# AC 91-60: The Continued Airworthiness of Older Airplanes - Type: Advisory circular (guidance, not mandatory unless a rule or AD requires it) - Status: Historical - Approved: June 13, 1983 - Family: AC 91-60 - Pages: 4 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/62DB373E4BCBA3C7862569D900744CAA.0001 - Page: https://openairdocs.org/ac/91-60 ## Versions - AC 91-60 (Historical), approved Jun 13, 1983 ## Text ### Page 1 Advisory I’ J U.S. Department of Transportation FederaiAv/Qtion Mministmtion b Circular Subject: ‘IHE OONTINUED AIRWXTHINESS OF OLDER AIRPLANES Date: VW83 AC No: 9b60 Initiated by: AM-340 c-w: 1 PURPOSE l This advisory circular (AC) provides information and reccmmndations to manufacturers and airplane m&operators for the developmnt and use of programs to assure the continued airworthiness of older airplanes not covered under AC 91-56, Supplemntal Structural Inspection Program for Large Transport Category Airplanes. 2 l BACKGROUND l Airplanes are designed and built to provide mny years of service. For the airplarw3 to remain airworthy and safe to aperate for a long ' inservice life, it should be operated in accordance with the ret-ndations of the manufacturer and cared for with sound inspection and mintenanoe practices, . . , . _ :. r* a. Service experience has revealed that an aging aiqlane needs mre care and special attention during the maintenance processes and, at tirres, requires more frequent inspection of structural components for damage due to environmntal deterioration, accidental damage, and fatigue. Typical areas requiring mre frequent inspect ion, and key to continuing the useful life of an airplane are structural points such as: (1) Wing spar capstrips, with particular attention to the spar lower capstrips. (2) Wing attach points, both on the wing and on the fuselage. (3) Wing fuselage carry-through structure. (4) Wing upper and lower covers between spars. (5) Pressurized structures, especially around doors, windows, windshields and other cutouts on pressurized airplanes. (6) Horizontal tail spars and spar capstrips. (7) Horizontal tail spar attachmmts and fuselage attachrrrents. (8) Horizontal tail fuselage carry-through structure. (9) krtical tail spars and spar capstrips. (10) ertical tail spar attachments and fuselage attachmmts. ### Page 2 6113183 * - AC %60 Lifting surfaces. Control surfaces and their respective hinge points. (U ) Control surface balance weight attachments. (14) Control system attach points at the various qkrol s&a-s, (15) Tab hinges. (16) Tab actuators. (17) -Main landing gear attach points where landing gear loads feed into primary wing and/or fuselage structure. (18) Structure and flooring especially in the vicinity of lavatory and galley areas and areas of overboard drains and vents. (19) Structural and flooring area attactints in cabin and cockpit and at seat and equiprrrent attachments. / 4 ” c’ b safety if In addition to the key items outlined above which are important to flight, there are other areas that should receive special attention. Typical areas are: , (1 (2 . - (3 (4 (5 (6 (7 structure 0 , * -. . Engine munts. Repeller blades. Door latching mxhanisms on pressurized airplanes. Windshields and windows on pressurized airplanes. Landing gear shimy dampers. Main and nose gear supporting structure. Cowling, fairing, and fillet attacbnts and supporting (8) Materials used in aircraft oanpartmnt interiors (including finishes or decorative surfaces applied to the materials) to assure they ha= not deteriorated due to aging, cleaning or other causes that would increase their flamability over what it tias when they wzre new. 3 l OONTINUEDAIRWRTHINESS. To provide for a safe operation, a program called “continued airworthiness” should be developed by the manufacturer and used by uwners/&erators where virtually every oarponent -rising an airplane is . involved in w form of preservation, inspection, maintenance, prewntive maintenance, overhaul, repair, and/or replacement activity. Par 2 ### Page 3 , a. Safety of -ration through continued airworthiness demands increasing vigilance as an airplane ages. Airplane structural materials do have finite lives? and the extent of these is affected w age I operational environment, and operational experience which the material endures in day-to-day usage of the airplane. e b 0 Maintenance information needs to be continually updated. @en cmnunication should exist with the mmer/operator advising the mnufacturer as soon as a new situation arises, and the manufacturer responding with solid help. Such cmnication and cooperation will facilitate the maintenance of an entim fleet of airplanes in a continuously airworthy condition. 4 . M?WUF'ACTURERS' PARTICIPATION. The frmwork for continued airworthiness of airplanes is dependent upon the care and thought designed into the airplane at its inazption and reflected in the type design. Following type certification, the establismnt of, and adherence to, thorough maintenance procedures is required. Thus the mnufacturer should prepare and distribute mcanrrrendations on the rreed for increased inspection vigilance for those older (geriatric) airplanes which may not have a well-defined program for continued airworthiness, and which include areas of special consideration as are listed in paragraph 2(a) ati (b) of this AC. This infomtion should be available in clear, concise language to those who need it. Smtimes, especially for complex airplanes, it may be necessary to provide specific training in the proper xnaintenanw of the airplane and its system. These activities should be developed by the manufacturer based upon its familiarity with the designand function of the airplanes. 5 IMPLEMENTATION BY CWNERS/OPERAXRS. Vigilance is the price of safety and, eien though the manufacturers have done their best to anticipate all the maintenance required to provide for continued airworthiness, aging airplanes demand ever increasing care. Because of this the final care rests primarily with the -r/operator who should: a. Follm the manufacturer’s rmommded maintenance and inspection prooedums. b Recognize that mrrosion or damage to structure fat&e life and be on the lookout for these conditions. can drastically shorten c. Be alert to the possibility that the airplane is mt being used in a manner significantly different frcan the originally intended mission profile. W altitude operation, such as pipeline patrol, sightseeing, or training operations, will subject the airplanes to mm fatigue damage than high altitude cruise l d Comply with applicable Airworthiness Directives, and review possible modif ications available fran the mnufacturer. Structural irrprovernents are usually directed to lowering working stresses, and the sooner they are mde, the better they are to slow the onset of currrulative damage to the original structure l Par 3 3 ### Page 4 AC 91-60 6/13/.83 e. Becorn interested in the fatigue program on prospective r%w airplanes, including a clear understanding of the Elated inspection program remnded by the manufacturer, and make axtain all significant areas of the airplane’s structure are treated in the airplane’s inspection program. 3 h A, Pontecorvo A Director of Airworthiness Par 5 --- From OpenAirDocs.org, an independent open copy of FAA data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.