DATE . 4/7/76 Li -” ” ‘ADVISORY - L,j’{ CIRCULAR DEPARTMENT F TRANSPORTATION FEDERAL VIATION DMINISTRATION RECIPROCATING ENGINE OVERHAUL TERMINOLOGY AND SUBJECT: STANDARDS 1. PURPOSE. This advisory circular discusses engin e over- haul terminology and standards that are being used in the aviation industr y : a. To inform the owner o r operator of the varie ty of terms used to describ e types of reciproc ating engine overhaul. b. To cla rify the standards used by the in- dustry during reciproc ating engine over- haul. c. To review the Federal Aviation Regulati ons (FAR ) regarding engine records and stand- ards. 2. REFERENCES. FAR 43, Sectio ns 43.9, 43.13 (a), and 43.13 (b) ; FAR 91, Sectio ns 91.173 a nd 91.175 . 3. BACKGROUND. In the maintenance of aircraft engines, terms used throughou t the aviation industry. ThC standard to which an engine is overhauled usual ly depends on the terms used by the person who is performing the engine overhaul. These terms are famili ar to the aviation community, but their sp ecif ic meanings are not full y under- stood. This could result in similar engines being overhauled to different tolerances. We belicvc that through the discussi on th at follows , owners or operators and engine overhaul faci liti es wil l have a better understanding of the terms and standards relating to those terms. 4. DISCUSSION. a. The selection of an overhaul facility by the avera ge aircraft owner is usually deter- mined by the cost quoted by the eng ine overhauler. Engine overhauls can lx ac- complished to a varie ty of standards. They can also be accomplis hed by many different facil ities , ranging from engine manufactur- ers, large repair stations, or individual powerplant mechanics . The select ion of an overhaul facility can and does, in most cases, determine the standards that, are used during overhaul. The FAR requirement in Section 43.13(a) is that the person perform- ing the overhaul shal l use methods, tech- niques, and practi ces that are acceptable to the Administr ator. In most cases, the standards that are outlined in the Engine, Manufacturer Overhaul hfanuals are stand- ards acceptable to the Administr ator. b. These manuals cle arly st,ipulate the work that must bc accomplis hed during engine overhauls and out,linc limits and tolerances used during t,hc inspecti ons. There is no diction ary that provides a commonly ac- cepted standard definition ‘of all the terms used in the aviation industry . The terms Initiated by: AFS-83 0
