A320neo CFM LEAP-1A Engine Start & Shutdown: Technician’s Reference

This technical reference details the ground start, shutdown, and abort procedures for the Airbus A320neo powered by CFM LEAP-1A engines. It outlines automatic and manual start sequences, FADEC operating parameters, and thermal stabilization limits for line mechanics and engineering students.

1. Core Safety Warnings & Ground Operational Cautions

1.1 Personnel Safety & Thermal Hazard Zones

• Thermal Accumulation Warning: Engine core components, external casings, and engine oil retain severe thermal energy for up to 1 hour following engine shutdown. Applicable high-temperature thermal gloves must be worn during all post-run inspections or maintenance interventions to prevent severe burns.
• Air Data Probe Hazards: Do not touch total air temperature (TAT), angle of attack (AOA), or pitot probes during or immediately following system operation. These probes reach extreme temperatures rapidly and will cause burns. Ensure all protective covers are removed prior to system power-up to avoid structural probe damage or cover combustion.
• Aerodynamic/Mechanical Hazards: Never attempt to arrest the rotation of the main fan blades by hand. Windmill forces can cause immediate severe personal injury or damage to the fan blade assemblies.
• Entry/Exit Corridor Restrictions: Engine operation must never exceed minimum ground idle speed if ground personnel are positioned inside the designated entry/exit safety corridor. Continuous positive communication between the flight deck and ground crew is mandatory, and inlet/exhaust hazard templates must be strictly observed by personnel in the entry/exit corridor.

1.2 Foreign Object Damage (FOD) & Environmental Wind Limits

• Area Cleanliness Protocol: All operating surfaces, including ramps, taxiways, and runways, must be verified completely clean and free of loose debris. The high-bypass suction of the engine presents a severe risk for foreign object ingestion, causing catastrophic core destruction or severe injury from high-velocity exhaust projectile discharge.
• Wind & Gust Vector Constraints: Before commencing any ground run, cross-reference environmental wind vectors against the applicable AMM wind limit restriction charts. Natural ambient winds and unpredictable, sudden gusts significantly distort and expand the engine’s safety danger envelopes.
• Cowling Structural Configuration: Never conduct engine run-ups above ground idle power with the thrust reverser cowlings open. If the engine is operated anywhere above idle, the fan cowlings must remain closed and fully latched to prevent severe airframe or cowling structural failure.

1.3 Airframe Structural Protection & Ground Safety Systems

• Uncommanded Forward Movement Mitigation: Verify that all landing gear ground safety locks are physically installed and primary wheel chocks are securely positioned.EMERGENCY ESCAPE MANEUVER: If during the engine ground-run test the aircraft starts to move forward, decrease the engine thrust immediately and stop the aircraft with the parking brake.
• Fuselage Door & Support Equipment Clearances:
  • Passenger Doors: All main cabin passenger doors must be fully closed, and all passenger loading stairs/jetways completely removed, if any single engine is operated above ground idle power.
  • Cargo Compartment Doors: All cargo hold doors must be fully locked, and associated ground loading machinery cleared, if Engine 2 is operated at idle or above, or if any engine is operated above idle power.
• Fuselage Over-Pressurization Hazard: Prior to operating powerplants above idle power settings, ensure the cabin pre-pressurization or residual pressure risk is eliminated after subsequent engine shutdown. To do this, ensure the air conditioning outflow valve is open during all the test to prevent injury.
• Flight Control Surface Interference: Ensure the full structural travel sweeps of all primary and secondary flight control surfaces are entirely clear of ground obstructions or personnel before starting to prevent structural binding, equipment damage, or crushing injuries.
• Hydraulic Cross-Contamination & Pump Damage: Ensure that no hydraulic ground power units are connected to the aircraft’s hydraulic manifolds during engine start or run operations. Simultaneous connection creates localized hydraulic spikes capable of destroying the engine-driven hydraulic pumps.
• Fuel Pump Dry Run Prevention: Never operate the engine unless positive fuel inlet pressure is actively supplied to the engine-driven fuel pump assembly. The fuel is necessary to lubricate the engine fuel pump and prevent damage.

