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Power Plant Abnormals

Gulfstream G450 Abnormals

While the G450 shares the GV type, it is really a mix of the GIV and G550. The core of the engine comes from the GIV and most of the accessories and outer shell are from the G550. You really need to think of these engines are an entirely new powerplant and that will make troubleshooting easier.


 

Airstart - Windmilling

Airstarts in the G450 are actually easier than they were in the GV/G550 and even further back. The problem is the nomenclature can be confusing and the manuals are wrong in places.

First off, it is called "Airstart Windmilling" because in the GV we had several types of airstarts and you had to have a name for each. In the G450 we have one and only one option: Airstart - Windmilling.

Secondly, the start envelope begins at 250 KCAS and ends at 25,000 feet. You should not attempt a start until you've descended to 25,000 feet and make sure you have at least 250 KCAS. Will the engines start outside this envelope? Probably, but the "guaranteed start" envelope is as shown below.

Finally, despite the lack of a starter-assisted air start procedure, the starter motors will work in flight. There are two procedures in the book to have you crank the starters to provide hydraulic pressure: Right Engine Failure and Complete Left/Aux Hydraulic Failure and Left Engine Failure and Right Hydraulic Failure. But if things are not going well and the windmilling start isn't working, you do have another option.

Oh yes, one more thing. The procedure tells you to perform steps 11 through 17 if you get stable engine idle and skip to step 18 if you don't. I think step 18 is intended for a good start so you should perform 11 through 18 for a good start and skip to 19 for a failed start.

Start Envelope

images

Figure: Airstart Envelope, from G450 Aircraft Operating Manual §01-80-10, Figure 1.

Procedure

[G450 Airplane Flight Manual §4-08-20]

    CAUTION: ALWAYS ENSURE THAT THE POWER LEVER IS AT IDLE DURING STARTING. THE FLIGHT CREW IS RESPONSIBLE FOR MONITORING LP, HP AND TGT DURING AIRSTARTS. THE FADEC SYSTEM WILL NOT AUTO-ABORT AN AIRSTART FOR A TGT EXCEEDANCE.

    WARNING: VERIFY PROPER ENGINE: LEFT OR RIGHT.

  1. Inoperative Engine Power Lever . . . IDLE
  2. Affected Engine Fuel Control . . . OFF
  3. Affected Engine Bleed / ECS PACK . . . OFF
  4. Affected Generator . . . OFF
  5. L / R Main and Alternate Boost Pumps . . . ON
  6. Altitude / Airspeed . . . ESTABLISH 25,000 FT OR BELOW / 250 KCAS MIN
  7. NOTE: If the engine has been cold-soaked, select backup engine instruments (STBY ENGINE page) on MCDU 1. The TGT response on the STBY ENGINE page will be the first indication of engine start.

  8. Affected Engine HP RPM . . . INDICATING
  9. NOTE: The FADEC will not allow fuel to the engine below 9% HP RPM.

  10. Autothrottles . . . OFF
  11. Affected Engine CONT IGN . . . ON
  12. Affected Engine FUEL CONTROL . . . RUN
  13. CAUTION: THE FLIGHT CREW IS RESPONSIBLE FOR MONITORING LP, HP AND TGT DURING AIRSTARTS. THE FADEC SYSTEM WILL NOT AUTO-ABORT AN AIRSTART FOR A TGT EXCEEDANCE.

    NOTE: When attempting a windmill airstart of a cold-soaked engine, indication of engine start may take up to thirty (30) seconds. Stable engine idle conditions may not be achieved for up to ninety (90) seconds.

  14. Affected Engine FF (Fuel Flow) / TGT / RPM . . . MONITOR
  15. NOTE: Fuel flow will not indicate above zero until 9% HP RPM. Monitor TGT rise to determine indication of successful start sequence. If stable engine idle is achieved, perform steps 11 thru 17. If engine fails to restart or accelerate to idle, proceed to step 18.

  16. Affected Engine Oil Pressure / Oil Temperature . . . CHECK
  17. CAUTION: WHEN USING CONTINUOUS IGNITION, TO AVOID INADVERTENT ENGINE SHUTDOWN, IDENTIFY THE CONTINUOUS IGNITION SWITCH PRIOR TO SELECTION OF THE L-R CONT IGN SWITCH TO OFF.

  18. Affected Engine Continuous Ignition . . . OFF
  19. ISOLATION VALVE . . . CLOSED
  20. Affected Engine Bleed / ECS PACK / Generator . . . REINSTATE
  21. Stabilized Engine . . . ALLOW ENGINE TO IDLE 1 MINUTE THEN ACCELERATE SLOWLY TO DESIRED POWER SETTING
  22. Fuel Balance . . . MONITOR / MAINTAIN
  23. If the engine fails to restart or accelerate to idle:

  24. TCAS . . . TA / RA
  25. If the engine fails to restart or accelerate to idle:

    NOTE: The flight crew shall agree on the correct (affected) FUEL CONTROL switch prior to placing it in the OFF position.

  26. Affected Engine FUEL CONTROL . . . OFF
  27. CAUTION: WHEN USING CONTINUOUS IGNITION, TO AVOID INADVERTENT ENGINE SHUTDOWN, IDENTIFY THE CONTINUOUS IGNITION SWITCH PRIOR TO SELECTION OF THE L-R CONT IGN SWITCH TO OFF.

  28. Affected Engine Continuous Ignition . . . OFF
  29. Before attempting another start, allow the engine to drain for at least 30 seconds.

  30. Procedure . . . RE-ATTEMPT AT LOWER ALTITUDE AND HIGHER AIRSPEED

Alternate Start

This procedure exists for one thing and one thing only: if the START MASTER switch is broken. You replace it with the CRANK MASTER, you need to use continuous ignition, and you have to be vigilant because the FADEC is on holiday.

Procedure

[G450 Airplane Flight Manual §2-08-10]

    CAUTION: DURING AN ALTERNATE START, IT IS THE RESPONSIBILITY OF THE CREW TO MONITOR ENGINE PARAMETERS FOR START ANOMALIES AND LIMITATIONS EXCEEDANCES. IN THE EVENT OF A STARTING ANOMALY OR LIMITATION EXCEEDANCE, THE START MUST BE MANUALLY ABORTED.

  1. BCN . . . ON
  2. Parking Brake . . . SET
  3. Power Levers . . . IDLE
  4. GUST LOCK . . . OFF
  5. L / R MAIN Boost Pumps . . . ON
  6. ENGINE CONTROL . . . EPR MODE
  7. ENGINE START Page . . . SELECTED
  8. NOTE: Check that residual TGT is less than 200°C. If not, perform engine crank cycle to reduce residual TGT.

    CAUTION: FOR STARTS WITH TAILWIND COMPONENTS GREATER THAN 10 KTS, ALLOW ENGINE TO ACHIEVE MAX CRANKING RPM AND VERIFY THAT POSITIVE LP RPM IS ACHIEVED PRIOR TO SELECTING FUEL CONTROL TO RUN.

  9. BLEED AIR Pressure . . . CHECK 32 PSI MINIMUM
  10. CRANK MASTER . . . ON
  11. CAUTION: IF THE POWER LEVER IS NOT AT IDLE, AN AMBER LR Throttle Configuration CAS MESSAGE WILL BE DISPLAYED. THE START WILL CONTINUE AND THE ENGINE WILL ACCELERATE TO THE THRUST SELECTED BY THE POWER LEVER. THIS IS NOT RECOMMENDED. ALWAYS ENSURE THAT POWER LEVERS ARE AT IDLE DURING STARTING.

    CAUTION: CONTINUED USE OF THE STARTER IS LIMITED TO THREE (3) CRANK CYCLES, WITH A MAXIMUM OF THREE (3) MINUTES PER CYCLE. DELAY FIFTEEN (15) SECONDS BETWEEN START CYCLES. AFTER THREE (3) START CYCLES DELAY USE OF THE STARTER FOR AT LEAST FIFTEEN (15) MINUTES.

  12. R CONT IGN . . . ON
  13. IGN . . . DISPLAYED
  14. NOTE: The IGN icon will appear on the engine instruments display with CONT IGN ON.

  15. R ENG START . . . PRESS
    1. SVO . . . DISPLAYED
    2. NOTE: SVO icon will appear on the engine instruments display during start.

    3. Positive LP RPM . . . CHECK
    4. EVM . . . CHECK
    5. NOTE: The EVM system is designed to monitor engine vibrations at idle and above. Random, spurious EVM values, sometimes above the alert level (0.60), may be observed during the start sequence. This condition is normal.

    6. R FUEL CONTROL . . . RUN AT 20% HP RPM OR MAX CRANK RPM, WHICHEVER IS FIRST
    7. Fuel Flow / TGT . . . MONITOR
    8. SVO . . . OUT AT APPROXIMATELY 44% HP RPM
    9. Idle HP RPM . . . CHECK 49% HP RPM MINIMUM
  16. R CONT IGN . . . OFF
  17. IGN . . . OUT
  18. R Oil Pressure . . . CHECK 17 PSI
  19. NOTE: For starts with warm oil, the amber Oil Pressure Low CAS message may illuminate momentarily during the start.

