What was found
SWITCH FAILED TO CLOSE AT PRESCRIBED LIMITS OF DN-41.1 DURING A 300-HOUR INSPECTION. THIS IS THE 7TH SWITCH TO FAIL IN LESS THAN 500 HOURS OF OPERATION SINCE FIRST FAILURE REPORTED ON 12-10-96. THAT FAILURE COULD HAVE PREVENTED AN ENGINE FAILURE DUE TO FUEL CONTAMINATION IF THE SWITCH WOULD HAVE WORKED PROPERLY. SUBMITTER RECOMMENDS A MANDATORY 100-HOUR INSPECTION INTERVAL. NOTE: AC NR 43-16, FUEL NOZZLE FILTER, 'NO FUEL BYPASS INDICATION'. NR 7313, PAGE 13.