Airworthiness Directive · Amendment 39-17770 · Tail rotor blades
Airbus Helicopters (Type Certificate Previously Held by Eurocopter France) (Airbus Helicopters)
This AD applies to Model AS350B, BA, B1, B2, B3, D; and AS355E, F, F1, F2, and N helicopters with a tail rotor (T/R) blade, part number (P/N) 355A12-0040-00, 355A-12-0040-01, 355A12-0040-02, 355A12-0040-03, 355A-12-0040-04, 355A12-0040-05, 355A-12-0040-07, 355A-12-0040-08, all serial numbers (S/N); or P/N 355A12-0050-04, with a S/N 8400 through 9224, certificated in any category.
We are adopting a new airworthiness directive (AD) for Airbus Helicopters Model AS350B, BA, B1, B2, B3, and D, and Model AS355E, F, F1, F2, and N helicopters with certain tail rotor (T/R) blades. This AD requires installing additional rivets to secure each T/R blade trailing edge tab (tab), and inspecting for evidence of debonding of the tab after the rivets are installed. This AD was prompted by reports of T/R blade tab debonding. The actions of this AD are intended to prevent loss of a T/R blade tab, which could result in excessive vibration and loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 100 hours time-in-service, install additional rivets on the trailing edge tab of each T/R blade, according to the following procedures, referencing Figure 1 of Eurocopter Alert Service Bulletin (ASB) No. 64.00.05, Revision 2, dated February 15, 2007, or ASB No. 64.00.04, Revision 2, dated February 15, 2007, whichever is applicable to your model helicopter:
(1) Lightly sand the area to be drilled, using No. 80 then No. 220 sandpaper.
(2) Locate and drill eight 2.5 mm-diameter holes (T): 4 holes (T) 12 mm from the existing rivets (E) and on the centerline of the existing rivets (E), then 4 holes (T) 24 mm from the existing rivets (E) and on the centerline of the existing rivets (E).
(3) Deburr and clean the area around the drilled holes.
(4) Install 8 rivets (1) on tab (L). Any installation direction of the rivets is permissible (pressure face or suction face of the T/R blade).
(5) Inspect the tab for debonding.
(i) If there is no debonding, paint the area.
(ii) If there is debonding, replace the tab.
