All aircraft fitted with Kelly Aerospace alternators P/N DOFF10300 series.
This Continuing Airworthiness Notice (CAN) advises operators of aircraft fitted with Kelly Aerospace alternators of the manufacturer maintenance requirement to retorque the alternator thru bolts at regular intervals.
This CAN is prompted by a significant number of Kelly Aerospace alternator failures at low hours time in service. Some alternators failed to come online and would not charge. The majority of these failures are attributed to engine vibration causing loss of alternator thru bolt torque due to metal wear on the case and/or stator.
This CAN alerts operators of aircraft fitted with Kelly Aerospace alternators P/N DOFF10300 series of the manufacturer maintenance instructions. When a new/rebuilt/exchange alternator is fitted, the manufacturer requires the retorque of alternator thru bolts after the initial 10 hours TIS, and thereafter at intervals of 100 hours TIS. T he CAA recommends the alternator bolts are retorqued at intervals of 50 hours TIS. The retorque interval can be extended to 100 hours TIS when it can be determined that there is no significant loss of alternator thru bolt torque at 50 hour intervals which could result in alternator failure. Remove the safety lock wire, loosen the bolts to break the torque, and determine the running torque value of each bolt. Retorque the alternator thru bolts to 30 to 35 inch pounds in addition to the running torque value. Secure all thru bolts with lock wire in accordance with an approved method.
Recently the manufacturer included a decal on the casing of the alternator specifying the above mentioned maintenance instructions.
