Airworthiness Directive · Amendment 39-11890 · Aerospatiale Model ATR42 and ATR72 Series Airplanes
Aerospatiale Model ATR42 and ATR72 Series Airplanes
The following airplanes, certificated in any category:
—Model ATR42 series airplanes, excluding those modified in accordance with Aerospatiale Matra ATR Modifications 4993, 4998, and 5008
—Model ATR72 series airplanes, excluding those modified in accordance with Aerospatiale Matra ATR Modifications 4994, 4997, and 5008
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD), applicable to all Aerospatiale Model ATR42 and ATR72 series airplanes, that requires modification of the alerting capability of the anti-icing advisory system to improve crew awareness of icing conditions, replacement of the median wing de-icing boots with extended de-icing boots, and installation of de-icing boots on the metallic wing leading edge. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to reduce the degradation of lift and drag characteristics in prolonged severe icing exposure, which could result in loss of lift and consequent reduced controllability of the airplane.
To reduce the degradation of lift and drag characteristics in prolonged severe icing exposure, which could result in loss of lift and consequent reduced controllability of the airplane, accomplish the following:
(a) Within 30 months after the effective date of this AD, replace the median wing de-icing boots with extended de-icing boots in accordance with Avions de Transport Regional Service Bulletin ATR42-30-0063, Revision 2, dated October 1, 1999 (for Model ATR42 series airplanes), or ATR72-30-1032, Revision 2, dated October 1, 1999 (for Model ATR72 series airplanes); as applicable.
(b) Within 30 months after the effective date of this AD, install de-icing boots on the metallic wing leading edge in accordance with Avions de Transport Regional Service Bulletin ATR42-30-0064, Revision 2, dated October 1, 1999 (for Model ATR42 series airplanes), or ATR72-30-1033, Revision 2, dated October 1, 1999 (for Model ATR72 series airplanes); as applicable.
(c) Within 30 months after the effective date of this AD, modify the ICING light flashing logic of the Anti-icing Advisory System (AAS), in accordance with Avions de Transport Regional Service Bulletin ATR42-30-0065, Revision 2, dated October 25, 1999 (for Model ATR42 series airplanes), or Avions de Transport Regional Service Bulletin ATR72-30-1034, Revision 2, dated October 19, 1999 (for Model ATR72 series airplanes); as applicable.
Note 2: Accomplishment of the boot replacement, boot installation, and modification is also considered acceptable for compliance with the applicable requirements of paragraphs (a), (b), and (c) of this AD, if accomplished in accordance with Revision 1 of the following Avions de Transport Regional service bulletins: (For Model ATR42 Series Airplanes) ATR42-30-0063, May 7, 1999, ATR42-30-0064, May 7, 1999, ATR42-30-0065, May 17, 1999 (For Model ATR72 Series Airplanes) ATR72-30-1032, May 7, 1999, ATR72-30-1033, May 7, 1999, ATR72-30-1034, May 17, 1999.
