What was found
FIRST PUMP REPLACED APPEARED TO HAVE OVER 800 HRS IN SERVICE. REPLACED WITH NEW AIRBORNE PUMP 10/95. IT LASTED 35.9 HRS. REPLACED AGAIN 12/95 LASTED 31.9 HRS. SYSTEM CHECKED WITH AIRBORNE 343 TEST KIT. PUMP LASTED 16.0 HRS. REPLACED AND SYSTEM CHECKED, LASTED 23.3 HRS. LAST 3 PUMPS SENT DIRECTLY TO AIRBORNE FOR ANALYSIS. ALL PUMPS WARRANTIED, BUT HAVE BEEN UNABLE TO DETERMINE A CAUSE FOR CONTINUED FAILURES. HAVE DISCUSSED PROBLEM WITH BEECH, CONTINENTAL, AND AIRBORNE. AT THIS POINT, SUSPECT FAULTY PUMPS.