Airworthiness Directive · Amendment 39-11859 · Schweizer Aircraft Corporation Model 269A, 269A-1, 269B, 269C, 269C-1, 269D, and TH-55A Helicopters
Schweizer Aircraft Corporation Model 269A, 269A-1, 269B, 269C, 269C-1, 269D, and TH-55A Helicopters
Model 269A, 269A-1, 269B, 269C, 269C-1, 269D and TH-55A helicopters, with a tail rotor swashplate shaft (shaft), part number (P/N) 269A6049-3, or a tail rotor pitch control assembly (pitch control), P/N 269A6050-5, with a serial number (S/N) with an “S” prefix and number 1047 through 1061, 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 (c) 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 supersedes an existing airworthiness directive (AD) that applies to Schweizer Aircraft Corporation (Schweizer) Model 269A, 269A-1, 269B, 269C, 269C-1, 269D helicopters. That AD requires inspecting the tail rotor swashplate shaft (shaft) nut for looseness and, if loose, inspecting the shaft for proper size; subsequently inspecting the shafts not previously inspected; and replacing any undersized shaft prior to further flight. This amendment reduces the applicability by specifying certain serial number tail rotor pitch control (pitch control) assemblies and shipping dates but adds the Schweizer Model TH-55A helicopter to the applicability. This amendment is prompted by the discovery of an undersized replacement shaft during routine maintenance. The actions specified by this AD are intended to prevent failure of the shaft, loss of the tail rotor, and subsequent loss of control of the helicopter.
To prevent failure of the shaft, loss of the tail rotor, and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 10 hours time-in-service (TIS);
(1) Determine whether the factory-installed shaft, part number (P/N) 269A6049-3, has been replaced with a shaft shipped from the factory between September 1 and December 1, 1998, inclusive, or if a pitch control, P/N 269A6050-5, with a S/N with an “S” prefix and numbers 1047 through 1061 is installed.
(2) If the factory ship date for a replacement shaft cannot be positively determined, if the shipping date was between September 1 and December 1, 1998, inclusive, or if the pitch control S/N has an “S” prefix and number 1047 through 1061,
(i) Before further flight and thereafter at intervals not to exceed 10 hours TIS, accomplish “Procedure, Part I,” of Schweizer Service Bulletins B-271.1 for Models 269A, 269A-1, 269B, 269C and TH-55A helicopters; C1B-009.1 for the Model 269C-1, or DB-007.1 for the Model 269D, all dated October 14, 1999 (SB), as applicable.
(ii) At the next scheduled 100-hour or annual inspection, whichever occurs first, accomplish Part II, paragraphs a. through d., of the applicable SB. Shafts not meeting the requirements of paragraph d. of the applicable SB must be replaced with an airworthy shaft prior to further flight.
(b) Before installing a replacement shaft, determine the date the shaft was shipped from the factory. If the date was between September 1 and December 1, 1998, inclusive, or cannot be determined, accomplish the inspections required by Part II, paragraph d., of the applicable SB prior to installation. Replace any unairworthy shaft with an airworthy shaft.
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.
