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Engine Oil Consumption Logs

September 2014

Monitoring your engine oil consumption is a very important step in maintaining a healthy engine. A simple log that both flight crew and maintenance personnel have access to would suffice, as well as proper education as to when to service the oil.

Oil Consumption Log

With the aircraft away from home, the adding of oil isn't always communicated to maintenance. At the same time, flight crews may need to answer what the oil consumption is if they have an issue.

Troubleshooting oil consumption is not always easy because some leaks are internal and would never be seen. When asked what the actual consumption is, this simple log would be of great benefit rather than an answer of "one engine seems to take more oil than the other."

When To Service The Oil

What we are seeing an increase in is over-servicing of the oil system. This might be because of some common misconceptions.

Common misconceptions:

  1. Service the oil while the engine is cold or has been sitting idle.
  2. Always keep the oil level at the full mark.

For many engine models, both statements would be incorrect.

Servicing the oil within a specified amount of time after shutdown is the preferred time. Different engine models have different times listed in their maintenance manuals, but allowing the oil to stabilize after shutdown is the key and this time could range from 15 - 45 minutes.  

Servicing the oil to the proper level in many cases will show a decrease in oil consumption. Each engine has its own personality. For example, one engine may show no significant consumption if maintained at half-a-quart low while the other engine may be maintained at three-quarters of a quart low.

Some engine OEMs publish information on how to figure out how to get to that optimum oil level.

In short, flight crews and maintenance personnel need to come together and discuss how and when to properly service the oil, creating a means to log the addition of oil and discussing the responsibilities of ground personnel service when the aircraft is away from home.