  20. R SYS Pressure . . . CHECK 3000 (±300) PSI
  21. PTU . . . ARM
  22. PTU Pressure . . . CHECK 3000 (+300 / -400) PSI (varies with load)
  23. Single Rudder CAS Message . . . DISPLAYED
  24. L CONT IGN . . . ON
  25. IGN . . . DISPLAYED
  26. NOTE: The IGN icon will appear on the engine instruments display with CONT IGN ON.

  27. L ENG START . . . PRESS
    1. SVO . . . DISPLAYED
    2. NOTE: SVO icon will appear on the engine instruments display during start.

    3. Positive LP RPM . . . CHECK
    4. EVM . . . CHECK
    5. NOTE: The EVM system is designed to monitor engine vibrations at idle and above. Random, spurious EVM values, sometimes above the alert level (0.60), may be observed during the start sequence. This condition is normal.

    6. L FUEL CONTROL . . . RUN AT 20% HP RPM OR MAX CRANK RPM, WHICHEVER IS FIRST
    7. Fuel Flow / TGT . . . MONITOR
    8. SVO . . . OUT AT APPROXIMATELY 44% HP RPM
    9. Idle HP RPM . . . CHECK 49% HP RPM MINIMUM
  28. L CONT IGN . . . OFF
  29. IGN . . . OUT
  30. L Oil Pressure . . . CHECK 17 PSI
  31. NOTE: For starts with warm oil, the amber Oil Pressure Low CAS message may illuminate momentarily during the start.

  32. CRANK MASTER . . . OFF
  33. L SYS / R SYS / PTU Pressure . . . CHECK 3000 / 3000 / 0 PSI
  34. Single Rudder CAS Message . . . NOT DISPLAYED

Chips Are Down Start

The book gives you several options from altitude to your inevitable landing with or without the engines turning. But what if you run out of altitude and airspeed for the book's only option of a windmilling start? Can you use the starter? Sure, the plumbing is there. Don't believe it?

Look up the procedure for Right Engine Failure and Complete Left/Auxiliary Hydraulic Failure as well as Left Engine Failure and Right Hydraulic Failure. Both these procedures allow the engine starter to be used to generate hydraulic pressure.

Did I say procedure? There is no procedure. But if the chips are down, this knowledge can be useful.

Cold Weather Start

If the aircraft has been cold soaked lower than -20°C, the APU batteries should be warmed by external means. For temperatures colder than -15°C, the cockpit overhead panel should be warmed to ensure the APU displays are readable. When the engine oil temperature is -10°C or less, ensure you have positive LP RPM and maintain maximum crank for 45 seconds, use continuous ignition until the start is complete. Cockpit equipment will perform better if it is allowed to warm to above 65°F for at least 30 minutes.

Procedure

[G450 Airplane Flight Manual §2-08-20]

CAUTION: IF DEICER SOLUTION IS INADVERTENTLY SPRAYED INTO THE ENGINE / APU INLETS OR CONTACTS THE EXHAUST WHEN THE ENGINE OR APU IS IN OPERATION, A POTENTIALLY UNSAFE CONDITION COULD DEVELOP IN THE CABIN. ENGINE / APU BLEED SHOULD BE CLOSED DURING DEICING OPERATIONS TO MINIMIZE THE RISK OF CABIN ENVIRONMENT CONTAMINATION.

APU start

CAUTION: ENGINE STARTING AFTER PROLONGED COLD SOAK REQUIRES SPECIAL CARE AND ATTENTION. PREHEATING THE ENGINE PRIOR TO ANY START IS HIGHLY RECOMMENDED WHEN FACILITIES ARE AVAILABLE.

NOTE: If the airplane has been exposed to an overnight cold soak at temperatures lower than -20°C (-4°F) and the ambient temperature is -20°C (-4°F) or colder at the time of APU start, the batteries should be warmed by external means to raise battery temperature prior to attempting an APU start. Use an external AC power cart, if available, to charge and warm batteries prior to attempting APU start. If no AC cart is available, the batteries must be warmed up prior to APU start. In either case, use the Alternate APU Start Cold Weather procedure.

NOTE: If overnight temperatures were -15°C (5°F) or colder, the APU EGT and RPM displays (cockpit overhead panel) may be unreadable. If preheat capability is available, bring heater hose into the cockpit and preheat the cockpit (with emphasis on the cockpit overhead panel) to get the APU EGT and RPM displays to a readable state. Then proceed with a normal APU start, monitoring the APU EGT and RPM. After APU start, warm the cockpit and cabin to approximately +18°C (+65°F) prior to turning on any cockpit equipment. Cockpit electronic equipment has been demonstrated to have improved performance characteristics if turning the equipment on is delayed until the cockpit and cabin temperature have been maintained above +18°C (+65°F) for at least 30 minutes. For additional information on cold weather operations, refer to Chapter 7 of the G450 Operating Manual.

For APU starts following prolonged cold soak:
Alternate APU Start Cold Weather Procedure
  1. EMERGENCY POWER . . . ARM
  2. LEFT / RIGHT BATTERIES . . . ON
  3. BATTERIES VOLTS . . . CHECK (22V DC MIN)
  4. If external AC power is available, perform step 4. Otherwise, proceed to step 5.
  5. External AC Power . . . ON
  6. APU FIRE Test . . . PERFORM
  7. APU AIR . . . OFF
  8. NAV Light . . . ON
  9. L MAIN BOOST PUMP . . . ON
  10. APU MASTER . . . ON
  11. APU READY Light . . . ILLUMINATED
  12. NOTE: If the APU READY light is difficult to see, wait two (2) minutes before pressing APU START switch.

  13. APU START . . . PRESS (MOMENTARILY)
  14. When APU reaches operating speed (100% rpm):
  15. APU GEN . . . ON
  16. EMERGENCY POWER . . . OFF
  17. NOTE: If the APU GEN switch is already in the ON position when the APU start sequence is initiated, the APU generator will automatically power the bus four (4) seconds after the APU achieves 95% RPM.

    When APU is stabilized at 100% RPM for 90 seconds:
  18. APU AIR . . . ON
  19. NOTE: The APU AIR load control valve is inhibited OFF during APU starts and after APU start for 90 seconds even with APU in the ON position.

    As soon as possible, while the cockpit warms up:
  20. DU 1 . . . NORM
  21. L Fire Bottle Discharge Amber CAS Message . . . VERIFY NOT DISPLAYED
  22. NOTE: APU fire protection is provided by the L Fire Bottle only.

    NOTE: The Essential AC-Bus Fail Amber message can only be checked when operating in battery power.

  23. DU 1 . . . OFF
  24. MFD Display Switching . . . PILOT / COPILOT = NORM
  25. L and R Total Air Temperature (TAT) Probes Airflow . . . CHECK
  26. NOTE: Check for proper aspirated airflow at the aft end of the probe. Steady airflow should be present with the APU AIR ON. If the airflow is not steady or there is some doubt, maintenance action is recommended prior to flight.

  27. External AC (if used for start) . . . OFF
  28. CAUTION: ENGINE STARTING AFTER PROLONGED COLD SOAK REQUIRES SPECAIL CARE AND ATTENTION. PREHEATING THE ENGINE PRIOR TO ANY START IS HIGHLY RECOMMENDED WHEN FACILITIES ARE AVAILABLE.

Engine Start:

    When oil temperature is -10°C or less:

  1. Crank Cycle . . . PERFORM
  2. Normal Engine Ground Start Procedure . . . PERFORM WITH FOLLOWING MODIFICATIONS
  3. CAUTION: BE ALERT FOR POTENTIAL HOT START INDICATIONS.

    Prior to selecting the L / R FUEL CONTROL to run:
    1. Positive LP RPM . . . CHECK
    2. Maximum Crank RPM . . . MAINTAIN FOR 45 SECONDS
    3. NOTE: If the start is aborted, perform a crank cycle prior to attempting another start.

    4. CONT IGN . . . ON UNTIL AFTER ENGINE START COMPLETE
    5. CONT IGN . . . OFF
    After both engines are started:
  4. After Starting Engine Checklist . . . COMPLETE
  5. Engines . . . IDLE UNTIL ALL PARAMETERS ARE NORMAL
  6. NOTE: Minimum oil temperature to accelerate engines for taxi power is -30ºC.

    NOTE: During ground idle power operation at extremely cold ambient temperatures, continuous ignition may be automatically activated concurrent with increased engine bleed. Continuous ignition will be indicated on the engine instruments and increased bleed will result in an audible change in engine noise. Steady state engine operation and performance is not impacted. This condition is self clearing when the throttles are advanced from ground idle.

