In-Flight Loss of Oil Pressure

In-flight loss of oil pressure in a Pratt Whitney JD15-1, 1A, 1B, 4, 4B, 4D engine can turn into a very serious issue.
Should a pilot encounter loss of oil pressure in-flight, as long as it is not below 35 PSI, (Annunciator Warning Light and Master Caution Warning Light comes ON), a checklist should be consulted immediately and proper action taken, however should the oil pressure drop to 35 psi or below, engine should be shut down immediately. This is a memory item! Remember those?
Once you land and you report this incident to the maintenance facility, expect the following question;

  • How long did the engine run with oil pressure below 35 psi prior to shutdown?

Depending on the answer, the maintenance facility will refer to the attached chart to determine the proper course of action.
See attached Engine Turbine Inspection Guide
The JD15D P&W engines, once running oil pressure stays usually always very stable in the green zone, unlike a piston which oil pressure fluctuates during power settings changes, especially during low idle which in most cases oil pressure can drop in the yellow caution zone.
In my experience should a pilot observe oil pressure into the yellow area after start up or during taxi, this is usually a good indication oil quantity is low. Should this be noticed, oil should be checked immediately to ascertain if quantity is low due to normal oil consumption or not.
Test your knowledge with the below two-question exam. Need help or get the wrong answers? No worries! Contact Florida Flight Center for a refresher and always know what to do in the event of an in-flight loss of oil pressure.

1.  What is normal oil consumption on the JT15D engines?

a.  One quart every 4 hours measured over a 10-hour period
b.  Two quarts within a 4 hour period
c.  Two quarts within a 10 hour period

2.  When should oil level be best checked on the JT15D engines?

a.  Before start
b.  Within 10 minutes of shutdown
c.  Both a & c

1. The maximum allowable oil consumption is 1 quart every 4 hours measured over a 10-hour period (a). 2. The oil level should be checked as a post flight item. For a valid indication, the check should be done approximately 10 minutes after engine shutdown (b).

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