Spectrometric Limitations.

NAVAIR 17-15-50.1

TM 38-301-1

T.O. 33-1-37-1

CGTO 33-1-37-1

(2)

The D-3 standard, has an assigned shelf/service life of 12 months with no extensions authorized.

Designation

Elements

Concentration

Shelf Life

D-19

None

*30 months

D-3

B, Mo, Zn

100

*12 months

D-12

Fe, Al, Cr, Cu, Pb, Na,

**5, 10, 30,

*30 months

Mg, Ni, Si, Ag, Sn, Ti

50,100, 300

Shelf/service life assigned is finite with no extensions allowed. Standards reaching service life shall be

locally disposed of in accordance with applicable service regulations.

The 5 PPM concentration is not applicable to AOAP laboratories.

(3) Stocking Standards. Local supply departments are prohibited from maintaining standards in stock

due to shelf life control requirements. Standards ordered through local supply activities will be forwarded from the

stocking point. Therefore, it is recommended that laboratories frequently inventory standards on hand and order

replacement stock 30 to 45 days in advance of anticipated requirements.

2-6. Spectrometric Limitations. The spectrometric/spectrophotometric fluid analysis methods detect only small

particles and are effective in detecting those failures characterized by an abnormal increase in the wear-metal

content of the lubricating fluid. This is particularly true of failures that proceed at a rate slow enough to permit

detection by the laboratory. Examples of both detectable and undetectable failures are listed below.

Detectable Failures.

(1)

The following are good indicators of impending engine/component failure:

(a) A slow, progressive wear-metal concentration buildup above established abnormal criteria.

(b) A series of rapid wear-metal concentration increases occurring below established abnormal

criteria.

(2)

Typical sources of wear found in detectable failures.

(a) Jet/Turbine Engines. Worn bearings (balls, cages, races), bearing seals and retainers,

bearing housings, constant speed drives, oil pump gears, and gearbox castings.

(b) Reciprocating/Internal Combustion Engines. Worn bearings, crankshafts, cylinder walls, oil

pump gears, piston pin bushings, piston rings, push rods, rocker arms, valve guides, and valve springs.

Undetectable Failures.

(1) Catastrophic failures. Sudden failures not preceded by characteristic wear-metal generation,

such as fatigue failure, cannot be detected by spectrometric oil analysis techniques now in use.

(2) Failures with no wear-metal indications. Equipment failure may occur when metal particles too

large to be detected by spectrometric methods are generated without the accompanying normal wear-metal

generation pattern that oil analysis is designed to detect.

2-3