Cross Bleed Start

Removing the air cart connection with two engines running is not fun, no doubt about it. Doing a cross bleed start gives the line personnel a safer exit path.

Procedure

[G450 Airplane Flight Manual §2-08-40]

    After starting one engine from either APU or an external air supply:

    Now would be a good time to get rid of the external air cart and clear all personnel out of harm's way.

  1. Parking Brake / Pressure . . . SET / 3000 PSI
  2. Check the surface underneath all three landing gear. If the aircraft is on ice a single-engine run up may be enough to move the airplane.

  3. ENGINE BLEED AIR (engine to be started) . . . OFF
  4. ENGINE BLEED AIR (operating engine) . . . ON
  5. Running Engine Power Lever . . . ADVANCE TO 28 PSI BLEED AIR PRESSURE
  6. Make sure there is nothing behind the airplane within reach of the engines at high power.

    CAUTION: ENSURE LP RPM IS NOT SET BETWEEN 60% AND 72%.

    CAUTION: APPROXIMATELY 85% HP RPM IS REQUIRED FOR CROSSBLEED STARTING. ENSURE AREA BEHIND AIRPLANE IS CLEAR BEFORE ATTEMPTING THIS PROCEDURE.

    NOTE: Prior to acceleration above 85% HP RPM, the engine should be idled for four (4) minutes (cold engine) / two (2) minutes (warm engine).

  7. Engine Not Running . . . START USING NORMAL ENGINE START PROCEDURES
  8. After starting other engine:

  9. Power Levers . . . IDLE

Dual Engine Failure - Mid-Altitude

As of December 5, 2013, Revision 36, this procedure in the G450 AFM still uses 200 KCAS as the minimum speed for engine restart, while the limitations section, figure 1-9, correctly notes a minimum speed of 250 KCAS and a maximum altitude of 25,000'.

The 200 KCAS comes from the GV/G550.

What to do? Push over and try to get at least 250 KCAS and attempt the restart as soon as you reach 25,000'.

This procedure seems to assume you are going to get the engines back. If you don't, turn a few pages and study the Dual Engine-out Landing checklist.

Symptoms:

It gets quiet, a lot of numbers decrease (altitude, airspeed), while others increase (cabin altitude, blood pressure).

Analysis:

There are three checklists dealing with dual engine failure:

  • You want this one if you are below 25,000' and can attempt an immediate restart.
  • If you are well above 25,000' and need to get down to that altitude to attempt engine restarts, you probably want the Dual Engine Flameout checklist.
  • If you are even lower, say pattern altitude, it is probably too late for a checklist but you might consider studying the G450 Dual Engine-out Landing checklist before you need it.

Procedures:

[G450 Airplane Flight Manual, §4-06-60]

    In the event that both engines flameout during mid altitude holding (approximately 20,000 ft) perform the following steps immediately:

  1. Pushover . . . Execute to 10° nose down attitude
  2. Airspeed . . . Accelerate to 200 KCAS minimum and continue acceleration to 250 KCAS.
  3. At 200 KCAS:

    This is a mistake, you should do this at 250 KCAS.

  4. Both CONT IGN . . . ON
  5. Both Fuel Controls . . . RUN
  6. Engine Start . . . Monitor on DU 1 and DU 4 Alt Eng Display or on MCDU 1 Back Up Engine Data
  7. If the engine has been cold-soaked, select backup engine instruments (STBY ENGINE) page on MCDU 1. The TGT responses on the STBY ENGINE page will be the first indication of engine start.

    AS ENGINES RESTART

  8. Descent Rate . . . Arrest descent rate by slowing to 200 KCAS.
  9. After one or both engine(s) relight, allow engines to stabilize for one (1) minute.

    CAUTION: WHEN USING CONTINUOUS IGNITION, TO AVOID INADVERTENT ENGINE SHUTDOWN, IDENTIFY THE CONTINUOUS IGNITION SWITCH PRIOR TO SELECTION OF THE L-R CONT IGN SWITCH TO OFF.

  10. Continuous Ignition (Both) . . . OFF
  11. After one (1) minute, set thrust for level flight.

Stick and Rudder

Windmilling hydraulics should provide adequate flight controls at just about every altitude and flyable airspeed.

Dual Engine Flameout

The checklist works for most high altitude situations but you may want to reconsider some of the items if you are thousands of miles from the nearest land. Descending at VMO/MMO to 37,000 feet makes sense to get the APU started, and maybe all the way down to 25,000 feet to get the engines started.

This procedure seems to assume you are going to get the engines back.

If you don't, turn a few pages and study the Dual Engine-out Landing checklist.

Why did both engines quit? In many cases of volcanic ash ingestion, for example, pilots were unable to restart their engines until about 14,000'. If you think you chances are best at a lower altitude and need to stretch your distance, you might consider getting the APU started and flying at a speed closer to maximum glide, which will be about 0.30 AOA.

See Angle of Attack for more on this.

So what's that glide speed come to in knots? There isn't anything in the G450 manual but in the GIV-SP QRH there's this:

images

Symptoms:

It gets quiet, a lot of numbers decrease (altitude, airspeed), while others increase (cabin altitude, blood pressure).

Analysis:

There are three checklists dealing with dual engine failure, you want this one if you are at cruise altitude, well above 25,000' and need to get down to that altitude to attempt engine restarts.

If you are already below 25,000', you probably want the Dual Engine Failure Mid-Altitude checklist. If you are even lower, say pattern altitude, it is probably too late for a checklist but you might consider studying the Dual Engine-out Landing checklist before you need it.

Even if you are en route and end up with this checklist, depending on where you are, you might want to stretch out your distance covered or hurry on down to an altitude where you can attempt a restart. The checklist makes a few assumptions about your situation you may want to think about before executing.

Procedures:

[G450 AFM, ¶ 4-06-40]

  1. Crew Oxygen Masks (100%) . . . DON
  2. Power Levers . . . IDLE
  3. L / R Fuel Control . . . OFF
  4. Descend to Airstart Envelope at VMO / MMO.
  5. NOTE: With both engines out, there is diminished hydraulic power to the flight controls. Use pitch trim as necessary to maintain VMO / MMO in the descent.

  6. Passenger Oxygen Masks . . . MANUALLY DEPLOY
  7. At 37,000 ft or below:

  8. APU . . . START
  9. See Section 3-03-20: APU Inflight Operation – Alternate Electric Power Source.

  10. APU Generator . . . ON
  11. L / R Engine Bleed / ECS Packs . . . OFF
  12. Monitor engine start on DU 1 and 4 Alt Eng Display or on MCDU #1 Back Up Engine Data.

    THERE ARE NO TGT LIMITATIONS ASSOCIATED WITH THIS PROCEDURE.

    At 25,000 ft or below:

  13. L / R Continuous Ignition . . . ON
  14. L / R Fuel Control (one at a time) . . . RUN
  15. FF / TGT Indications . . . MONITOR
  16. Deceleration To 250 Knots . . . START
  17. After one or both engines relight, allow engine(s) to stabilize for one minute.

    After one minute:

  18. Set thrust for level flight prior to reaching 15,000 ft or MEA (Minimum En route Altitude) whichever is higher.
  19. CAUTION: WHEN USING CONTINUOUS IGNITION, TO AVOID INADVERTENT ENGINE SHUTDOWN, IDENTIFY THE CONTINUOUS IGNITION SWITCH PRIOR TO SELECTION OF THE L-R CONT IGN SWITCH TO OFF.

  20. L / R Continuous Ignition . . . OFF
  21. Re-establish normal electrical, ECS, and pressurization configuration.
  22. Fuel Load Balance . . . MONITOR / MAINTAIN
  23. See Section 1-03-80: Fuel Load Balancing.

Stick and Rudder

Windmilling hydraulics should provide adequate flight controls at just about every altitude and flyable airspeed.

Dual Engine-out Landing

This procedure wants you to arrive over the runway and circle until you are 2,500' AGL abeam the touchdown point. This is a fairly standard fighter technique from the U.S. Air Force and Navy. But how you going to get to the runway if you have some distance to go?

Maximum glide happens at about 0.30 AOA.

See Angle of Attack for more on this.

So what's that glide speed come to in knots? There isn't anything in the G450 manual but in the GIV-SP QRH there's this:

images

Regardless of how you get there, you have a few more tools at your disposal.

If you have a long runway, you might want to pad the altitude a little and be prepared to induce a slip on final if you are too high.

If you still have the HUD the flight path vector will let you know how the glide is going.

This procedure has you rely on windmilling hydraulics which will, it says, be good as low as 2.7% HP rpm. The very next procedure in the G450 AFM, Right Engine Failure and Left (L SYS) and Auxiliary Hydraulic System (AUX) Loss of Fluid uses the engine starter to provide sustained brake pressure. Depending on your situation, you might consider doing the same.

Symptoms:

It gets quiet, a lot of numbers decrease (altitude, airspeed), while others increase (cabin altitude, blood pressure).

