PRINCIPLES OF NAVAL ENGINEERING 



NATIONAL BUREAU OF STANDARDS 



NAVY STANDARDS LABORATORIES — TYPE I 



EASTERN SL, WASHINGTON, D.C. 

 WESTERN SL, SAN DIEGO, CALIF. 



NAVY STANDARDS LABOR ATORIES— TYPE 3L 

 (SHORE BASED) 



170.49 



Figure 7-40. — Navy Calibration Program Structure. 



Requirements List (NAVAIR 17-35MTL-1 NAV- 

 SHIPS) is available and used to find the following 

 information relating to a particular instrument: 



(1) Instrument Calibration Recall Intervals 



(2) Applicable Procedure Numbers 



(3) Related Technical Numbers 



(Note: The Metrology Requirements 

 where you can find calibration cycles.) 



List is 



Cross-checks involve the comparison of two 

 or more instruments of equal or near equal ac- 

 curacy for the sole purpose of determining if the 

 values of any of the instruments have shifted 

 significantly. The cross-check is used as an 

 interim measure until a standard or instrument 

 of sufficiently high accuracy can be used to 

 calibrate or qualify an instrument. 



Incidental repair is the term used to describe 

 those repairs found necessary during the cali- 

 bration of an operable equipment to bring it 

 within its specified tolerances. Incidental repair 

 includes the replacement of parts which have 

 changed value sufficiently to prevent calibration 

 but not enough to render the equipment inopera- 

 tive. Incidental repair is normally performed 

 in the laboratories in conjunction with the cali- 

 bration of test equipment or standards. 



Laboratory standard is the term used to 

 identify a laboratory-type device that is used to 

 maintain the continuity of values in units of 

 measurement by periodic comparison with 

 standards of Navy laboratories or with standards 

 maintained by the National Bureau of Standards. 

 A laboratory standard is used to calibrate a 

 standard of lesser accuracy. 



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