Contrails
The goal of the Contrails project is to help preserve and disseminate the technical record of 20th century aerospace research, highlighting in particular the research endeavors of the Illinois Tech community.

A Factor Analysis of Selected How-Mal Codes

Report Number: AMRL TR 66-154
Author(s): William H. Pearson
Corporate Author: Aerospace Medical Research Laboratories
Laboratory: Aerospace Medical Research Laboratories
Date of Publication: 1966-12
Pages: 21
Contract: Laboratory Research - No Contract
Project: 7184
Task: 718403
AD Number: AD0649569

Abstract:
The report concerns the possibility of simplifying the Air Force's list of malfunction data-reporting codes (How-Mal Codes) given in AFM 66-1. Two complementary methods of approaching the problem, through analysis of the codes as reported, are illustrated using maintenance data from the T-37 aircraft. One analytical method involves a straightforward tabulation of the frequency-of-use of the various code words. The other method involves a mathematical technique (factor analysis) for identifying the basic 'factors' underlying the maintenance man's categorizations of malfunctions. Of 150 How-Mal code words, 43 accounted for 99% of the reports of malfunction tabulated on 180 mechanical components of the T-37 System. Ninety-five percent of the 62,387 malfunctions analyzed were accounted for by only 20 code words. The factor analysis suggests that as few as 16 code words may be sufficient to describe the 43 more common malfunctions. Further analyses are required, using these and other techniques and other systems, before specific recommendations can be made for simplifying the code through combining, reorganizing or grouping code words.

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