93-11-01 MCDONNELL DOUGLAS: Amendment 39-8593. Docket 92-NM-48-AD. Supersedes AD 92-03-01, Amendment 39-8155. \n\n\tApplicability: Model DC-9-11, -12, -13, -14, -15, and -15F series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent degradation of lift due to ice accumulation on the wing leading edge, accomplish the following: \n\n\t(a)\tExcept as provided by paragraph (b) of this AD, within 10 days after January 17, 1992 (the effective date of AD 92-03-01, Amendment 39-8155), revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to include the following. This may be accomplished by inserting a copy of this AD in the AFM. \n\n\t"Wing De-icing Prior to Takeoff \n\nCAUTION \n\nThe Model DC-9-10 series airplane has a wing design with no leading edge high lift devices, such as slats. Wings without leading edge devices are particularly susceptible to loss of lift due to wing icing. Minute amounts of ice or other contamination (equivalent to medium grit sandpaper) on the leading edges or wing upper surfaces can cause a significant reduction in the stall angle-of-attack. This can increase the stall speed up to 30 knots. The increased stall speed can be well above the stall warning (stick shaker) activation speed. (END OF CAUTIONARY NOTE) \n\nThe leading edge and upper wing surfaces must be physically checked for ice/frost when the airplane has been exposed to conditions conducive to ice/frost formation. Takeoff may not be initiated unless the flight crew verifies that a visual check and a physical (hands-on) check of the leading edge and upper wing surfaces have been accomplished, and that the wing is clear of ice/frost/snow accumulation. Icing/frost/snow conditions exist when the Outside Air Temperature (OAT) is below 6 degrees C (42 degrees F); and either the difference between the dew point temperature and OAT is less than 3 degrees C (5 degrees F), or visible moisture (rain, drizzle, sleet, snow, fog, etc.) is present.\n\n NOTE \n\nThis limitation does not relieve the requirement that aircraft surfaces are free of ice, frost, and snow accumulation as required by Federal Aviation Regulations Sections 91.527 and 121.629. (END OF NOTE)" \n\n\t(b)\tParagraph (a) of this AD does not apply to any airplane that is both operated in accordance with Federal Aviation Regulation (FAR) 121.629(c), Amendment 121-231, and modified in accordance with either paragraph (c)(1) or (c)(2) of this AD. \n\n\t(c)\tWithin 9 months after the effective date of this amendment, accomplish the procedures specified in either paragraph (c)(1) or (c)(2) of this AD: \n\n\t\t(1)\tModify the bleed air anti-ice system so that it can operate on the ground to prevent ice reformation on the wing leading edges after ground equipment has been utilized to properly deice the airplane, and to minimize the effect of undetected ice/frost/snow contamination. Accomplish the modification inaccordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Or \n\n\t\t(2)\tInstall a supplemental on-ground wing leading edge ice protection system in accordance with McDonnell Douglas DC-9 Service Bulletin 30-65, dated October 8, 1992. \n\n\t(d)\tUpon the accomplishment of the modification required by paragraph (c) of this AD, revise the AFM in accordance with either paragraph (d)(1) or (d)(2) of this AD: \n\n\t\t(1)\tRevise the Limitations section to include appropriate operating procedures relative to operation of the modification required by paragraph (c) of this AD. These operating procedures must be approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Or \n\n\t\t(2)\tRevise the Limitations section to include the following operating procedures relative to the operation of the modification required by paragraph (c) of this AD. This may be accomplished by inserting a copy of this AD in the AFM. \n\n\t"Use of Bleed Air Anti-Ice System\n\nCAUTION \n\nThe Model DC-9-10 series airplane has a wing design with no leading edge high lift devices, such as slats. Wings without leading edge devices are particularly susceptible to loss of lift due to wing icing. Minute amounts of ice or other contamination (equivalent to medium grit sandpaper) on the leading edges or wing upper surfaces can cause a significant reduction in the stall angle-of-attack. This can increase the stall speed up to 30 knots. The increased stall speed can be well above the stall warning (stick shaker) activation speed. (END OF CAUTIONARY NOTE) \n\nThe bleed air anti-ice system must be on whenever icing conditions exist or are anticipated, when on the ground, until immediately prior to commencement of takeoff roll." \n\n\t(e)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO. \n\n\tNOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\n\t(f)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(g)\tThe installation of a supplemental on-ground wing leading edge ice protection system shall be done in accordance with McDonnell Douglas DC-9 Service Bulletin 30-65, dated October 8, 1992. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51, as of July 22, 1993 (58 FR 33898, June 22, 1993). Copies maybe obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, California 90846-1771, Attention: Business Unit Manager, Technical Administrative Support, Dept. L51, Mail Code 2-98. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office (ACO), 3229 East Spring Street, Long Beach, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(h)\tThis amendment becomes effective on July 22, 1993.