Short Term Storage

Gulfstream GVII

Eddie sez:

April 6, 2020. Well it has been an interesting couple of months. It seems any of us can be infected and not know it, and we risk spreading whatever it is we may or may not know we have to others. Many have decided not to fly at all until this blows over. Us? We've equipped ourselves with masks and fly at least once a week. We do have N95 masks, but The Lovely Mrs. made one for me so that is what I wore on this particular flight . . .

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Photo: Eddie's pattern flight, with face shield
Click photo for a larger image

But what if your operation decides you need to sit the airplane down for a few weeks? What should you do? Some of the older Gulfstreams have what is know as "LUMP," or the Low-Utilization Maintenance Program. We in the G500 don't have one of those, but we do have Chapter 10 of the Maintenance Manual, but nothing in there explicitly tells you what to do and it is filled with errors. The "Flight Ready Storage - Preservation" procedure (10-30-01), for example, says the airplane will be ready in 24 hours but has you preserve the engines and disconnect oxygen bottles. I am presenting the "Short Term Storage - Preservation" procedure as a good place to start.

Some Gulfstreams had you run the APU every five or seven days and if you couldn't do that, there were extra steps to take. In the G500, the "APU on Aircraft - Preservation" procedure (10-18-01) can be done up to 2 months after the last APU operation, so no worries there for short term storage.

You might look to our "older brother," the GVI, for guidance. Their maintenance manual requires the APU and engines be run every 7 days and that all electrical equipment be run for an hour. As with many things in the GVII, our requirements are much simpler.

Our manual says we can go two months without running the APU. The P&WC Engine Manual (PW800-72-00-00-00A-A) says the engine should be run at least once every 14 days.

I think if you are going to sit the airplane down for a week inside a secure hangar, the only thing you really need to do is disconnect the batteries in the aft equipment compartment and pull the eBatt circuit breakers. You might also consider purging the water system so it doesn't get stagnant. Beyond a week, you might consider going through the Short Term Storage - Preservation procedure, though I would be leery about disconnecting the oxygen bottles.

Everything here is from the references shown below, with a few comments in an alternate color.

Last revision:

2020-04-06

Securing Aircraft for an Extended Period

[AFM, §02-06-50]

NOTE

When not operating the airplane for five or more sequential days, perform this procedure to prevent battery voltage from depleting to below an acceptable level via ‘trickle’ losses. These actions are especially important when operating from a facility without adequate electrical ground power support.

  1. MAIN BATTERIES (Left and Right) . . . OFF
  2. NOTE

    Wait two minutes after securing Main Batteries before pulling the following circuit breakers.

  3. FWD EMERGENCY BATTERY CB1 (LEER) . . . PULL
  4. UPS BATTERY CB1 (REER) . . . PULL
  5. AFT EMERGENCY BATTERY CB1 (BEER) . . . PULL
  6. MED . . . Close
  7. MAIN BATTERIES (Tail Compartment) . . . Disconnect
  8. EBHA BATTERY (Tail Compartment) . . . Disconnect

Short Term Storage

[GVII-G500 Maintenance Manual, §10-30-02]

    Short term storage is defined as the condition of the aircraft not intended to be flown for a period up to 6 months. An aircraft in this condition is not necessarily considered to be flight ready. It is necessary to know where the aircraft will be parked, moored or hangared before this procedure starts. If the aircraft is to be kept on jacks, store it in a hangar. Make a checklist of tasks to be done to make the aircraft airworthy when put back into service.

    It is recommended, but not necessary, that the aircraft follow the applicable storage and inspection interval requirements when maintenance inspections or the aircraft outfitting (completion) procedure is done.

    Note that what follows comes directly from the maintenance manual but is offered only to provide you with a flavor of what is needed when sitting the airplane down for a while. If you plan on parking the airplane for an extended period, please consult the maintenance manual directly. You might want to skip a lot of these items if you are only talking about a few weeks, but notice that there are 5-day items related to the batteries, starting at step 25.

  1. If it is necessary, tow the aircraft to where it is to be stored.
  2. CAUTION

    DO NOT SET THE PARKING BRAKES DURING STORAGE. THE BRAKES CAN BECOME LOCKED AND NOT RELEASE EASILY.

  3. Park the aircraft as necessary.
  4. Open the landing gear doors.
  5. Remove the pressure from the applicable hydraulic system.
  6. Install all landing gear and landing gear door safety devices.
  7. Put the chocks forward and aft of each wheel with each pair attached together with a rope or other means which will keep them in position.
  8. CAUTION

    IF THE AIRCRAFT IS NOT MOORED AND DANGEROUS WEATHER IS NEAR (WINDS MORE THAN 30 KN), THE AIRCRAFT MUST BE MOVED TO A SAFE LOCATION.