2. Pre-Start Job Set-Up & System Configurations

2.1 Workspace Setup, External Inspections, and Circuit Breakers

1. Chock Deployment: Secure standard wheel chocks in front of each forward outboard Main Landing Gear (MLG) wheel. If high-power testing operations (above ground idle) are planned post-start, place specialized engine run-up chocks in front of each forward MLG wheel assembly and shift the chock levers up into the locked position.
2. Structural Zoning: Ensure the aircraft is stopped in a clear area specified for engine ground runs that agrees with the engine danger areas given in the engine safety precautions (Zone 210 and Zone 400 per AMM Chapter 71).
3. Inlet and Exhaust Verification: Remove all protective inlet plugs and exhaust covers. Inspect internal ducts to ensure they are clear of unwanted objects.
4. Cold Weather Cold-Section Verification: Conduct a visual check of the temperature sensors, fan inlet, and exhaust areas. If snow or ice has collected in the fan duct, manually confirm that the fan turns freely. Ensure that the engine inlet, inlet lip, fan, spinner, and fan exhaust duct are clear of ice or snow. If the fan does not turn freely, melt the ice or snow with hot air before an engine operation. For extreme cold, execute specialized fan blade de-icing protocols per AMM Chapter 12.
5. Fluid Discharge Assessment: Check the drain ports for fuel, oil, and hydraulic leaks per AMM Chapter 71. Ensure that any fuel drained from the engine does not cause a fire hazard.
   • Extreme Sub-Zero Exception: In case of extreme cold weather conditions where Outside Air Temperature (OAT) drops below -20°C (-4°F), localized fuel leaks from the drain may occur and should not be considered abnormal. A check for fuel leaks at the drain mast shall be performed only after the engine is fully stabilized at idle.
6. Air Data Probe Uncovering: Remove covers from total air temperature, angle of attack, and pitot probes to prevent probe and cover damage or burning.
7. Aerodynamic Control Layout: Verify that the flaps and slats are retracted per AMM Chapter 27.
8. Electrical Grid Configuration: Energize the aircraft electrical circuits from external power or the APU per AMM Chapter 24.
9. Circuit Breaker Verification: Check and verify that all required Engine Ignition, EIU, and FADEC circuit breakers on panels 49VU and 121VU are closed as per the AMM line-up.

2.2 Internal Cockpit Panel & System Initializations

1. EIS Start Procedure: Complete the EIS start procedure per AMM Chapter 31. Clear all active engine maintenance alerts or warnings before starting.
2. Fire System Check: Perform the operational test of the engine fire and overheat detection loop/squib activation systems per AMM Chapter 26. Obey your local fire-fighting regulations.
3. Hydraulic Priming and Fluid Review: Get the HYDRAULIC page on the lower ECAM display unit. Confirm that the pressure of the Green reservoir (for Engine 1) or the Yellow reservoir (for Engine 2) is correct, and verify the reservoir fluid level is correct to provide lubrication to the engine-operated pumps.
4. Hydraulic Pump Lineup: On the overhead HYD/FUEL panel 40VU, confirm that the OFF legend of the ENG 1(2) PUMP pushbutton switch is off.
5. Braking and Thrust Configuration:
   • Set the PARKING BRK control switch on panel 110VU to ON.
   • Confirm the brake pressure indication on the brake yellow-pressure triple-indicator on central instrument panel 400VU is correct. If necessary, pressurize the brake accumulator with the yellow pump per AMM Chapter 29.
   • On the central pedestal ENG panel 115VU, confirm the ENG/MASTER 1(2) control switch is in the OFF position.
   • Verify both throttle control levers are firmly locked in the idle stop position (zero on the graduated sector).
   • Verify the landing-gear normal control lever is in the DOWN position.
6. Fuel Delivery Alignment: Get the “FUEL” page on the lower ECAM display unit. Make sure there is a minimum quantity of fuel in the fuel tanks to perform the associated test. On panel 40VU, if there is fuel in the center tank, make sure the MODE SEL is in AUTO (the MAN legend off). Push all the FUEL/PUMPS pushbutton switches inward (the OFF legends go off).
7. Pneumatic Manifold Charge: Supply the aircraft pneumatic system from the APU bleed or through the HP ground connector per AMM Chapter 36.
8. Anti-Collision Notification: Set the EXT LT/BEACON switch on overhead panel 25VU to the ON position.

