Airworthiness Directive · Amendment 39-17276 · Flight controls
Saab AB, Saab Aerosystems Airplanes
Superseded. A later AD replaced this one: AD 2016-22-15. Comply with the one in force.
This AD applies to Saab AB, Saab Aerosystems Model 340A (SAAB/SF340A) and SAAB 340B airplanes, certificated in any category, as identified in paragraphs (c)(1) and (c)(2) of this AD, except airplanes that have SAAB Modification 2650 and/or 2859 installed. This AD does not apply to airplanes with serial numbers 170, 342, 362, 363, 367, 372, 379, 385, 395, 405, 409, 431, and 455.
(1) Model 340A (SAAB/SF340A) airplanes, serial numbers 004 through 159 inclusive.
(2) Model SAAB 340B airplanes, serial numbers 160 through 459 inclusive.
We are adopting a new airworthiness directive (AD) for certain Saab AB, Saab Aerosystems Model 340A (SAAB/SF340A) and SAAB 340B airplanes. This AD was prompted by reports of stall events during icing conditions where the natural stall warning (buffet) was not identified. This AD requires replacing the stall warning computer (SWC) with a new SWC, which provides an artificial stall warning in icing conditions, and modifying the airplane for the replacement of the SWC. We are issuing this AD to prevent natural stall events when operating in icing conditions, which, if not corrected, could result in loss of control of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
(1) For airplanes with basic wing tips: Within 24 months after the effective date of this AD, replace all stall warning computers (SWCs) having part number (P/N) 0020AK, 0020AK1, 0020AK2, or 0020AK4, with a new SWC P/N 0020AK6, in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-27-098, Revision 01, dated April 13, 2012.
(2) For airplanes with extended wing tips: Within 24 months after the effective date of this AD, replace the SWC P/N 0020AK3 MOD 1 with a new SWC P/N 0020AK7, in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-27-099, Revision 01, dated April 13, 2012.
Before or concurrently with the accomplishment of the requirements of paragraph (g) of this AD: Modify the airplane in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-27-097, Revision 03, dated April 19, 2012.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
