Sampling Procedures

NAVAIR 17-15-50.1

TM 38-301-1

T.O. 33-1-37-1

CGTO 33-1-37-1

NOTE

Samples may be taken earlier than the specified interval if adjustment to engine

sampling time is required to permit simultaneous engine sampling on multi-engine

aircraft. However, limits may not be exceeded to adjust sampling times.

Refer to the applicable scheduled maintenance or periodic inspection documents for

the specific routine sampling interval and specific sampling instructions for each

Type/Model/Series equipment being sampled.

Sampling Procedures. The success and effectiveness of the oil analysis program is dependent upon

reliable samples. A reliable sample is one, which is truly representative of the circulating fluid in the equipment

being evaluated.

When to Take Samples. Samples should be taken as soon as possible after engine/equipment

shutdown and before any fluid is added to the system. An exception to this requirement is non-aeronautical

equipment oil samples. If fluid was not added following shutdown, these samples may be taken without warming a

component to operating temperature if the equipment has been operated within the last 30 days. If not operated

within the last 30 days, the equipment must be brought to operating temperature before sampling. (Army

personnel sampling nonaeronautical equipment should refer to DA Pam 738-750 for additional oil analysis

procedural information.) If a sample must be taken from a unit after new oil has been added, e.g., if oil level is too

low to permit sampling or if laboratory requests a special sample following oil addition and prior to equipment

operation, the old and new oils must be thoroughly mixed to obtain a homogeneous mixture by operating the unit

to operating temperatures before taking the sample. In systems where system oil temperature is not an operating

characteristic, a judgment of operating time required to obtain a homogeneous mixture must be made based

upon system characteristics such as system capacity, pump volume output, reservoir capacity, etc. These

procedures are necessary since any sample taken from a system in which the fluid is not a homogeneous mixture

will not be representative of actual fluid condition and may distort the laboratory trend for the equipment and may

result in a resample request from the laboratory.

(1)

Routine Samples. Routine sampling intervals shall be as specified in appropriate service

documentation governing operation and maintenance of each Type/Model/Series equipment. Cognizant Weapon

System/Model Engineering activities establish and maintain sample interval documentation to provide effective oil

analysis coverage.

(2) Special Samples. Special samples from equipment monitored by the service oil analysis

programs will be taken in accordance with the following guidelines:

(a)

Whenever requested by the laboratory.

(b)

Whenever directed by the unit maintenance activity to investigate suspected deficiencies.

resulting from either malfunction of the oil lubricated system, or damage to the oil lubricated system from

excessive loss of engine oil, or low/fluctuating or zero oil pressure.

(d) Immediately prior to and after maintenance is performed affecting the oil lubricated system,

including the removal and replacement of an oil lubricated system component. Systems, which are sampled after

each flight, do not require samples taken prior to maintenance, provided an analysis was accomplished after the

last flight. The "after replacement" sample should be taken after ground/functional run-up or check flight.

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