  9. If it is necessary, moor the aircraft.
  10. Install the ground wire correctly.
  11. Install all protective plugs and covers.
  12. If it is necessary, install barrier ropes, caution signs and red streamers around the aircraft.
  13. Apply electrical power to the aircraft.
  14. Apply hydraulic power to the aircraft.
  15. On an ⟪OHPTS⟫, select the ⟪Aux⟫ Pump on as follows: Select Hyd/CPCS, Select Aux Pump to On.
    • Operate the flight controls.
    • Select the flaps to 0°.
    • On an ⟪OHPTS⟫, select the ⟪Aux⟫ Pump off as follows: Select Hyd/CPCS, Select Aux Pump to Off.
    • Remove the pressure from the applicable hydraulic system.
  16. Remove hydraulic power from the aircraft.
  17. Remove electrical power from the aircraft.
  18. Purge, drain, flush and clean the water and waste systems and other fluids from tanks, galley and lavatories.
  19. Clean and protect the aircraft interior as follows:
    • Remove rubbish such as paper, rags, etc.
    • Clean the cabin area in accordance with the outfitter requirements to remove dirt and organic material. Let the cabin air dry fully before the aircraft is put into storage.
    • Cover the flight deck and cabin equipment as necessary. Use only cloth or other porous materials. Do not use plastic film.
    • Cover but do not make airtight, all external openings to prevent entry of rodents, birds, etc.
  20. Inspect all hand fire extinguishers for weight or pressure.
  21. Shut off the crew and passenger oxygen bottles valves as follows:
    • On the OXYGEN SYSTEM panel, lift the switch guard and select the Crew/Pass switch to OFF.
    • Remove the cabin center carpet runner and carpet.
    • Remove floorboard 131JL-2.
    • Cut and discard the breakaway safety wire on the crew and passenger oxygen cylinder shut-off valves.
    • Shut off the crew and passenger oxygen cylinder shut-off valves.
  22. Visually inspect the components in wheel well areas for corrosion.
  23. If it is necessary, apply CIC to nonlanding gear electrical connectors in the wheel well.
  24. Preserve the main landing gear tires as follows:
    • If it is necessary, do the servicing of the aircraft tires for proper inflation.
    • The tires and brakes must be fully covered.
    • Put a protective cover on the nose wheel steering unit, taxi light assembly and the wheel well openings.
  25. If the aircraft is in storage 30 days or more, complete the External Baggage Door, Main Entrance Door, Main Landing Gear Door, and Nose Landing Gear Door Lubrication.
  26. Close the landing gear doors.
  27. If the aircraft is not to be in operation for 5 days or more, remove the security system battery.
  28. If the aircraft is not to be in operation for 5 days or more, disconnect these batteries as follows: Main batteries, FCS EBHA Batteries.
  29. If the aircraft is not to be in operation for 5 days or more, pull, tag and install the safety clips on the circuit breakers that follow:
    • CB1, CB2 - FCS UPS Battery - REER
    • CB1, CB2, CB3 - Forward Emergency Battery - LEER
    • CB1, CB2, CB3 - Aft Emergency Battery - REER
    NOTE

    When the main batteries are disconnected and the circuit breakers are pulled on the Forward Emergency Battery, the eMED will not operate. It will be necessary to connect the main batteries to operate the door.

  30. Remove electrical power from the aircraft.

Engine Preservation

[P&WC Engine Maintenance Manual, Engine Preservation, ¶7]

  • The best method to maintain an engine is to run it at least once in every 14 days at Ground Idle (GI) until the oil temperature reaches 70 °C (158 °F) minimum for 10 minutes. If engine ground run is not possible, engines can be left in an inactive state (stored outside or sheltered area), refer to the preservation schedule steps that follow.
  • 1 to 14 days - Engines can be left in an inactive state (stored outside or sheltered area), with no preservation protection. In wind, rain, snow and ice conditions, engine covers must be installed when the aircraft is parked to prevent windmilling, to keep out foreign objects and to prevent the formation of water/ice.
  • Between 15 and 90 days the inlet and exhaust covers must be installed and logged in the engine logbook. Beyond 90 days, there are specific preservation procedures in the manual.

Every Seven Days

The GVII doesn't have a procedure for what to do every seven days so what follows are my techniques. I've used the "Flight Ready Storage" procedure in the G650 Maintenance Manual (10-10-00) as a model, assuming we have less to do based on the clues given in our maintenance manual. We can assume, for example, we don't have to run the APU and engines every 5 days based on the fact our maintenance manual says we can go 2 months without operating the APU with no issues. I am reaching out to Pratt for something more definitive on the engines.

  • Check tire pressures
  • Ensure chocks are secure
  • Reconnect batteries
  • Reset FCS UPS, Forward EBatt, Aft EBatt circuit breakers
  • Apply external AC power
  • Charge batteries fully
  • Shut aircraft systems down
  • Disconnect batteries
  • Pull, tag and install the safety clips on the FCS UPS, Forward EBatt, Aft EBatt circuit breakers
  • Secure aircraft

See Also:

Gulfstream GVII-G500 Aircraft Maintenance Manual, Revision 4, June 28/19

Pratt & Whitney Canada Engine Maintenance Manual, PW800-A-72-00-00A-810A-1, Issue 50 -02/DEC/19, 33B1390, Engine Preservation