3 ASU achieves major milestone: Cheetah 352 wing change
Date: 19 June 2006
Capt Jaques Greylingh (A/C Mech Off 3 ASU)
All scheduled maintenance on Cheetah aircraft at AFB Makhado has been converted to calendar-based instead of flying hour based due to the shortage of technical personnel and the fact that the projected scheduled maintenance could result in too large a number of aircraft due for maintenance at specific points in time. The calendar-based maintenance would therefore ensure that only two aircraft would be in the maintenance facility at 3 ASU at any given time, resulting in a more even distribution and flow of work. This would however, be challenging in the sense that the management and achieving of target dates would be crucial in preventing time overflows breaking into the next scheduled servicing and creating an obstruction to releasing aircraft to operations.
Cheetah 352 recently arrived at 3 ASU as planned for the 600 hrs service but unknowingly held some real challenges. The first part of the service consisted mainly of the dismantling of the aircraft for the NDT (non destructive testing) tasks which included the removal of both the wings and the canards. The NDT checks on the wings consist of, amongst others, X-rays of the internal structures of the wing. The NDT work team from 1 ASU arrived as scheduled and carried out all the NDT tasks on the aircraft including the X-rays. The developing of the X-rays had to be done at 1 ASU but after one week, notification was received that evidence of cracks had been identified. The work team could, however, only return to 3 ASU after three weeks due to maintenance on other aircraft types.
3 ASU along with PSSM CHET had to make a decision in order to save time and still achieve the target date. The decision was made to exchange both wings. Two brand-new wings that had never been flown before, still in their factory ‘white' paint scheme, were removed from the boxes and the servicing crew immediately started with the long and arduous task of building all the components of the old wings into the new wings. It's a little like doing a ‘heart swop' operation on a human, joining all the pieces together. The wings were sprayed at 3 ASU with the assistance of two members from 6 ASU.
It was said that a single wing change could take up to eight weeks to complete but the servicing crew managed to complete the task of changing both the wings in only six weeks. The aircraft completed its test flight on 04 June 2006 and was flown by Brig Genl D.E. Barker who commented that the aircraft rigging was perfect with hardly any trim required to counter out of balance forces.
The engine that was installed into the airframe during the service also had a story of its own to tell. The engine was identified to be phased out due to an Igniter Plug Temperature problem. 3 ASU engine repair section took the initiative to investigate whether cost effective recovery could be achieved due to the fact that a major shortage of serviceable engines was experienced during this period. After several component changes, the engine eventually passed the Igniter Plug Temperature test on the test bench and was installed into Cheetah 352 during the 600 hrs service. Both the engine and the aircraft passed the test flight first time around - truly a remarkable tribute to the skills of the technicians of 3 ASU.
The fact that the aircraft passed its test flight the first time is commendable, considering the amount of component changes involved. All the members involved with this aircraft displayed a very high level of commitment and ownership to the task at hand. Congratulations TEAM!
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