Analysis:

There are three checklists dealing with dual engine failure, you want this one if the other two have failed you or all this is happening at a very low altitude.

If you are well above 25,000' and need to get down to that altitude to attempt engine restarts, you probably want the Dual Engine Flameout checklist.

If you are already below 25,000', you probably want the Dual Engine Failure Mid-Altitude checklist.

Procedures:

[G450 AFM, ¶ 4-06-70]

    NOTE: Windmilling HP rpm as low as 2.7% provides sufficient flight control power for safe flight. If engine(s) was shut down using the FIRE handle, it will be necessary to reseat the handle to restore hydraulic power. Prior to reseating the FIRE handle, the associated (on-side) FUEL S/O circuit breaker will need to be pulled in order to prevent fuel from being introduced into the engine. (L FUEL S/O: LEER, B-3; R FUEL S/O: REER, B-14).

    CAUTION: IF FIRE HANDLE IS RESEATED AT HIGH ALTITUDE, HYDRAULIC PRESSURE MAY NOT BE RESTORED UNTIL DESCENDING TO LOWER ALTITUDES. MAXIMUM RECOMMENDED ALTITUDE FOR RESEATING FIRE HANDLE IS 25,000 FEET.

  1. APU (if not running) . . . START
  2. APU GEN . . . ON
  3. Starting Point . . . ESTABLISH 5,000 FT AGL OVER LANDING AREA
  4. Flaps . . . 10° (EXTEND WITH AUX PUMP)
  5. To extend flaps when only battery power is available:

    1. EMERG STAB . . . ARM
    2. AUX PUMP . . . ON
    3. Flap Handle . . . MOVE TO DESIRED POSITION
    4. PITCH TRIM . . . DISENG
    5. Manual Trim Wheel . . . USE TO TRIM ELEVATOR CONTROL FORCES
    6. AUX PUMP (when flap movement stops) . . . OFF

    If Electric Elevator Trim is desired once flaps reach selected position:

    1. EMERG STAB . . . OFF
    2. PITCH TRIM . . . ENG
  6. Airspeed . . . VREF FOR 10° FLAPS + 20 KCAS
  7. 180° Position . . . BANK TO ESTABLISH
  8. A 25 degree bank will bring the airplane to a 180 degree position at about 2,500 ft AGL.

  9. Flaps . . . 20° (EXTEND WITH AUX PUMP)
  10. GPWS / GND SPLR FLAP ORIDE . . . ON
  11. Bank Angle . . . MAINTAIN TO HIGH FINAL
  12. The bank angle should be held at 25 degrees or as necessary for turning to high final, depending on winds.

  13. EMER Landing Gear Handle . . . PULL BEFORE TURNING FINAL
  14. NOTE: Pulling EMER Lading Gear Handle first will prevent excessive loads on the windmilling hydraulics.

  15. Landing Gear Handle . . . DOWN
  16. NOTE: Ensure Landing gear handle is DOWN for proper gear position indication.

  17. AUX PUMP . . . ON FOR LANDING
  18. Final Approach Turn . . . 800 TO 1000 FT AGL
  19. Flaps Position . . . VERIFY 20°
  20. Rudder / Brakes . . . USE AS NECESSARY
  21. TO MAINTAIN DIRECTIONAL CONTROL TO STOP

  22. PARK / EMER BRAKE . . . PREPARE TO USE IF REQUIRED

Stick and Rudder

Windmilling hydraulics should provide adequate flight controls at just about every altitude and flyable airspeed. However, . . .

Engine Exceedance

The QRH begins isn't very helpful and leads you to shutting the engine down for what might just be a gauge problem. Unlike most monitoring systems on the airplane, only one of the EVM channels is actively monitored and selecting the secondary system gives you another view you didn't have before. The QRH is also silent on the engine shut down considerations; knowing what the AFM has to say could be critically important.

The FSI view: you can change accelerometers and if the warnings go away, the primary was bad and you can press on.

My view: that is a pretty expensive engine and you have two of them. If the secondary says the engine is okay and the primary says its bad, how do you know which is correct? I would take into consideration the primary could be bad and continue the investigation. If there are no other abnormal indications, press on. If the primary says bad, the secondary says good, I would look for a tie breaker. Abnormally high oil pressure, for example, could be a reason to bring the thing to idle and land that way.

Symptoms:

images

Engine Exceedance, L-R

Besides the CAS you should have high EVM's on the engine instruments. You might also have high fuel temperature, other abnormal indications, or actual vibration in the aircraft.

Analysis:

[G450 AOM, ¶2A-77-10 ¶1.B.] The EVM system detects anomalies in engine rotational balance through dual accelerometers mounted side by side on the engine exterior. Only one (primary) accelerometer actively provides signals to the EVM system - the other (secondary) unit provides redundancy and may be selected for signal input in order to confirm abnormal vibration readings.

[G450 AFM, ¶ 4-06-10] Shut engine down when the following occurs:

  • Engine Fire.
  • Extreme engine vibration is felt in airplane.
  • Excessive or uncontrollable power loss.
  • Sudden increase or decrease in oil pressure beyond limits.
  • Sustained high oil temperature above limits.
  • Sudden uncontrollable increase in TGT beyond limits.
  • Any other condition that indicates the advisability of engines shut down.

NOTE Engine Vibration Monitoring (EVM) indications alone should not be used as criteria for engine shutdown. If EVM exceeds 0.60 LP and / or 0.60 HP, retard power lever to achieve vibration below this value. If vibration is accompanied by other failure indication, shut down engine. In icing conditions, vibrations may exceed alert level without other abnormal indications and are considered normal.

QRH Procedure:

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[G450 QRH, ¶MB-26]

Engine Fail - Drift Down

Nine out of ten Gulfstream pilots who have never tried this in the simulator (or in the airplane) will get this wrong almost immediately because of one button in the cockpit: FLCH. They will press that button and watch the operating engine go to idle. After some cussing they will disengage the autothrottles, reengage FLCH and watch the pitch oscillate wildly up and down while they waste valuable altitude. Here's how to get it right the first time:

  1. Advance the operating engine to maximum continuous. You can get this quickly from the TRS page of the display controller:
  2. images
  3. Call for QRH driftdown chart (EB-16) while setting 600 fpm down vertical speed. You are probably cruising at 0.80M and in the G450 your drift down speed is more than likely 0.80 or less so you need to do this immediately.
  4. Once the driftdown chart is found, set correct driftdown speed and make note of the target altitude. Fine tune vertical speed to maintain the correct airspeed.
  5. Note: the G450 drifts down more rapidly than the GV/G550, which typically start down around 300 fpm. FLCH is not recommended since speed deviations can result in reduced longitudinal performance.

  6. At target cruise altitude allow speed to decay to "Start Cruise" speed.
  7. Turn aircraft towards a divert airport as the situation permits.

There is more to driftdown than just this. Refer to ETOPS for more on how to get your single-engine Gulfstream to a landable surface. Also take a look at Engine Out Considerations.

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QRH EB-16 → You should have this page number memorized

Procedure

[G450 AOM, ¶11-05-10 ¶1.A.] To attain the driftdown performance shown, the recommended driftdown procedure described below must be followed.

  1. At the failure of one engine, Maximum Continuous Thrust is set and held on the operating engine during any deceleration, if required to reduce the speed to the entry descent Mach. Any deceleration should be performed at the initial altitude before the start of descent.
  2. The descent Mach number should be maintained until the calibrated speed is intercepted. The calibrated speed is then held down to the final driftdown altitude (identified as “Cruise Altitude”).
  3. At the final driftdown altitude, a 100 FPM rate of climb capability will be possible at Maximum Continuous Thrust at the “Start Cruise” speed shown.
  4. Moderate thrust reductions are required at the “Cruise Altitude” to stabilize at the “Start Cruise” calibrated airspeed.

Engine Out Approach

The Gulfstream philosophy on engine-out approaches has changed completely over the years. In the GIII the idea was to fly the airplane with partial flaps until landing was assured. The idea, of course, was you didn't have enough power to go around with full flaps. The GIV and GV initially used the same procedure, with the GV recommending the use of full flaps on final approach with the option to fly with less.

The problem? The engines would not be commanded into a high idle setting with 20° flaps and in the event of a missed approach the engines would catch up all at once and present the pilot with a huge control problem. Other issues included a high deck angle and EVS system aim. The aircraft had more than enough power to fly the approach with full flaps and even if the flaps jammed there during a missed approach, the aircraft had enough power to cope. Now the GIV, GV, and the G450/G550 series all recommend using full flaps for an engine out approach.

For more about engine failures, take a look at Engine Out Considerations.

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The G450 has more than enough power to handle engine-out approaches with the same procedures when operating with both engines. There are two AFM limitations worthy of note:

  1. 1-22-20: Coupled Go-Around
    Single engine autopilot coupled go-around is not approved.
  2. 1-22-70: Use of Autothrottle during Single Engine Approaches
    Use of the autothrottle during single engine approaches is prohibited.

