Airworthiness Directive · Amendment 39-11626 · Sikorsky Model S-61 Helicopters
Sikorsky Model S-61 Helicopters
Superseded. A later AD replaced this one: AD 2000-13-06. Comply with the one in force.
Model S-61 helicopters with pylon, part number (P/N) S6120-76265-001 or S6120-76266-507, installed, certificated in any category.
Note 1: This AD applies to each helicopter 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 helicopters 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 (b) 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 Sikorsky Model S-61 helicopters. This action requires inspecting certain pylon upper and lower hinge web fittings (web fittings) for corrosion or a crack and either repairing certain web fittings or replacing any unairworthy web fittings with airworthy web fittings. The AD also requires creating a log card or equivalent record and implementing a recurring inspection of the web fittings. This amendment is prompted by the discovery of extensive cracking in the area of the web fittings. The actions specified in this AD are intended to prevent structural failure of the tail boom due to a crack or corrosion of certain web fittings and subsequent loss of control of the helicopter.
To prevent structural failure due to a crack or corrosion of pylon upper and lower hinge web fittings (web fittings), P/N S6120-76261-012, -013 (upper) or S6120-76262-012, -013 (lower), and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 25 hours time-in-service (TIS),
(1) Determine the alloy-temper of the web fittings in accordance with Sikorsky Aircraft Corporation Alert Service Bulletin No. 61B20-33, dated September 3, 1999 (ASB), Accomplishment Instructions, paragraph 3.A.
(2) Prepare the web fittings for inspection in accordance with the ASB Accomplishment Instructions, paragraph 3.B.
(3) Inspect the web fitting in accordance with the ASB Inspection Plan, Chart A, and the Accomplishment Instructions, paragraphs 3.C., 3.D, and 3.E. Nicks, scratches, corrosion pitting or prior rework beyond the limits specified in paragraph 3.C.(5) require approval by the FAA.
(4) Repair or replace web fittings, as necessary, in accordance with the ASB Accomplishment Instructions, paragraph 3.C.(3) through (6). Nicks, scratches, corrosion pitting, or prior rework beyond the limits specified in paragraph 3.C.(5) require approval by the FAA.
(5) If replacing an unairworthy web fitting with an airworthy web fitting, replace it in accordance with the ASB Accomplishment Instructions, paragraph 3.F., prior to further flight.
(6) Create a log card for the pylon, if none exists. Make an entry on the log card or equivalent record implementing recurring inspection intervals in accordance with Chart A of the ASB.
