Managing the APS3200 life limit
Service Bulletin requests operators to replace affected parts
Lufthansa Technik is prepared to provide the necessary technical support regarding all questions concerning the APS3200. The main rotating parts of the APS3200 APU have been managed under a Life Management Plan (LMP), which called for an eventual progression to fixed life limits. Meanwhile these limits have been established and parts exceeding the limits must be replaced.
Fixed life limits for the Airbus A320 family APU
The Life Management Plan for the APS3200 main rotating parts, i.e. the load compressor impeller, the power section impeller, the first-stage turbine disk and the second-stage turbine disk, called for an on-going assessment of the parts during shop visits. APU manufacturer Pratt & Whitney Canada is now preparing to implement fixed life limits in the Engine Manual of the APS3200, the baseline auxiliary power unit (APU) for the Airbus A320 aircraft family. For the load compressor impeller and the power section impeller a limit of 50,000 cycles has been established, the corresponding number for the first-stage and second-stage turbine disk is 32,000 cycles.
Parts that exceed the limits have to be replaced
Obviously this means that there are a number of APUs operated in the field equipped with rotating parts that have accumulated cycles greater than the life limits given above. The corresponding Service Bulletin (P&WC S.B. No. 320150) therefore requests operators to replace the affected parts within a specified time frame. Parts with 15,000 APU cycles or more above the fixed life limits constitute the most urgent case. These parts must be replaced within the next 500 APU cycles or three months, whichever comes first. Further details can be found in the above mentioned Service Bulletin.