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You have three modes: crossbleed, APU assisted, and windmill. So which?

  1. Crossbleed, unless you are in icing conditions. You can do this from VREF to VMO all the way to 30,000 feet. You can't do this in icing conditions because you need the good engine's bleed air to heat the wings.
  2. APU assisted. The only reasons I can think of that will necesitate this option is if you have both engines failed, the operating engine's bleed air system has failed, or the operating engine cannot put out 22 psi bleed air pressure (which is unlikely). The start envelope is the same as with a crossbleed start.
  3. Windmill. You will need to do this if the operating engine's bleed is needed for wing anti ice or if the failed engine's starter air valve is stuck closed. The envelope is much more narrow: 250 KCAS to VMO and no higher than 16,500 feet.

images

Photo: G50 Powerplant, Airstart envelope, PAS, p. 14-14

Click photo for a larger image

AFM Procedure

[AFM, §04-08-20]

CAUTION

DURING AIRSTARTS, MAX TGT FOR AIRSTART IS 975°C.

THE ENGINE MAY BEGIN A WINDMILL START WHEN THE FUEL CONTROL IS SET TO RUN INDEPENDENT OF AIRCRAFT ALTITUDE AND AIRSPEED. THE AIRSTART WILL TRANSITION TO AN ASSISTED START WHEN THE START SWITCH IS PRESSED. DURING AN ASSISTED AIRSTART, ALLOW NO MORE THAN 5 SECONDS BETWEEN FUEL CONTROL

Corrective Action

  1. Secondary Engine 1/6 Synoptic . . . Select

  2. Affected Engine . . . Confirm

  3. Throttle (Affected Engine) . . . Verify IDLE

  4. NOTE

    Do not attempt an airstart if an Eng Fail (warning) CAS message was displayed.

  5. FUEL CONTROL (Affected Engine) . . . Verify OFF

  6. FUEL PUMPS (All Operable) . . . Verify On

  7. Altitude . . . At or below 30,000 feet

  8. ENG BLEED AIR (Affected Engine) . . . OFF

  9. ECS Pack (Affected Engine) . . . OFF

  10. If WAI use is required or starter air valve failed closed:
    1. Refer to 04-08-30, Windmill Airstart.

  11. WAI . . . Verify OFF

  12. If Engine Bleed Air is not available:

    1. Go to Step 15.

  13. FUEL CONTROL (Affected Engine) . . . RUN

  14. ENG START . . . PRESS

  15. FUEL FLOW / TGT / RPM . . . Monitor

    1. If start successful: Go to Step 23.

    2. If start not successful: Go to Step 22.

  16. APU MASTER . . . ON

  17. NOTE

    The APU READY light may not illuminate if the APU oil temperature is below the minimum required for start. The APU start is not inhibited and may be attempted.

  18. APU . . . START

  19. NOTE

    Cabin altitude will climb with both Bleed Air Systems secured and should reach 8000 feet in approximately 3-4 minutes.

  20. ENG BLEED AIR (Operating Engine) . . . OFF

  21. ECS Pack (Operating Engine) . . . OFF

  22. FUEL CONTROL (Affected Engine) . . . RUN

  23. ENG START . . . PRESS

  24. FUEL FLOW / TGT / RPM . . . Monitor

    1. If start successful: Go to Step 23.

  25. If start not successful:

    1. FUEL CONTROL (Affected Engine) . . . OFF

    2. If another restart will be attempted:

    3. (1) Assisted Airstart . . . Conduct at lower altitude and / or higher speed

    4. If another restart will not be attempted:

    5. (1) Airplane . . . Land as soon as possible

      (2) ENG BLEED AIR (Operating Engine) . . . ON

      (3) Isolation Valve . . . Open (Depressed)

      (4) ECS PACK (Left and Right) . . . ON

      (5) Refer to 02-08-60, Fuel Balancing in Flight.

      (6) Refer to 04-08-30, One Engine Inoperative Landing Procedure.

  26. If the engine restarts:

    1. Airplane . . . Land at nearest suitable airport

    2. ENG BLEED AIR (Affected Engine) . . . Leave off for remainder of flight

    3. ENG BLEED AIR (Operating Engine) . . . ON

    4. Isolation Valve Open . . . (Depressed)

    5. ECS Packs (Left and Right) . . . ON

    6. TCAS . . . TA/RA

    7. If WAI is required:

    8. (1) Isolation Valve . . . Closed

      (2) ECS Pack (Affected Engine) . . . Off

      CAUTION

      WAI MUST BE ACTIVATED AND REACH AN OPERATING TEMPERATURE GREATER THAN 100°F PRIOR TO ENTRY INTO ICING CONDITIONS.

      (3) WAI . . . ON

      (4) ECS System . . . Monitor

      (5) Refer to 02-08-60, Fuel Balancing in Flight.

    9. If hydraulic pressure fails to indicate after restart:

    10. NOTE

      Hydraulic pressurization indications may be delayed between 30 seconds and 5.5 minutes after a successful airstart. The procedures below will minimize the delay.

      (1) Throttle (Affected Engine) . . . Increase above Idle

      (2) Altitude . . . Descend below 15,000 feet

References

Gulfstream GVII-G500 Airplane Flight Manual, Revision 3, July 16, 2019

Revision: 20190731
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