81-25-02 MCDONNELL DOUGLAS: Amendment 39-4270. Applies to McDonnell Douglas Model DC-8 series airplanes certificated in all categories. Compliance required within six months from the effective date of this AD, unless already accomplished. To assure that proper windshield heat generation is available for bird impact protection and anti-ice functions, on aircraft that have had left, center, or right windshield panels replaced since November 1, 1978, accomplish the following: \n\n\tA.\tInspect windshield panels to determine manufacturer and year of manufacture. Windshield panels may be identified by the manufacturer's logo "PPG" or "LOF" in large capital letters with part number specification, and serial number adjacent to logo. These are located at the top panel on the left and right-hand windshield panels, and at the bottom or top of the center windshield panel. \n\n\t\t1.\tPanels manufactured by Libbey Owens Ford (LOF), no further action is required. \n\n\t\t2.\tPanels manufactured byPPG: \n\n\t\t\ta.\tDetermine the year of manufacture, which is contained in the serial number. Serial number samples are shown below: \n\n\t\t\t\t8-H-11-20-220-315 (first digit indicates year of manufacture, 1978; third digit indicates month, November) \n\n\t\t\t\t9-H-5-21-315-373 (first digit indicates year of manufacture, 1979; third digit indicates month, May) \n\n\t\t\t\tO-H-4-6-219-215 (first digit indicates year of manufacture, 1980; third digit indicates month, April) \n\n\t\t\t\t1-H-3-6-317-212 (first digit indicates year of manufacture, 1981; third digit indicates month, March) \n\n\t\t\tb.\tWindshield panels with an October 1978 or prior manufacturing date coded or January 1981 or subsequent manufacturing date coded, no further action is required. \n\n\t\t\tc.\tAircraft with less than 200 flight hours on replacement panel(s), accomplish the following resistance check of PPG November 1, 1978, through December 31, 1980, date coded windshield panels: \n\n\t\t\t\t(1)\tDC-8-60 series windshield resistance check:(a)\tOpen anti-ice windshield heat right, center, left, and right, center, left anti-fog circuit breakers on EPG circuit breaker panel. \n\n\t\t\t\t\t(b)\tDisconnect windshield electrical conductor from receptacle on left, right, and center windshield panels. \n\n\t\t\t\t\t(c)\tUsing an ohmmeter check resistance between Terminal L and P at the receptacle on left (right) windshield panel. Resistance should be 61.2-82.8 ohms. \n\n\t\t\t\t\t(d)\tUsing an ohmmeter check resistance between Terminals E and G at receptacle on center windshield panel. Resistance should be 67.5-92.5 ohms. \n\n\t\t\t\t\t(e)\tReconnect the windshield electrical conductor to receptacle on windshields and close the power system circuit breakers. \n\n\t\t\t\t(2)\tDC-8-50 series and prior windshield resistance check: \n\n\t\t\t\t\t(a)\tOpen the outer pane windshield heat circuit breakers for the left, right, and center windshields on the heat, vent, and ice protection (AC bus) circuit breaker panel. \n\n\t\t\t\t\t(b)\tRemove access door No. 623 onthe first officer's console and electrical power center. \n\n\t\t\t\t\t(c)\tDisconnect the conductor connected to transformer Terminal X, Y, or Z on three tap transformer or V, W, X, Y or Z on five tap transformer of windshield to be tested. \n\n\t\t\t\t\t(d)\tUsing an ohmmeter, check resistance between transformer Terminal 1 and the conductor disconnected from the transformer. Resistance should be 81.6 to 110.4 ohms for left (right) windshield. \n\n\t\t\t\t\t(e)\tUsing an ohmmeter, check the resistance between transformer Terminal 1 and the conductor disconnected from the transformer. Resistance should be 96 to 130 ohms for the center windshield. \n\n\t\t\t\t\t(f)\tReconnect conductors to terminals. \n\n\t\t\t\t(3)\tIf windshield resistance is: \n\n\t\t\t\t\t(a)\tWithin tolerance on all three panels, aircraft may be continued in service and panels must be respectively inspected at 50-hour intervals until the accumulation of 200 flight hours. \n\n\t\t\t\t\t(b)\tWithin tolerance after the accumulation of 200 flight hours, nofurther action is required. \n\n\t\t\t\t(4)\tIf resistance is out of tolerance on one or more of the three windshield panels: \n\n\t\t\t\t\t(a)\tFor DC-8-60 series center panel out of tolerance install the following placard in full view of pilot: "Do Not Exceed 260 kts IAS Below 10,000 Feet Altitude." \n\n\t\t\t\t\t(b)\tFor DC-8-60 series with only side panel(s) out of tolerance, install the following placard in full view of the pilot: "Do Not Exceed 285 kts IAS Below 10,000 Feet Altitude." \n\n\t\t\t\t\t(c)\tFor DC-8-60 series, if left (right) windshield panel(s) resistance is 82.9 to 130 ohms and/or center windshield panel resistance is 92.6 to 130 ohms, full anti-ice capability is available. Panels must be repetitively inspected at 50-hour intervals, until the accumulation of 200 flight hours, to ascertain that the resistance remains at or below 130 ohms. After the accumulation of 200 flight hours, the repetitive inspection interval can be extended to 1500 flight hours. \n\n\t\t\t\t\t(d)\tFor DC-8-50 series and prior with resistance out of tolerance on one or more of the three windshield panels, install the following placard in full view of the pilot: "Do Not Exceed 245 kts IAS Below 10,000 Feet Altitude." \n\n\t\t\t\t\t(e)\tIf windshield heat is unavailable for ice protection, install the following placard in full view of the pilot: "Windshield Heat Inoperative." In certain cases, the rain removal system can be used to de-ice or anti-ice windshields. See procedures in the Airplane Flight Manual. \n\n\t\t\t\t\t(f)\tThe above restrictions can be removed when the out-of-tolerance panel(s) is/are replaced with panel(s) manufactured by LOF or any PPG manufactured panel(s) with a date code other than November 1, 1978, through December 31, 1980. \n\n\t\t\td.\tFor November 1, 1978, through December 31, 1980, date coded windshield panels which have over 200 flight hours, accomplish the resistance check per paragraph c(1) or c(2), as applicable. \n\n\t\t\t\t(1)\tIf windshield resistance is within tolerance on panels,no further action is required. \n\n\t\t\t\t(2)\tIf resistance is out of tolerance on any of the three panels, accomplish the instructions as outlined under paragraph c(4). \n\n\tB.\tAlternative inspections, repairs, or other action to be accomplished on or after the effective date of this AD which provide an equivalent level of safety, may be used when approved by the Chief, Los Angeles Area Aircraft Certification Office, FAA Northwest Mountain Region. \n\n\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD. \n\n\tThis amendment becomes effective January 4, 1982.