2.3 Special Ground Icing Shedding Operations & Fleet Adaptations

• Ground Icing Shedding Protocol: In case of ground operation in icing conditions (Outside Air Temperature (OAT) 3°C / 37°F or less) or in case of increased fan vibration (with or without the ENG X HIGH VIBRATION message started) due to fan ice accumulation, execute the shedding procedure every 60 minutes:
  1. Increase the speed smoothly to at least 45% N1.
  2. Maintain that thrust level for 5 seconds minimum.
  3. Decrease the thrust to idle. Repeat as necessary to reduce fan vibration at intervals of no more than 60 minutes.
  • Vibration Characteristics Note: The engine vibration can indicate more than the normal operating range up to the maximum display value during the ice shedding, but this will have no adverse effect on the engine.
  • Ground Run Time Limit: If takeoff is not accomplished within 120 minutes of operation in ground icing conditions, shut down and perform the inspection per AMM Chapter 71.
• A321 XLR Flight Control Protection: To avoid the unintended generation of the F/CTL ALTERNATE LAW ECAM caution during ground engine runs on the A321 XLR, access the MCDU INIT PAGE and manually insert valid values for Zero Fuel Weight (ZFW) and Zero Fuel Weight Center of Gravity (ZFWCG).

3. Normal Automatic Start Procedure

3.1 Step-by-Step Cockpit Execution

1. On the ENG panel 115VU, rotate the ENG/MODE selector switch to IGN/START.
   • System Response: The lower ECAM display unit automatically brings the ENGINE page into view. Ensure engine alerts and warnings are cleared prior to starting.
2. Manifold Check: Confirm that the recommended minimum starter air pressure with the start valve open after initiating the start is 25 psi (1.7237 bar). Confirm total engine oil quantity is correct.
   • Starter Air Pressure Caution: Monitor the start cycle very carefully when the starter air inlet pressure is lower than recommended (special operation conditions). This can cause longer times to go to idle and higher EGT peaks.
   • Dynamic Fluid Note: The oil level in the oil tank can go down by 7.0 liters (1.8492 US gallons) during start as internal system cavities prime.
3. On panel 115VU, set the respective ENG/MASTER 1(2) control switch to the upward ON position.
4. Scanning and Monitoring Protocol:
   • Upper ECAM: Continuously monitor the important parameters: N1, N2, EGT, and Fuel Flow (FF).
   • Lower ECAM: Monitor Oil Pressure and valve symbology on the ENGINE page.

3.2 FADEC System Logic & Parameter Sequences

• FADEC Autonomy: In the automatic mode, the Electronic Engine Control (EEC) provides automatic sequencing of the starter, ignition, and fuel supply.
• Automatic Dry Cranking: Depending on the engine thermal state, the FADEC can command an automatic dry cranking phase before the start of the engine. The dry cranking may last up to approximately 1 minute, during which the FADEC logic limits the maximum N2 to 30%. During the dry cranking, the vibration level increases but remains below the amber display limit in normal operating conditions. The EEC will authorize ignition only when the automatic dry cranking is completed. After completion of pre-start motoring, the normal ground autostart procedure will proceed.
• Manifold Prefill Function: During motoring (after the master switch has been turned ON), there is a manifold prefill function that will open the Fuel Metering Valve (FMV) to pre-fill the fuel manifold. This commonly lasts less than 10 seconds, but is allowed to take up to 30 seconds. Light-off will not be attempted during pre-fill. Cold temperature conditions may extend time to light-off.
• Automated Failure Strategy: In the automatic mode, the EEC will close the fuel metering valve if light-off is not attained within 15 seconds. The engine will then automatically dry motor for 30 seconds, and then perform two additional start attempts before flagging a fault.
• Automated Step Indications Matrix:
  1. ENG MASTER Switch ON: The symbol for the starter valve opens on the ECAM ENGINE page.
  2. N2 Climbs Above 20%: When the pre-start automatic dry cranking is completed, the A or B indication comes into view below the IGN text block.
  3. Light-Off: Typically occurs within 2 to 3 seconds after the fuel metering valve opens (indicated by immediate EGT rise).
  4. At 55% N2: The ignition system de-energizes (IGN OFF appears).
  5. At 63% N2: The symbol for the starter valve automatically returns to the closed position.
• Pneumatic Pack Isolation: When the pack valves start to close, the FAULT legend of the AIR/COND PACK 1/2 pushbutton switches on the overhead AIR COND panel 30VU come on until the pack valves are fully closed.