With a left engine failed you may need the AUX hydraulic pump or PTU system for brakes, and in the case of the AUX pump you will want the flaps fully set prior to touchdown as moving flaps will fully tax the pump's 2 gpm output, robbing the brakes of any pressure.  You will have reverse thrust available on the operating engine.

Therefore . . .

Fly normal approach airspeeds and configure at the usual points as required for the approach.

Sometime before the final approach fix disengage the autothrottle and the autopilot.  With the autopilot off at this point, you don't run the risk of forgetting it during the missed.

Engine Out Missed Approach

The engine-out missed approach can be a handful and requires a bit of smoothness and patience. You will be starting with very little rudder and end up with just about all of it, but making the transition can be a challenge. As the power comes up the aircraft will roll and yaw and most pilots have a tendency to over-correct and end up with oscillations in all axis as a result.

Your best bet is to smoothly add about half the rudder and freeze it there while you attempt to maintain bank angle with ailerons. As things settle down you can fine tune the rudder, knowing most of it will have to come out as the power comes back when you level off.

For more about engine failures, take a look at Engine Out Considerations.

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Procedurally, a one-engine missed is flown the same as a two-engine missed. Flying it, however, is an exercise in smoothness.

  • Autothrottles will be off.  Autopilot should be off during the approach and must be off during the missed approach.
  • Smoothly push the operating power lever all the way forward and allow the FADEC to control the engine.
  • Add rudder at the same rate. If you are too aggressive with the rudder, you will have a difficult time controlling heading.
  • Do not touch the speed button at all; the commanded VREF+10 will stay until 1500'.
  • The GA button only works below 16,500' MSL and below 2,000' AGL and below 200 knots. It results in a wings level pitch up of 8° then attempts to hold the commanded speed but no higher than 17°.
  • Once at a safe altitude, flaps can be retracted at any time, retract speed is VREF+10.

Engine Start - No IGN

IGN Icon

Once the engine is spinning and you select the fuel control to RUN, the first thing you should see on the engine CAS is an IGN icon:

images

If you don't see the IGN icon, the problem may be that you've selected CRANK instead of START and the FADEC will not be turning on the ignitors for you.  You can at this point manually select that engine's ignition if you are fast enough. But if you've had more than a few seconds of fuel in the engine without ignition, you should probably abort the start and execute a few dry cranks to purge the fuel.

Bad Igniter

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Check for a popped ignition circuit breaker first.

The IGN icon will also fail to illuminate if the selected igniter or ignition channel has failed. Each engine has two igniters and each igniter can be powered by two different ignition channels:

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A failure in a single channel or igniter can lead to no IGN due to the logic of the FADEC, which selects different channels and igniters for each start, according to the following progression:

  • Channel A, Igniter 1
  • Channel B, Igniter 1
  • Channel A, Igniter 2
  • Channel B, Igniter 2

So, for example, if Igniter 2 had gone bad right after a successful start using Chanel B, Igniter 2, the next two starts using Igniter 1 would also be successful. The following start, using Channel A, Igniter 2 will fail. Aborting that start and trying again will also fail, since that iteration also uses Igniter 2. Selecting continuous ignition will use both igniters, guaranteeing ignition.

Engine Start - SVO Fails to Open

The G450 starter valve and starter are different than what you may have seen on the GIII, GIV, and GV so you need to leave some of that knowledge behind. You need to understand that the starter valve has air pressure against it regardless of the bleed valve position and that it takes air pressure and electricity to move the valve. You can follow QRH EB-20 / AFM 3-09-20 procedures and still end up with an engine that isn't running, or you can help yourself out with some good procedures during the start attempt and troubleshooting immediately following.

  • As soon as you press MASTER START you should hear the airflow of the air conditioning cut in half, you should see the OFF icon in the R PACK switch, and you should see the bleed manifold pressure go up. Now you know the MASTER START switch works and you are getting air to the manifold which means you are getting air to the start valve. If you don't, you probably have a popped circuit breaker or bad switch.
  • As soon as you press the R START or L START switch you should hear airflow of the air conditioning go away completely, you should see the OFF icon in the L PACK switch, you should see the SVO icon, and you should see HP rotation. If you don't, you probably have a popped circuit breaker, a bad switch, or failed starter valve.
  • If the SVO icon does illuminate but there isn't any rotation, you may have a mostly closed starter valve or you could have ice in the engine cowl keeping the HP compressor from spinning.

Now you have an idea where to begin trouble shooting. If you decide you have a bad start valve you have a decision to make. If you read G450 QRH NG-45 you can manually open and then close the starter valve, a fairly risky operation. You've heard guys like me have done this on earlier Gulfstreams and lived. But you've also heard it is much safer to "exercise" the valve to free it up and then attempt a normal start. I've done this on a GIII and it works great. But wait...

[G450 Maintenance Manual, §80-11-03 ¶1] THIS MANUAL OVERRIDE PROCEDURE SHOULD ONLY BE DONE IF THERE IS BLEED AIR PRESSURE TO STARTER AIR VALVE FROM OPERATING AUXILIARY POWER UNIT, ANOTHER ENGINE RUNNING OR RUNNING GROUND START CART CONNECTED TO AIRCRAFT EXTERNAL AIR CONNECTION. IF BLEED AIR IS NOT PRESENT AT INTAKE OF AIR START VALVE, DAMAGE TO STARTER AIR VALVE CAN OCCUR.

The G450 Operating Manual used to allow the practice, stressing that there should not be any air present at the valve but that changed late 2012:

[G450 Aircraft Operating Manual, §09-03-40 ¶1.C.] THIS PROCEDURE CAN ONLY BE ACCOMPLISHED IF APU AIR, CROSSBLEED AIR OR EXTERNAL AIR IS PRESENT AT STARTER AIR VALVE. FAILURE TO COMPLY MAY CAUSE DAMAGE TO STARTER AIR VALVE, STARTER OR ENGINE.

I've come to the conclusion, though I think we as pilots can do it safely, we should not. G450 Quick Reference Handbook, page NG-19 says "Procedures for manually overriding the starter air valves on the G450 are included to enable the flight crew to assist and supervise ramp service personnel when the aircraft is away form its fixed base of operations." It looks like the intent of putting the section into the QRH is to give pilots a way to instruct "ramp service personnel" — just make sure you know how it's done!

Symptoms

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Figure: SVO, from Eddie's notes.

The first thing you should see when you press START is an SVO (Start Valve Open) icon on the engine CAS.

If the SVO fails to open, you may get an SVO indication with little to no rotation, or no SVO indication at all.

Analysis

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Photo: Starter and SVO, from Eddie's aircraft.

[G450 Aircraft Operating Manual, §2A-80-10, ¶2.A.] The primary element of the SAV is a butterfly valve controlled by a solenoid. The valve is normally held in the closed position by an integral spring and the pressure of air within the aircraft pneumatic supply manifold directed against the valve. When the SAV is commanded open by the EEC during engine start, the electrical open signal is provided to the valve solenoid that subsequently opens an internal chamber on the SAV to admit pneumatic manifold air to the open side of the valve. Pneumatic pressure overcomes the loading of the integral spring and moves the butterfly valve open, admitting pressurized air into a duct running forward on the engine to the starter turbine.

[G450 Aircraft Operating Manual, §09-03-40, ¶1.A.] If engine fails to start but IGN and SVO icons are displayed, the failed closed start valve may be stuck due to condensation and/or corrosion. The start valve indication comes on with 6° of valve rotation; therefore, the start valve open indication (SVO) may be displayed but the valve may be almost fully closed.

Procedures

[G450 Airplane Flight Manual, §3-09-20]

  1. Start Master . . . OFF
  2. Circuit Breakers . . . Check / Reset
  3. APU AIR / External Air . . . On / Connected
  4. BLEED AIR Pressure . . . Check 28 PSI minimum
  5. If bleed air is available and pressure is adequate:

  6. Engine Start . . . Re-Attempt
  7. If start valve does not open:

  8. Engine Start . . . Abandon

Engine Start - SVO Fails to Close

Having a starter valve fail to close in the GIII, we were told, risks spraying starter parts as shrapnel and was considered highly dangerous. I'm not so sure but I do know it can cause a lot of damage if you don't follow the correct shutdown procedure. You should have this G450 procedure memorized.

Symptoms

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Amber flashing SVO icon on engine instruments near HP RPM after normal starter cutout speed.

CAS

None.

Analysis

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Diagram from the G450 FlightSafety Maintenance Training Manual.

The start valve should begin to close at 42% HP rpm and the blue SVO icon should go out when it is fully closed, around 48% HP rpm. If the valve does not fully close, the icon should turn amber and start to flash. Further engine operation risks damage to the starter and engine.

