AD 75-13-06

75-13-06 BRITISH AIRCRAFT CORPORATION: Amendment 39-2236. Applies to Viscount Model 700 Series airplanes certificated in all categories.

Compliance required as indicated.

To prevent the possible in-flight fatigue failure of the horizontal stabilizer, accomplish the following:

(a) For horizontal stabilizer rear spars with more than 25,000 landings on the effective date of this AD, comply with paragraphs (c) and (d) of this AD within the next 10 landings or 50 hours time in service, whichever occurs first, unless already accomplished.

(b) For all horizontal stabilizer rear spars not covered in paragraph (a) of this AD, comply with paragraphs (c) and (d) of this AD before the accumulation of 20,000 total landings or the lesser of 100 landings or 300 hours time in service after the effective date of this AD, whichever occurs later, unless already accomplished.

(c) Inspect the rear spar of the left and right horizontal stabilizer for cracks and corrosion, and repairor replace as necessary, in accordance with CAA-approved British Aircraft Corporation (BAC) Alert Preliminary Technical Leaflet (PTL) No. 298, Issue 1, dated August 16, 1974, or an FAA-approved equivalent.

(d) Accomplish BAC Modification Leaflet D.3268 or D.3269, or an FAA-approved equivalent of either, as provided in BAC PTL NO. 298, Issue 1.

(e) Spar booms on which the corrosion damage exceeds the limits set forth in BAC PTL No. 298, Issue 1, may not be returned to service unless the repair of such damage is approved by the Chief, Aircraft Certification Staff, Europe, Africa, and Middle East Region of the FAA.

(f) The service life limitation of the rear spar assembly of a spar boom modified in accordance with BAC Modification Leaflet D.3268, or an FAA-approved equivalent, is 2000 landings after modification or 30,000 total pre-modification and post-modification landings, whichever occurs first.

(g) The service life limitation of the rear spar assembly of a spar boom modified in accordance with BAC Modification Leaflet D.3269, or an FAA-approved equivalent, is 30,000 total pre-modification and post- modification landings.

(h) For the purpose of this AD, the number of landings may be determined by actual count, or, subject to the acceptance of the assigned FAA maintenance inspector, by dividing the horizontal stabilizer spar total time in service by an average flight time determined from the airplane log book to be representative for that airplane. Operators who have not kept records of landings or time in service for individual horizontal stabilizers must substitute total number of airplane landings or time in service in place thereof.

This amendment becomes effective June 6, 1975.