TB 55-9150-200-24
CHAPTER 3
LUBE OILS AND OIL ADDITIVES
Section I. GENERAL
3-1. Servicing.
a. The lubricating oils listed herein for each aircraft component will be used as specified in the tables of this bulletin.
b. When proper servicing equipment is available, aircraft components will be serviced through an oil servicing unit.
If this equipment is not available and cans are used, these cans will be thoroughly cleaned prior to each servicing to
prevent contamination. Thoroughly agitate the oil in the can prior to adding oil to the system either at an oil change or
during routine servicing to ensure anti-foam additives are uniformly dispersed in the oil.
c. Gas turbine engine powered aircraft should be serviced with oil through a 10 micron or finer filter to remove
d. When oil servicing units are used to service reciprocating engine powered aircraft, the oil should be filtered
through a 240 micron (approximately 60 mesh) or finer, screen to remove coarse contaminants.
e. Under no circumstances will synthetic oils, MILL-7808 or MIL-L-23699, be mixed with mineral base oils MIL-L-
6082, MIL-L-22851, or MIL-L-2104. Mixing of synthetic and mineral oils is prohibited.
3-2. Approved Commercial Engine Oils.
a. When the Army standard oils specified in tables 3-1 and 3-2 are not available, the approved commercial engine
oils may be used as listed in table 3-3.
b. During long cross-country flights with destination at civilian airports, preflight planning will dictate that it is good
practice to carry a reserve of Army standard oil.
c. Table 3-4 lists lube oil by US Military specification, grade or type, DA symbol, NATO number, NSN, unit of issue
and pertinent comments.
d. Commercial oils for reciprocating aircraft engines conforming to Continental Motors Specification MHS-24
engines are listed by company and company product in table 3-5.
Section II. Turbine Engine Lube Oil.
3-3. Synthetic Oils.
WARNING
Lubricating oil, Military Specification MIL-L-7808 or MIL-L-23699, contains an additive which Is
poisonous and absorbed readily through the skin. Do not allow oil to remain on skin longer
than necessary.
CAUTION
To avoid contamination, do not use previously opened cans of lubricating oil. A new sealed
can of oil must be opened and used.
a. Turbine engines require oils which have a lower pour point, or better viscosity-temperature characteristics, and a
higher degree of resistance to oxidation or thermal decomposition than petroleum derived lubricants. MIL-L-23699 oil
and MIL-L-7808 oil are synthetic oils that meet these requirements and perform satisfactorily under conditions which are
too severe for petroleum products.
b. MIL-L-23699 oil and MIL-L-7808 are the oils used in the engines of turbine engine powered aircraft as indicated
in table 3-1. These oils are compatible and can be mixed. However, it is recommended these oils not be mixed as a
normal practice.
c. Gear and transmission lubricants and their specific application are listed in table 3-1.
3-4. Mixing Precautions.
a. Adding MIL-L-7808 oil to MlL-L-23699--oil will reduce the MIL-L-23699 oil high temperature and gear load
carrying capability to the MIL-L-7808 oil capability.
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