The diagram shows a cross section of the starter. The inner spool with the ratchets is attached to the starter, the outer spool is attached to the engine. The tool spools are connected by the three pawls, which are spring loaded inward to contact the starter. Starter Air Valve pressure also pushes the pawls inward. When the engine speed exceeds the starter speed, the centrifugal force on the pawls should hold them clear once the starter air valve closes.

If the pawls fail to disengage, the engine may speed ahead of the starter causing the pawls to continuously ratchet around the starter, damaging the ratchet teeth and pawls. Or it could simply overspeed the starter, damaging its bearings. If you attempt to shut the engine down with the air still engaged, you have the opposite problem, the decelerating engine fighting the starter still spinning.

The proper course of action is to remove all air pressure from the starter and then shut the engine down. The best result would be for the pawls to disengage. Failing that, shutting the engine down should allow the starter to spool down before it is damaged.

More about the starter: G450 Powerplant Starter.

Procedures

[G450 AFM, ¶ 3-09-30]

If the amber flashing SVO icon is displayed by ground idle HP RPM, proceed as follows:

  1. START MASTER . . . PRESS / LIGHT OUT
  2. L / R ENG BLEED AIR . . . OFF
  3. APU (or External) BLEED AIR . . . OFF/

    When bleed air pressure stabilizes at minimum value (after 30 seconds):

  4. Affected Engine FUEL CONTROL Switch . . . OFF

Engine Start SVO Manual Operation

We used to teach this to pilots in the Air Force but pilots were expendable and health care was free. The G450 QRH has the procedure (page NG-19) but it says this is so you, the pilot, can "assist and supervise ramp service personnel when the aircraft is away form its fixed base of operations."

Is the "ramp service" mechanic going to know how to do this just reading four pages in the QRH? But if the chips are down and you need to get the engine running, this is a way to do it. The problem is that the procedure in the QRH is abbreviated and even the full procedure in the maintenance manual [G450 AMM, ¶80-11-03] isn't all that clear unless you have a G450 mechanic's level of knowledge. So even though it is in the QRH, even though you are a graduate of a 3-week course on aircraft systems, you need to know the procedure to teach the procedure.

Study Material

Good to know stuff:

  1. G450 Powerplant
  2. G450 SVO Fails to Open
  3. [G450 AOM, ¶2A-80-10], G450 Engine Starter System
  4. [G450 QRH, ¶NG-19], Manually Overriding Starter Air Valve

QRH Procedure

[G450 QRH, ¶NG-22] (Make sure you read NG-19 through NG-23]

(1) Allow at least five (5) minutes for engine to cool.

(2) Select and brief engine start procedure to be used.

You should go through the entire procedure. If you are going to do a normal engine ground start, for example, brief that you are going to select the START MASTER, L START (or R START), which energizes the starter valve, and then signal the ground person to move the valve. Brief how you will signal for the ground person to release the valve and how he or she can notify you if the valve fails to close.

(3) Position one crewmember in cockpit to perform engine start and to direct opening and closing of valve.

(4) Establish communication with crewmember in cockpit.

You probably aren't travelling with a comm cord so you are going to have to come up with something else. From the right engine you can have the inside pilot turn the ailerons full right as a signal to to open the valve and center the ailerons to close the valve. If the starter valve fails to close, you would have to run up to the cockpit to tell the inside pilot to abort the start. From the left engine you will not be able to see the ailerons. In older Gulfstreams we used the ground spoilers but that isn't an option in a G450 without the right engine running. You can either start the engine or use the flaps. My suggestion: don't do a full start, do a crank cycle and allow the outside crew to time for two minutes. This exercises the valve and is much safer since there is not fuel or ignition. Once the valve is exercised it should work for a normal start.

(5) Gain access to malfunctioning starter air valve through appropriate access door:

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  • Left Engine: Access Door 412BB (Fwd Inboard Door On Lower Cowl)
  • Right Engine: Access Door 422BB (Fwd Outboard Door On Lower Cowl)

(6) On forward end of starter air valve, locate manual drive shaft.

You may need a flashlight and it helps if you know what you are looking for. (It looks different from the access panel than it does on drawings and photos without the cowl in the way:

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Here's what the start valve looks like, close up:

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(7) Visually ensure starter valve is in CLOSED position by verifying index pointer on manual drive shaft is aligned with CLOSED. NOTE: An index pointer is also located on the starter air control valve, on aft end of starter air valve.

The valve is closed in the photo above. Notice the notch in the bolt is vertical, pointing to the upside-down word "CLOSED" and not the word "OPEN" to the left. Both words will be nearly unreadable from the vantage point of the access panel.

(8) When valve is confirmed in CLOSED position, direct crewmember in cockpit to begin engine start procedure. NOTE: Ensure starting air is present at malfunctioning valve before manually opening valve.

Air will be present at the starter any time there is bleed air in the manifold — from the APU, the other engine, or an air cart — but you may damage the starter valve if you manually move it without air.

At this point the cockpit pilot hits either the MASTER START or MASTER CRANK switch followed by the appropriate L or R START switch.

(9) Upon direction by crewmember in cockpit, use tool to position manual drive to OPEN and hold. This opens starter air valve.

This should be an almost 90° turn clockwise. G450 AMM 80-11-01 notes this takes considerable effort without air pressure but as long as the cockpit crewmember has activated the start switches, it shouldn't be too hard.

(10) Upon direction by crewmember in cockpit, release manual drive to allow starter air valve to return to CLOSED position. NOTE: Ensure valve returns to CLOSED position when released. If valve does not automatically move to CLOSED position, see Start Valve Failure To Close After Engine Start, page EB-29.

The cockpit crew needs to signal the ground crew with enough lead time to ensure the start valve is closed by 42% HP. This isn't as bad as it was in the GIII, where an oversped starter could fling itself apart and hurl shrapnel, but an oversped G450 starter will overheat and could damage itself.

You should be able to release the valve and it should move itself back to the closed position. It is spring-loaded closed with a ratchet mechanism which does this slowly. The book does not allow you to force it closed, if it won't close on its own, it is broken.

(11) Ensure all tools and equipment are removed from area.

(12) Close and secure starter air valve access door.

Engine Time Limited Dispatch

When the GV came out many would preach that you could always dispatch on a blue CAS message and of course that was always wrong, despite what is still printed in the manual.

See G450 Warnings, Cautions & Notes for more about this.

Then along came the "LTD" message. LTD, Limited Time Dispatch, at first meant you have a limited time to dispatch. No problem! Well that has changed too. You usually get these right after engine start and will be tempted to look it up after takeoff. (Especially if you are paired with an old GV guy like me.) But don't do it. Pull out the QRH and bring up the CMC. You might be grounded.

QRH Procedure

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Page MC-31 of the G450 QRH gives you some CMC work and depending on the results, you may be grounded. Years ago the list had no groundable items and now, as of the Summer of '13, there are more than ten things that should give you pause.

Bottom Line #1: Just because it is a blue CAS message does not mean you can take off.

See G450 Warnings, Cautions & Notes for more about this.

Bottom Line #2: You need to check your current QRH to make sure what you see on the CMC isn't bad news.

Translation

STD

The FADEC Short Term Dispatch (STD) blue CAS message means there is a fault in channel A and/or B of the FADEC system. The message begins as L(R) Engine Maintenance 150 to let you know you have 150 hours before the message turns amber. The number, 150, counts down and when it reaches 0 it will go amber. Of course this leads you to believe that you are okay until then, and you might be. But if the CMC reveals an item shown on the QRH list, you are not.

LTD

The FADEC Long Term Dispatch (LTD) blue CAS message also means there is a fault in channel A and/or B of the FADEC system. The message, according to literature from Rolls-Royce, begins as L(R) Engine Maintenance LTD but we have seen L(R) Engine Maintenance 500. Rolls-Royce says "There is neither an EEC nor an aircraft AVIONICS Logic that ensures automatic upgrade to the next higher EICAS message when the time (500 flight hours) has elapsed.

Rolls-Royce Information

Chances are these messages could leave you, your mechanic, and your Gulfstream tech rep confused. You may end up on the phone with Rolls-Royce. They will refer you to Rolls-Royce Time Limits Manual Task 05-20-03-800-801. It may not answer all your questions, it did not do the trick for us, but it will get you started.

Crew Actions

  1. Refer to the QRH.
  2. Check the CMC, per the QRH.
  3. If the indicated message is not on the QRH list, make a note of the flight hours and the message and press on.
  4. If the indicated message is on the QRH list, you may not dispatch.

External Air Start

You are saying to yourself, "this is pretty straightforward." But when you have a bunch of impatient passengers breathing down your neck it may not work the way you think. Consider the following:

  • If you have AC power, things are good. You just need to make sure the external air source doesn't overwhelm the airplane. The engines wants at least 28 psi, an air cart that puts out 60 psi might be okay but much more than that could be bad news for the air cycle machines as well as the engines.
  • If you don't have AC power and will be doing a battery only start, where the heck is 2-08-270? Well, it is in the AFM but you can find the exact procedure in the QRH, page NG-17.
  • Do you really want to start both engines using external air? The hook up is underneath both engines, perfectly centered. You can easily start the right engine with the air cart off to the left. You should disconnect at this point to get the cart and the line personnel out of harms way before you start the left engine using cross bleed.

