain target operational speeds ($N_P$) across distinct phases of flight, minimizing structural vibration and passenger cabin acoustics.

12.1. Variable Governor Targets Scheduling¶

When the cockpit Condition Levers (CLA) are set to the AUTO detent slot, the digital PEC automatically commands the PCU torque motors to vary blade pitch. This holds steady $N_P$ outputs to match selected profiles:

Takeoff and Departure Target: $100\%\ N_P$ ($1200\text{ RPM}$ at the propeller shaft) to maximize available thrust profiles.
Standard In-Flight Climb Target: $82\%\ N_P$ ($984\text{ RPM}$) to balance climb performance metrics with structural load limits.
Balanced Cruise Cruise Target: Scales smoothly down to a minimum noise baseline of $82\%\ N_P$, reducing engine wear and flight deck noise during extended cruise flight segments.

12.2. Mechanical Overspeed Protection Loops¶

To guard against fatal structural failures caused by a runaway propeller overspeed if the digital PEC line fails, the hub integrates two cascaded backup mechanical protection loops:

Primary Mechanical Governor: A flyweight governor inside the PCU assembly opens automatically if $N_P$ breaches $103\%$, bypass-metering oil to coarsen blade pitch and arrest the acceleration.
Overspeed Governor (OSG): An entirely independent backup governor valve that activates if $N_P$ reaches $109\%$. The OSG dumps oil out of the fine pitch piston cavity immediately, using the internal feathering springs to coarsen blade pitch rapidly and prevent catastrophic propeller hub disintegration.

12. PROPELLER BRAKE SYSTEM (HOTEL MODE - ENGINE 2) (Page 176)¶

Hotel Mode describes the operation of the Right Engine (Engine 2) running on the ground with its propeller mechanically locked at 0 RPM. This allows the engine core to turn and function as an Auxiliary Power Unit (APU), providing bleed air for cabin climate control and electrical power to the main DC/ACW buses without generating thrust hazards.

13.1. Hydraulic Locking Architecture & Engagement Boundaries¶

Locking is achieved via a high-torque mechanical disc brake caliper assembly mounted inside the Engine 2 reduction gearbox. The caliper is actuated by fluid pressure supplied by the primary BLUE Hydraulic System.

  HOTEL MODE ENGAGEMENT INTERLOCK SAFETY LOGIC
  ┌────────────────────────────────────────────────────────┐
  │             GROUND CONFIGURATION VERIFICATIONS         │
  │                                                        │
  │   - Aircraft Ground Transducers = WEIGHT ON WHEELS     │
  │   - Propeller Brake Control Switch = ENABLE / ON       │
  │   - Blue Hydraulic System Pressure = READY (3000 psi)   │
  │   - Engine 2 Condition Lever (CLA) = SHUT OFF GATE     │
  └───────────────────────────┬────────────────────────────┘
                              ▼
  ┌────────────────────────────────────────────────────────┐
  │            INTERLOCK SAFETY PROTECTION GATES           │
  │   (If all conditions are met, the brake caliper clamps) │
  └───────────────────────────┬────────────────────────────┘
                              ▼
  ┌────────────────────────────────────────────────────────┐
  │           ENGINE 2 START SEQUENCING PERMITTED          │
  │  ──► Core spins normally ($N_H$) ──► Propeller held at 0 RPM │
  └────────────────────────────────────────────────────────┘

System Restriction Warning: To prevent severe structural gear shear or structural fires inside the nacelle casing, the propeller brake can only be selected or released while the engine core is stationary or operating below the starter cutoff boundary. Engaging the brake loop while Engine 2 is running at stabilized idle configurations is blocked by hardwired interlock safety gates.

13. ENGINE / PROPELLER SYNOPTIC PAGE DISPLAY (SD PAGE) (Page 177)¶

Live performance metrics and structural vibration values are consolidated and rendered on the MFD SYS / ENG synoptic monitoring page to track powerplant parameters.

14.1. Synoptic Data Presentation Map¶

Torque Gauges ($TQ\%$): High-visibility round dial indicators overlaid with green limit sectors. Digital indexes turn amber if torque values exceed maximum rated structural limits for more than 20 seconds.
ITT Scale Meters: Track absolute Interstage Turbine Temperature values. The digital bars feature dynamic red start-limit tick marks ($950^\circ\text{C}$ ground start limit threshold) to help pilots track and catch a hot start before permanent blade damage occurs.
Vibration Index Sensors: Displays real-time vibration amplitude data for both the engine core spools ($N_H/N_L$) and the propeller hub bearings ($N_P$). Readings inside the white scale indicate normal operation; a steady rise into the amber warning sector indicates component imbalance or bearing degradation, requiring engineering inspection.