3.3 Post-Start Idle Optimization

• Stabilized Idle Verification: The engine operates at a stabilized ground idle only when there is a positive oil pressure indication. Positive oil pressure must be indicated by the time the engine reaches idle speed. A stabilized pressure below a minimum of 17 psi (1 bar) requires an immediate engine shutdown.
• Viscosity Surges: During cold weather operations, oil pressure peaks to full scale may occur due to high oil viscosity. Pressure should decrease as oil temperature increases. In all cases, if the oil pressure remains above the normal range after the oil temperature has stabilized within limits, the engine should be shut down and the cause investigated.
• Thermal Conditioning (Warm-up): Once engine idle speed stabilizes, return the ENG/MODE selector switch to NORM. It is recommended that the engine operates at or near idle for a minimum of 3 minutes before you increase it to high power. You must move the throttle control lever slowly, carefully, and smoothly when possible. Taxi time at or near idle can be used as part of the 3-minute warm-up time.
• Troubleshooting Option: If an automatic start problem occurs, set the ENG/MODE switch to NORM and the ENG/MASTER 1(2) switch to OFF. After the starter is cool, the operator must make a decision: try another auto or manual start, or stop and correct the problem.

4. FADEC Automatic Start Abort Protocol

If an automatic start sequence is aborted by the system due to a parameter fault:

1. On the pedestal ENG panel 115VU, rotate the ENG/MODE selector switch to NORM and return the affected ENG/MASTER 1(2) switch down to OFF.
2. Ensure the starter assembly has cooled completely before attempting a subsequent start cycle.

CRITICAL SAFETY WARNING: AUTO-CRANK PURGE

After an abort of the engine starting sequence, a dry crank to remove fuel vapors will occur, accompanied by the ECAM message AUTO CRANK IN PROGRESS.

On completion of the dry crank, ALWAYS put the ENG/MASTER switch back to the OFF position when instructed by the ECAM message ENG MASTER OFF.

If you only change the position of the engine mode selector switch from IGN/START to NORM without physically turning the ENG/MASTER switch to OFF, the FADEC system will not complete the abort sequence. This leaves the starting system active, creating an immediate risk that the engine will execute an uncommanded start. This can cause severe injuries to persons and damage to equipment.

5. Normal Manual Start Procedure

5.1 Starter Motor Duty Cycles & Speed Operational Envelope

• Engagement Speed Ceiling: Never engage the starter motor assembly if the core engine rotational speed (N2) is tracking above 63%.
• Starter Duty-Cycle Limits: Maintenance crews must strictly pace manual starts or continuous motoring runs using the following timing matrix:
  • Standard Consecutive Cycle: Up to three (3) consecutive cycles are permitted. Each cycle has a maximum duration of 2 minutes, with a mandatory 60-second rest period at the end of each cycle.
  • Three-Cycle Limit: After completing these three consecutive cycles, wait for 15 minutes to let the starter become cool before you try a new start or motoring run.
  • Extended Maintenance Cycle: A single continuous 5-minute cycle is permitted, followed by a mandatory 5-minute cooling period. This extended timing option is strictly applicable for periodic maintenance activities.