Procedure

[G450 Quick Reference Handbook pg. NG-28]

CAUTION: Ensure electrical power is "ON" (APU/EXT AC) prior to applying air from an external air source.

Note: For battery only starts go to 2-08-270, Engine Start - Battery Power Only.

  1. Before Starting Engines Checklist . . . PERFORM
  2. External Air Source . . . CONNECTED
  3. Normal Engine Ground Start . . . PERFORM
  4. Either engine, or both in turn, may be started using an external air source.

Techniques and Considerations

Consider where you want to place the air cart and how to keep the ground crew out of harms way. You might consider placing the cart to the left of the airplane for the right engine start and then disconnecting the cart and getting everything and everyone out of the way for the left engine start.

You might want to have a pilot on the ground supervising the right engine start and rehearse your visual signals between pilots.

The external air door is not on the Doors Synoptic page, you will have to trust the guy on the ground to close it.

If the starter valve fails to close you are going to have to shutdown or disconnect the air cart to help the starter spin down to minimum speed. (Closing the bleed air and isolation valves may help, but it would be better to have an open bleed duct with no pressure.)

FADEC Alternate Control Mode

The computer that controls your engines like to do it using EPR but if something prevents that, it can also use LP RPM. This could happen because something goes wrong with the EPR system or some of the electrons between the FADEC and MAUs get lost. If this is the case, you can easily get everybody running things on EPR again. Here's how.

Symptoms:

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Figure: Engine Alt Control Soft Reversion, from FSI G450 PTM, Figure 7-49.

[G450 Quick Reference Handbook, Page MC-30] Blue CAS Message: Engine ALT Control, L-R.

They say you should get a black on amber ALT indication next to the LP RPM indicator on the engine instruments, an amber EPR pointer, and either amber EPR indications or dashes.

Analysis:

[G450 Airplane Flight Manual, §03-05-10]. If FADEC detects a failure which prevents continued operation in the primary Engine Pressure Ratio (EPR) control mode, it will automatically perform a soft reversion to the alternate (LP) control mode. The flight crew must then perform a hard reversion of both engines to the alternate control mode, using the display controller, to alleviate throttle stagger problems. NOTE: EPR indication may be lost for the engine that has experienced a soft reversion to the alternate control mode.

Procedure:

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Figure: Engine Alt Control Reselect EPR Mode, from Eddie's notes.

[G450 Airplane Flight Manual, §03-05-10]

  1. Display Controller . . . SELECT SENSOR MENU
  2. Sensor Menu . . . SELECT ENG ALT CTRL
  3. Affected Engine Power Lever . . . MID RANGE
  4. Affected Engine (L or R) CTRL . . . ALT
  5. Note: Attempt to reselect EPR Mode if Alternate Control Mode occurs for no apparent reason. If engine control returns to EPR mode no further action is required. If the engine doe not return to EPR mode proceed to step 5.

    You must "hard select" the ALT position before attempting to return it to EPR mode.

  6. Affected Engine Power Lever . . . AS REQUIRED
  7. Opposite Engine Power Lever . . . MID RANGE
  8. Opposite Engine (L or R) CTRL . . . ALT
  9. This ensures that both power levers will match.

    NOTE: EPR indication will still be presented for the opposite engine, even though it is now controlled by the alternate control mode. Refer to LP charts in Section 5 for limit LP settings or match LP RPM to engine with valid EPR indication.

  10. Opposite Engine Power Lever . . . AS DESIRED
  11. NOTE: Takeoff in Alternate Control Mode is prohibited. Autothrottles willbe inoperative.

FADEC Revert to Alt Control

This happens now and then, usually after APU start. You cannot takeoff and you shouldn't start the engines when the FADEC is in the ALT mode. The switch is easy. The procedure in flight has gotten easier — it use to require bringing the power lever all the way to idle — and it may not be anything to worry about. But if it happens a lot, you might have other issues worth troubleshooting.

Symptoms:

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If engine control is not in EPR mode, there will be a blue “L-R Engine ALT Control” Engine 1/6 page and an amber ALT annunciation on the CAS Page.

Analysis:

[G450 Aircraft Operating Manual §2A-76-10] The Full Authority Digital Engine Control (FADEC) provides independent engine performance control and monitoring in response to flight crew switch position and power lever position commands. Each FADEC communicates with the Modular Avionics Units (MAUs) over ARINC-429 data buses to receive Air Data Module (ADM) information from aircraft environmental systems such as the pitot static and Total Air Temperature (TAT) probes. Each FADEC also transmits data to the MAUs and Monitor and Warning System (MWS) for use in providing synoptic and system window displays of engine performance as well as engine related Crew Alerting System (CAS) messages.

[G450 Aircraft Operating Manual §2A-76-30 ¶1.] Since actual engine thrust can only be measured in a test facility, a surrogate measurement of thrust is used to manage engine power. The primary thrust setting reference on the Engine window(s) display is Engine Pressure Ratio (EPR). EPR is defined as the ratio of pressure sensed at the exit of the High Pressure (HP) compressor to the pressure of the ambient atmosphere as sampled within the engine bypass air duct. The ratio measures the increase in ambient pressure generated by the action of the engine compressor stages and the energy of combustion driving the engine turbine stages. EPR is measured by the engine EEC and communicated to the Modular Avionics Units (MAUs) for use by the display systems.

The EPR value is not a true indication of actual engine thrust since it does not measure the propulsive force generated by the LP fan stage air that effectively contributes a thrust component equivalent to some turbopropellers. EPR is used for thrust management because it most accurately measures the internal forces of the engine compressor and turbine stages.

If a malfunction prohibits EPR measurement by the engine EEC, an alternate method of thrust management is control of the speed of the LP rotor (N1). LP rotor rpm provides a convenient method of engine control since it is easily measured, however, like EPR, it does not reflect actual engine thrust and has the additional disadvantage of being unable to directly determine engine combustion forces since the LP rotor is not mechanically driven by the High Pressure (HP) turbine.

[Gulfstream Video] A video from Gulfstream explains how the FADEC can power up in ALT mode if battery voltage during APU start falls too low: FADEC Reverting to ALT.

The FADEC normally uses EPR to control the engine. EPR information can disappear if a probe's data becomes unavailable, an MAU loses power momentarily, or a host of other reasons. If this happens, the FADEC riverts to HP information, the so called "Alternate Mode" of operation. You cannot start the engines in this mode.

Procedure:

[Gulfstream G450 Quick Reference Handbook pg. EB-32]

    If FADEC detects a failure which prevents continued operation in the primary Engine Pressure Ratio (EPR) control mode, it will automatically perform a soft reversion to the alternate (LP) control mode. The flight crew must then perform a hard reversion of both engines to the alternate control mode, using the display controller, to alleviate throttle stagger problems.

    NOTE: EPR indication may be lost for the engine that has experienced a soft reversion to the alternate control mode.

  1. Display Controller . . . SELECT SENSOR MENU
  2. SENSOR Menu . . . SELECT ENG ALT CTRL
  3. Affected Engine Power Lever . . . MID RANGEv
  4. Affected Engine (L or R) CTRL . . . ALT
  5. Affected Engine Power Lever . . . AS REQUIRED
  6. Opposite Engine Power Lever . . . MID RANGE
  7. Opposite Engine (L or R) CTRL . . . ALT
  8. This ensures that both power levers will match.

    NOTE: EPR indication will still be presented for the opposite engine, even though it is now controlled by the alternate mode. Refer to LP charts in AFM Section 5 for the LP settings or match LP RPM to engine with valid EPR indication.

  9. Opposite Engine Power Lever . . . AS DESIRED
  10. NOTE: Attempt to reselect EPR Mode if Alternate Control Mode occurs for no apparent reason.

    NOTE: Takeoff in Alternate Control Mode is prohibited. Autothrottles will be inoperative.

Left Engine Failure and Right Hydraulic Failure

With the left engine starter providing windmilling hydraulics, this is just like landing with Loss of Right Hydraulics Pressure or Fluid with the exception you need to turn the starter on in the last ten minutes. You just need to give the system time between actuation of hydraulic items.

Symptoms:

The left engine has failed but is windmilling, the synoptics show you have no hydraulic pressure or quantity on the right.

Analysis:

You have hydraulic pressure on the left so long as the engine is windmilling, you can keep the pressure up through the landing using the left engine starter.