14. NON-NORMAL POWER PLANT FAULT CONDITIONS (Page 180)¶

Powerplant failures require immediate pilot recognition and structured coordination to safely manage aerodynamic tracking limits.

In-Flight Engine Flameout Identification¶

An engine core flameout caused by fuel starvation, structural component failure, or massive volcanic ash ingest tracks specific cockpit instrument indications:

Total torque output drops rapidly to zero ($0\%\ TQ$).
Interstage Turbine Temperature values drop significantly below standard combustion baselines ($ITT\text{ decay}$).
High-pressure core generator spool speeds drop below idle parameters ($N_H < 61\%$).
FWS Warning Output: The FWS triggers the Level 3 continuous repetitive chime (CRC), flashes the Red Master Warning light array, and displays the flashing red ENG 1(2) FLAMEOUT warning text on the central EWD.

Manual Feathering Override Protocols¶

If an engine failure occurs while the ATPCS is disarmed or if an internal hydraulic block prevents the auto-feather circuits from firing cleanly, the affected propeller may lock in an unfeathered windmilling state. This creates massive asymmetric drag that can compromise low-speed control authority.

Pilots must immediately override the automated systems and manually feather the propeller to stabilize the flight path:

Confirm and identify the failed engine using the EWD torque scales.
Retard the associated cockpit Power Lever to the Flight Idle (FI) stop gate.
Pull the associated cockpit Condition Lever (CLA) aft past the low-speed detents directly into the FEATHER slot. This mechanically opens the PCU dump valves, forcing the internal feathering springs and blade counterweights to twist the blades edge-on into the wind stream to eliminate the asymmetric drag profile.

Propeller Rotation and PEC Interfacing in Cold Temperatures (Page 181)¶

Operational safety profiles inside ground icing sectors require specific control laws to maintain line flexibility and protect composite propeller structures from tracking imbalances.

Ground Icing Operational Restrictions: When ambient temperatures fall below $0^\circ\text{C}$ in visible moisture conditions, centrifugal ice shedding profiles must be managed manually. Crews must periodically cycle the power levers to high-idle sectors to sling off asymmetrical clear ice coatings before structural vibrations initiate.
PEC Low Temperature Compensation: The Propeller Electronic Control (PEC) alters its blade pitch scheduling loops when processing extremely dense, low-temperature air data strings. It dampens structural actuator displacement speeds to prevent sudden oil pressure spikes inside the pitch-change cylinder housing.

15. POWERPLANT OPERATIONAL LIMITATIONS MATRIX (Page 182)¶

The Flight Warning System (FWS) uses predefined electronic gates to track compliance with maximum engine performance envelopes.

Operating Condition	Torque Limit ($TQ\%$)	Max ITT Target	Gas Gen speed ($N_H$)	Power Turbine ($N_L$)	Propeller Speed ($N_P$)	Time Limit
Takeoff (Nominal)	$100.0\%$	$765^\circ\text{C}$	$100.0\%$	$100.0\%$	$100\%$ ($1200\text{ RPM}$)	5 Minutes
Takeoff (ATPCS Uptrim)	$110.0\%$	$800^\circ\text{C}$	$101.5\%$	$101.2\%$	$100\%$ ($1200\text{ RPM}$)	10 Minutes
Max Continuous (MCT)	$100.0\%$	$800^\circ\text{C}$	$101.5\%$	$101.2\%$	$82\%\text{ to }100\%$	Continuous
Standard In-Flight Climb	$90.5\%$	$765^\circ\text{C}$	$98.2\%$	$97.5\%$	$82\%$ ($984\text{ RPM}$)	Continuous
Engine Ground Start	$0.0\%$	$950^\circ\text{C}$	—	—	—	Transient (Peak)
Maximum Transient	$120.0\%$	$840^\circ\text{C}$	$103.2\%$	$102.8\%$	$109\%$ ($1308\text{ RPM}$)	20 Seconds

16. ENG START PANEL (Page 185)¶

Source: direct reading of PNG page 187 (printed 185)

