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;
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.
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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.
Questions:
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
ANSWERS:
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).