Procedures:

[G450 AFM, ¶ 4-06-90]

    NOTE: This procedure covers loss of both Left and AUX Hydraulic Systems with a windmilling right engine. Windmilling HP rpm as low as 2.7% provides sufficient flight control power for safe flight. Flight control inputs should be minimized (20° bank angles and ±10° pitch have been demonstrated) and a “No Flap” landing performed. If the windmilling engine was shut down using the FIRE handle, it will be necessary to reseat the handle to restore hydraulic power. Prior to reseating the FIRE handle, the R FUEL S/O circuit breaker will need to be pulled in order to prevent fuel from being introduced into the engine.

    CAUTION: IF FIRE HANDLE IS RESEATED AT HIGH ALTITUDE, HYDRAULIC PRESSURE MAY NOT BE RESTORED UNTIL DESCENDING TO LOWER ALTITUDES. MAXIMUM RECOMMENDED ALTITUDE FOR RESEATING FIRE HANDLE IS 25,000 FEET.

    The autopilot may be used, if available.

  1. Airspeed ... MAINTAIN 200 KCAS MINIMUM UNTIL ESTABLISHED ON A LONG STRAIGHT-IN FINAL APPROACH TO LONGEST, WIDEST RUNWAY AVAILABLE WITH MINIMUM CROSSWIND COMPONENT
  2. Lateral Hardover Protection ... DEACTIVATE LATERAL HYD S/O
  3. When ready to configure:

  4. Flaps ... 20° (Extend using Aux Pump)
  5. Airspeed ... SLOW TO 175 KCAS
  6. Landing Gear ... PERFORM EMERGENCY EXTENSION
  7. NOTE: See Landing Gear Failure To Extend

  8. Flaps ... 39° (Extend with Aux Pump)
  9. NOTE: If the flight crew elects to land at flaps 20°, fly the approach at VREF for 20° flaps +10 knots. See AFM Section 5, Performance, for landing distance in the flaps 20° configuration.

    NOTE: If strong winds are present, add to VREF ½ of the steady state wind plus the full gust to a maximum additive of 20 knots.

  10. Ground Spoilers ... OFF
  11. L ENGINE BLEED ... OFF
  12. L ENGINE PACK ... OFF
  13. AUX Pump ... ON
  14. CRANK MASTER ... ON
  15. START Switch ... L ENGINE
  16. Airspeed ... FLY NORMAL NO-FLAP APPROACH SPEED
  17. NOTE: Nose wheel steering operation should be available with a windmilling left engine being cranked in accordance with the steps above. It is possible, however, that high demands on the left hydraulic system could decrease system performance.

    After landing:

  18. Speed Brakes ... EXTEND SLOWLY (3 SECONDS MINIMUM)
  19. NOTE: Starter will motor windmilling engine at approximately 25 to 30% HP providing adequate steady hydraulic pressure. Starter time limits can be extended up to 10 minutes in flight.

    NOTE: A go-around has not been demonstrated in this configuration.

Right Engine Failure and Complete Left/Aux Hydraulic Failure

With the right engine starter providing windmilling hydraulics, this is just like landing with Loss of Left and Aux Fluid with the exception you need to turn the starter on in the last ten minutes. The hardest part about this procedure having patience with the parking brake. Think of the many times you've landed the airplane and didn't touch the brakes until taxi speed.

  • Plan a long final approach to get the landing gear extended using the emergency system.
  • Putting the airplane down firmly kills kinetic energy.
  • While you still have rudder effectiveness, drift the airplane to the downwind side in anticipation of the aircraft into the wind once you lose rudder effectiveness. If you have a choice, having a wind from the left allows you to use right engine reverse to counteract the weather vane.
  • Slowly pull the parking brake until pressure is indicated. Slowly work your way up to 400 and then leave it there. As the brakes heat up that same pressure will become more and more effective. You shouldn't have to go above that until you are at taxi speed.

Symptoms:

The right engine has failed but is windmilling, the synoptics show you have no hydraulic pressure or quantity on the left.

Analysis:

You have hydraulic pressure on the right so long as the engine is windmilling, you can keep the pressure up through the landing using the right engine starter.

Procedures:

[G450 AFM, ¶ 4-06-80]

    NOTE: This procedure covers loss of both Left and AUX Hydraulic Systems with a windmilling right engine. Windmilling HP rpm as low as 2.7% provides sufficient flight control power for safe flight. Flight control inputs should be minimized (20° bank angles and ±10° pitch have been demonstrated) and a “No Flap” landing performed. If the windmilling engine was shut down using the FIRE handle, it will be necessary to reseat the handle to restore hydraulic power. Prior to reseating the FIRE handle, the R FUEL S/O circuit breaker will need to be pulled in order to prevent fuel from being introduced into the engine.

    CAUTION: IF FIRE HANDLE IS RESEATED AT HIGH ALTITUDE, HYDRAULIC PRESSURE MAY NOT BE RESTORED UNTIL DESCENDING TO LOWER ALTITUDES. MAXIMUM RECOMMENDED ALTITUDE FOR RESEATING FIRE HANDLE IS 25,000 FEET.

    The autopilot may be used, if available.

  1. Airspeed ... MAINTAIN YAW DAMPER INOP SPEEDS OR 200 KCAS MINIMUM UNTIL ESTABLISHED ON A LONG STRAIGHT-IN FINAL APPROACH TO LONGEST, WIDEST RUNWAY AVAILABLE WITH MINIMUM CROSSWIND COMPONENT
  2. Lateral Hardover Protection ... DEACTIVATE LATERAL HYD S/O
  3. When ready to configure:

  4. Airspeed ... SLOW TO 175 KCAS
  5. Landing Gear ... PERFORM EMERGENCY EXTENSION
  6. NOTE: See Landing Gear Failure To Extend

  7. R ENGINE BLEED ... OFF
  8. R ENGINE PACK ... OFF
  9. CRANK MASTER ... ON
  10. START Switch ... R ENGINE
  11. NOTE: Starter will motor windmilling engine at approximately 20 to 25% HP, providing adequate steady hydraulic pressure. Starter time limits can be extended up to 10 minutes in flight.

  12. Airspeed ... FLY NORMAL NO-FLAP APPROACH SPEED
  13. GPWS/GND SPLR FLAP ORIDE ... ON
  14. GROUND SPOILERS ... OFF
  15. ANTI SKID ... OFF
  16. NOTE: A go-around has not been demonstrated in this configuration.

    After landing:

  17. Speed Brakes ... EXTEND SLOWLY (3 SECONDS MINIMUM)
  18. Use rudder and ailerons to counteract drift. In crosswinds, landing on the downwind side and veering slightly downwind prior to loss of aerodynamic control will aid in stopping on the runway. The PM shall monitor the applied brake pressure and advise the PF of overshoots in pressure. Do not apply more than 400 PSI maximum emergency braking pressure.

Two-Engine Loss After Takeoff

images

Did you ever wonder how low to the ground you could be after takeoff and lose all engines and still be able to land on the runway you took off from, opposite direction? Me too. I imagine the most realistic scenario is that you've got a bad load of gas to make both engines quit at the same time, that means no APU either. I've tried this in every simulator I've flown for quite some time and have come to a few conclusions:

  • You are better off flying a 90° turn followed by a 270° turn than trying to milk the airplane around on downwind for the runway you took off on, that takes too much distance and you will run out of altitude.
  • You are better off pulling 2 G's in a 60° level flight turn (60° bank) than using the standard 25° bank because that shortens the distance travelled.
  • The natural tendency in a 60° bank turn is to gain altitude. You can pitch the airplane while heavily banked. Try to maintain altitude.
  • You need to try this in the simulator because every airplane is different and some of your assumptions may be wrong. In the G450, for example, losing both engines brings you down to DC batteries which means your stabilizer is frozen. If you want flaps, you need to press the EMER STAB button to disconnect the flaps from the stab and turn the AUX pump on to get the flaps moving. Since the first 10° takes the longest time I would get those and see how the turn is progressing. If you decide on more flaps, make sure they are stopped before you touchdown or your brakes will not work.
  • You are looking for a steeper glide path than normal, since the engines are not producing any thrust. If you seem too high, apply a healthy dose of rudder and opposite aileron to slip the airplane down.

I've only tried this once in the G450 simulator and it worked, but we had too much margin built in. We failed both engines at 2,000' and ended up at 1,000' rolled out on final. (That's why I think we can do this with an engine loss at 1,000' AGL.) I've since heard from several pilots who tried it at 1,000' AGL and it worked.

References

* FSI G450 PTM, FlightSafety International Gulfstream G450 Pilot Training Manual, Volume 2, Aircraft Systems, October 2008

Gulfstream G450 Aircraft Operating Manual, Revision 35, April 30, 2013.

Gulfstream G450 Airplane Flight Manual, Revision 36, December 5, 2013

Gulfstream G450 Maintenance Manual, Revision 18, Dec 12, 2013

Gulfstream G450 Quick Reference Handbook, GAC-AC-G450-OPS-0003, Revision 34, 18 April 2013

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Revision: 20140209
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