5.2 Step-by-Step Manual Sequence Execution

1. On the central pedestal ENG panel 115VU, rotate the ENG/MODE selector switch to IGN/START.
   • System Response: The lower ECAM display unit automatically brings the ENGINE page into view. Before you start, it is recommended to erase all the engine alerts and warnings.
2. Pressure Pre-Check: Confirm that the recommended minimum starter air pressure with the start valve open after initiating the start is 25 psi (1.7237 bar), and ensure oil quantity is correct.
   • Dynamic Fluid Note: The engine oil level can drop by up to 7.0 liters (1.85 US gallons) during this rotation cycle.
3. On the overhead panel 22VU, push the respective ENG/MAN/START/1(2) pushbutton switch inward.
   • System Response: The ON legend of this pushbutton switch comes on. On the lower ECAM display unit ENGINE page, the symbol for the starter valve moves to the open position.
4. Initial Rotation Verification: Verify prompt core N2 acceleration and confirm positive oil pressure registration on the lower ECAM ENGINE page.
   • Pneumatic Supply Advisory: If you use a starter air pressure that is less than the recommended level, a slow N2 acceleration and a subsequent RPM hang-up can occur.

5.3 Manual Light-Off Monitoring & Troubleshooting Parameters

1. When N2 gets the maximum motoring speed (which must be a minimum of 20% N2) AND exactly 1 minute has elapsed since the overhead ENG/MAN/START/1(2) pushbutton switch was pushed:
   • On the central pedestal ENG panel 115VU, set the respective ENG/MASTER 1(2) control switch to the ON position.
2. ECAM Integration Tracking:
   • Upper ECAM: Closely monitor main parameters: N1, N2, EGT, and Fuel Flow (FF). The stall and low fan speed indications will be shown on the upper ECAM display unit. Because the automatic start sequence is completely bypassed, the operator must be prepared to abort the start when the parameters are near or above the limits.
   • Lower ECAM: Confirm that the AB indication comes into view directly under the IGN text block on the ENGINE page, indicating both ignition channels are active.
3. Light-Off Window: The engine light-off will usually occur 2 to 3 seconds after you set the ENG MASTER control switch to the ON position. If the light-off does not occur within 15 seconds, you must manually abort the start per the Manual Start Abort Procedure outlined below.
4. Immediate Manual Abort Criteria: The operator must immediately abort the manual start sequence if the Exhaust Gas Temperature (EGT) quickly increases and a slow N2 acceleration occurs.
   • System Malfunction Diagnosis: These can be the symptoms of incorrect fuel scheduling, faulty instrumentation, engine damage, low starter air pressure, or too much engine damage. Monitor the upper ECAM display unit for possible messages.
5. Thermal Targets: The temperatures of a usual start are less than 500°C (932°F). You can continue a start with a slow N2 acceleration from the light-off to idle and a low EGT indication (unsatisfactory fuel schedule). You must abort and correct the start if the temperatures exceed 725°C (1337°F).
6. Starter Disengagement: At a minimum of 63% N2, confirm that the symbol for the starter valve automatically moves to the closed position and that the ECAM AB indication goes out of view.
7. On the overhead panel 22VU, release the ENG/MAN/START/1(2) pushbutton switch. Confirm that the internal ON legend goes off.
8. Idle Stabilization: Verify positive oil pressure (minimum 17 psi / 1 bar). Move the ENG/MODE selector switch to NORM. It is recommended that the engine operates at or near idle for a minimum of 3 minutes warm-up before you increase it to high power.

6. Start Sequence: Normal vs. Manual

7. Engine Shutdown Procedure

7.1 Thermal Stabilization Run Times

Before taking an engine offline, it must undergo precise thermal stabilization to equalize internal gradients and avoid undercowl thermal heat soak-back:

• Standard Operation: Before you stop the engine, operate it at or near idle for 3 minutes immediately prior to the shutdown to thermally stabilize the engine hot section. Normal ground taxi tracking can be counted directly toward this 3-minute cool-down block.
• High-Thrust Static Operations: Following high-thrust static ground operation, such as a maximum power assurance check or vibration survey, operate at idle thrust for a period of no less than 10 minutes to thermally stabilize the engine and reduce undercowl soak-back temperatures prior to shutdown.
• Emergency Operational Exemption: The above thermal stabilization times do not apply in those cases where an approved abnormal or emergency procedure specifies an immediate engine shutdown.

