Transit checklist you ask? What transit checklist? This was deleted in 2015 and most of the information was moved to the operating manual. I say most because they failed to move the requirement to check the oil filter differential pressure indicator at least once every 14 days. There is now no published requirement to check these DPIs. In fact, Rolls-Royce says you don't need to, more about that here. So read the current AOM text below for current guidance and take a look at the deleted guidance for some background.
Engine Oil Servicing
[G450 AOM, §09-02-20, ¶2. Note.]
- BECAUSE THERE IS THE POSSIBILITY OF THE REMOTE OIL FILLER VALVE (ROFV) FAILING TO THE OPEN POSITION FOLLOWING OPERATION, IT IS IMPORTANT THAT THE CREW KNOW THE OIL CONSUMPTION RATE OF THE AIRCRAFT ENGINES.
- IF THE OIL CONSUMPTION RATE IS LESS THAN ½ (0.5) PINTS PER HOUR, OR FLIGHT IS LESS THAN SEVEN (7) HOURS DURATION, THERE ARE NO ADDITIONAL REQUIREMENTS TO THE PRESENT PROCEDURES OTHER THAN ALTERNATING ENGINE OIL SERVICING PER FLIGHT LEG IF POSSIBLE.
- IF THE OIL CONSUMPTION RATE IS GREATER THAN ½ (0.5) PINTS PER HOUR UP TO THE MAX ALLOWABLE LEVEL OF ¾ (0.75) PINTS PER HOUR, AND THE NEXT FLIGHT DURATION IS GREATER THAN SEVEN (7) HOURS, ADDITIONAL PRECAUTIONS ARE REQUIRED. TO PREVENT THE POSSIBILITY OF TAKING OFF WITH BOTH ROFV FAILED OPEN, ONLY ONE ENGINE SHOULD BE SERVICED PER LEG IF POSSIBLE. IF BOTH ENGINES REQUIRE OIL SERVICING, THEN A GROUND IDLE RUN OF THE LEFT ENGINE IS REQUIRED TO CONFIRM THE ROFV IS CLOSED. AN OPEN ROFV WOULD BE EVIDENCED BY OIL LOSS OVERBOARD THROUGH THE OVERFLOW PORT ON THE BOTTOM OF THE ENGINE COWL. TO CONFIRM THE RIGHT ENGINE ROFV IS CLOSED WILL REQUIRE THE ENGINE TO BE RUN AT 57% N1.
This entire page was deleted in 2015.
Figure: Transit Check, from G450 Quick Reference Handbook pg. NF-5/6.
This comes from an internal memorandum at Rolls-Royce:
Regarding checking the DPIs, the G450 AOM Section 2A Production Aircraft Systems 2A-79-10 2. F. Oil Filter Assembly, states “If debris collects within the filter restricting oil flow through the filter, a pressure differential will be detected by the switch. If the pressure differential reaches approximately eighteen (18) psi, the switch will indicate to the EEC an impending blockage of the filter. At approximately thirty (30±3) psi differential the oil will bypass the filter and a mechanical “pop-up” indicator will activate signaling the bypass.”. When the EEC gets the 18 psi oil pressure differential signal, the EEC will generate an ENGINE MAINTENANCE, L-R amber CAS messages which would drive maintenance to check the fault codes and take the appropriate troubleshooting/maintenance actions thus negating the need for DPI check in the QRH Postflight check since it would be annunciated in the cockpit prior to the DPI popping up at a thirty (30±3) psi differential.
Even though the oil system is designed to give ample caution of a potential oil filter bypass, there is certainly no harm in checking the DPIs when servicing the oil. If one should happen to find a DPI “popped” which was not preceded by an amber ENGINE MAINTENANCE, L-R CAS message, they should contact their Gulfstream or Rolls-Royce representative for further guidance.
If you are following the procedures in the AFM and AOM, you will never be directed to check the DPI and it appears that abides by Rolls-Royce guidance. As a technique, we service the oil at the end of each flight day using the system in the aft equipment bay and then we verify the oil levels at the sight glass on each engine. As long as we are there, we verify the DPI is closed. Some would argue that if we spot the DPI popped we are grounded. So be it, it is an expensive engine and I like to take care of it.
More about how to do that: G450 Powerplant Oil System.
Gulfstream G450 Aircraft Operating Manual, Revision 39, March 10, 2015.
Gulfstream G450 Quick Reference Handbook, GAC-AC-G450-OPS-0003, Revision 34, 18 April 2013
Rolls-Royce Tay Series Propulsion System Service Bulletin TAY-79-1698, Publication Ref. Ser-TayAC, Jul.14/06