ATA 61/72

  ENG START PANEL
  ┌──────────────────────────────────────────────────┐
  │                                                  │
  │    START       ENG START         PROP BRAKE      │
  │   [A]  [B]    [MAYDAY] [MAYDAY]                  │
  │                                                  │
  │                   42/72 PEC                      │
  └──────────────────────────────────────────────────┘

CRANK: Dry motoring (no ignition).
START A OR B: On ground, only excite A or B is sufficient (except for the position A&B). In flight regardless of start selection (A, B or A+B) both exciters are energized.
ON: Starter engaged. At 45% NH, light goes off and the starter is disconnected.
FAULT: Illuminates when: engine ON with NH <61%, or >DCU failure during start, or starter failure, or ENG 1 only: ENG START selector on start position + PROP BRK ON + GUST lock not engaged.
ON (Ignition): Continuous ignition (both A & B). Memo panel light.
UNLOCK / PROP BRAKE: Not fully locked or not fully released. After 15 sec: FWS alarm. Also: 5 sec to unlock, 10 sec to lock.
PROP BRAKE: Brake fully locked — same indication on the memo panel.

17. ENG CONTROL PANEL (Page 185)¶

Source: direct reading of PNG page 187 (printed 185)

ATA 61/72

  ENG CONTROL PANEL
  ┌──────────────────────────────────────────────────┐
  │   ENG1          ATPCS           ENG2             │
  │   EEC1          [ARM]           EEC2             │
  │  [FAULT]        [OFF]          [FAULT]           │
  │  [ OFF ]                       [ OFF ]           │
  └──────────────────────────────────────────────────┘

ATPCS Arming & Trigger Conditions¶

ARMING CONDITIONS: - PWR MGT set on TO - ATPCS pb in - Both PL > 49° - Both TQ > 46% (72) and > 53% (42) - ARM green LT illuminated

ATPCS: - ARM on ground → uptrim + auto FTR D. 15° delay - ARM in flight (in case of go around) → FTR only

TRIGGER: One TQ below 18%. Cancel: PWR MGT off TO or ATPCS pb OFF or at least one PL retarded below 49° or both TQ >66%(72) and >53%(42).

EEC: Acts on stepper motor to regulate Fuel Flow. - FAULT flashing: EEC failure. The fuel flow is frozen to maintain the power. - FAULT steady: EEC failure. HMU base law → reversion. When FAULT flashing, do not deselect the EEC. Retard first the PL in the green sector (FAULT becomes steady; PL < 52°). - OFF: HMU base law → reversion.

18. PWR MGT PANEL (Page 186)¶

Source: direct reading of PNG page 188 (printed 186)

ATA 61/72

  PWR MGT PANEL
  ┌──────────────────────────────────────────────────┐
  │  [BOOST]       PWR MGT                           │
  │               ╭─────────╮                        │
  │  [FAULT1]     │ Rotary  │  [CLR]                 │
  │               │Selector │                        │
  │  PEC1  PEC2   ╰─────────╯                        │
  │  [FAULT1] [FAULT2]                               │
  │  [ OFF ]                                         │
  └──────────────────────────────────────────────────┘

BOOST (if installed): - ON: The boost can be selected on ground with the PL below FI, or in flight after an engine failure. When the torque is thermodynamically limited, the boost increases the torque: - With PWR MGT in TO by 4.5% up to 4000ft, 4% above 4000ft - With PWR MGT in MCT by 4% - The selection of the boost is latched when the PLs are advanced above FI, and cannot be changed during flight (except in case of engine failure). - FAULT: For any disagreement between the position of the push button and the rating of both EEC (MC+SC+FAULT+ENG BOOST on FWS).

PWR MGT: 2 on-side switches. E.H. bottom / R.H. TOP providing FDAU, PEC and EEC with basic power requirements.

OFF: TCS is deactivated and NP is limited at 102.5% if power is sufficient.

FAULT: Illuminates when both PEC are lost. FWS.

19. ATPCS TEST PANEL (Page 186)¶

Source: direct reading of PNG page 188 (printed 186)

ATA 61/72

ATPCS TEST selector (rotary knob) allows to check the correct functioning of the ATPCS. This rotary selector is spring loaded to neutral position.

20. IDLE GATE (Page 186)¶

Source: direct reading of PNG page 188 (printed 186)

ATA 61/72

IDLE GATE FAIL: Light illuminates amber and the FWS is activated when the gate does not engage automatically in flight or does not retract at landing.
IDLE GATE LEVER: Enables manual override in case of failure of the automatic logic or no DC power. In flight: push. On ground: pull. A red band appears.