7.2 Shutdown Sequence Execution & Post-Shutdown Systems Monitoring

1. Verify the primary throttle control lever is set against the idle stop position.
2. On the pedestal ENG panel 115VU, guide the targeted ENG/MASTER 1(2) switch down to OFF.
   • System Safety Alignment: Make sure that the ENG/MASTER 1(2) control switch is fully engaged in the OFF detent after shutdown.
3. Decay Profiling: Monitor the EGT, N2, and fuel flow during the shutdown to confirm the fuel shutoff. Make sure that the EGT and N2 RPM decrease when the fuel is shut off to absolute zero.
4. Post-Shutdown Tailpipe Fire Management: > CAUTION (EMERGENCY TAILPIPE FIRE PROCEDURE): Be prepared to dry motor the engine with the starter if there is a post-shutdown fire indication. Engine damage can be caused. If a steady decrease in the EGT does not occur after the shutdown, execute a dry motoring run immediately using starter air pressure until the tailpipe fire is completely extinguished.
   • Soak-back Behavior: After the engine shutdown is completed, and the rotation is fully stopped, the EGT will normally slowly increase. This is caused by a normal temperature soak-back and must not be misinterpreted as an active internal fire.
5. Residual Fluid Pressures: After the engine shutdown is completed, the oil pressure indicator can show a residual pressure. The allowable residual oil pressure limit is +/- 7 psi (+/- 48 kPa).
6. Systems Isolation:
   • On the overhead HYD/FUEL panel 40VU, release all the FUEL/PUMPS pushbutton switches (confirming all internal OFF legends come on).
   • Set the EXT LT/BEACON switch on overhead panel 25VU to OFF.
7. Probe Management: If required, reinstall all protective covers onto the TAT, AOA, and pitot probes. Do not install the probe covers immediately after the engine shutdown; allow sufficient cooling time to prevent melting the covers or damaging the air data sensors.
8. Electrical Grid Power Down: De-energize all primary aircraft electrical power systems per AMM Chapter 24 if testing operations are complete. Stop the pneumatic supply to the aircraft by disconnecting the HP ground power unit or stopping the APU per AMM Chapters 36 and 49. Complete the EIS stop procedure per AMM Chapter 31.

8. Manual Start Abort & Clearing Procedure

This procedure must be executed immediately when it is necessary to stop an engine start in the manual mode in case of an ECAM indication requiring an engine shutdown.

1. On the pedestal ENG panel 115VU, set the affected ENG/MASTER 1(2) control switch to OFF. Ensure that the switch lever is fully engaged in the OFF detent after shutdown.
2. Fuel Cutoff Audit: Monitor the EGT, N2, and fuel flow during the shutdown to confirm the fuel shutoff.
   • CAUTION: BE PREPARED TO DRY MOTOR THE ENGINE IF THE EGT DOES NOT DECREASE. DRY MOTORING THE ENGINE CAN PREVENT A FIRE AFTER SHUTDOWN.
   • Make sure that the EGT and N2 RPM decrease when the fuel is shut off. If a steady decrease in the EGT does not occur after the shutdown, do a dry motoring until the fire is extinguished. (Remember that EGT will normally slowly increase post-stoppage due to temperature soak-back).
3. On the overhead panel 22VU, release the ENG/MAN START 1(2) pushbutton switch (confirming the internal ON legend goes off).
4. On the pedestal ENG panel 115VU, put the ENG/MODE/CRANK/NORM/START selector switch to NORM or CRANK if some fuel has been injected to safely execute a dry motoring run and clear residual fuel vapors from the combustion chamber.
5. Secure Alignment: On the overhead HYD/FUEL panel 40VU, release all the FUEL/PUMPS pushbutton switches (confirming all internal OFF legends come on). Set the EXT LT/BEACON switch on overhead panel 25VU to OFF. Let the air data probes cool down completely, reinstall the probe covers, and de-energize all aircraft electrical power systems per AMM Chapter 24. Disconnect any ground pneumatic supply or shut down the APU per the relevant AMM chapters.

⚠️ Educational Use Only: This guide is for educational and quick-reference purposes only and does not replace the official Aircraft Maintenance Manual (AMM). Maintenance personnel must verify all procedures against active AMM data specific to the aircraft tail registration and fleet configuration prior to live operations.