# AD 66-14-01: Wing Main Spar - Type: Airworthiness directive - Status: Current - Products: Thrush 600-S-2C, S-2B, S-2C and S2A - Effective: July 5, 1966 - Published: June 3, 1966 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-246 - Registered aircraft: 18 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/80930D35BCC450C186256A34004841B7.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/66-14-01 ## The airworthiness directive 66-14-01 AERO COMMANDER (SNOW): Amdt. 39-246 Part 39 Federal Register June 3, 1966. Applies to Models S-2A, S-2B, S-2C, and 600 S-2C Airplanes. Compliance required as indicated, unless already accomplished. To prevent fatigue cracks in the lower spar cap of the wing main spar, accomplish the following: (a) For Model S-2A airplanes with 1,400 or more hours' time in service on the effective date of this AD - (1) Comply with (k) within the next 100 hours' time in service and comply with (l) within the next 1,500 hours' time in service after complying with (k); or (2) Comply with (l) within the next 100 hours' time in service. (b) For Model S-2A airplanes with less than 1,400 hours' time in service on the effective date of this AD - (1) Comply with (k) before the accumulation of 1,500 hours' time in service and comply with (l) within the next 1,500 hours' time in service after complying with (k); or (2) Comply with (l) before the accumulation of 1,500 hours' time in service. (c) For Models S-2B and S-2C airplanes, Serial Number 1189 and below, powered by 450 hp. engines, with 900 or more hours' time in service on the effective date of this AD - (1) Comply with (k) within the next 100 hours' time in service and comply with (l) within the next 1,000 hours' time in service after complying with (k); or (2) Comply with (l) within the next 100 hours' time in service. (d) For Models S-2B and S-2C airplanes, Serial Number 1189 and below, powered by 450 hp. engines, with less than 900 hours' time in service on the effective date of this AD - (1) Comply with (k) before the accumulation of 1,000 hours' time in service and comply with (l) within the next 1,000 hours' time in service after complying with (k); or (2) Comply with (l) before the accumulation of 1,000 hours' time in service. (e) For Model S-2C airplanes, Serial Numbers 1190 through 1231, powered by 450 hp. engines, with 900 or more hours' time in service on the effective date of this AD, comply with (l) within the next 100 hours' time in service. (f) For Model S-2C airplanes, Serial Numbers 1190 through 1231, powered by 450 hp. engines, with less than 900 hours' time in service on the effective date of this AD, comply with (l) before the accumulation of 1,000 hours' time in service. (g) For Models S-2C and 600 S-2C airplanes, Serial Number 1189 and below, powered by 600 hp. engines, with 600 or more hours' time in service on the effective date of this AD - (1) Comply with (k) within the next 100 hours' time in service and comply with (l) within the next 700 hours' time in service after complying with (k); or (2) Comply with (l) within the next 100 hours' time in service. (h) For Models S-2C and 600 S-2C airplanes, Serial Number 1189 and below, powered by 600 hp. engines, with less than 600 hours' time in service on the effective date of this AD - (1) Comply with (k) before the accumulation of 700 hours' time in service and comply with (l) within the next 700 hours' time in service after complying with (k); or (2) Comply with (l) before the accumulation of 700 hours' time in service. (i) For Models S-2C and 600 S-2C airplanes, Serial Numbers 1190 through 1231, powered by 600 hp. engines, with 600 or more hours' time in service on the effective date of this AD, comply with (l) within the next 100 hours' time in service. (j) For Models S-2C and 600 S-2C airplanes, Serial Numbers 1190 through 1231, powered by 600 hp. engines, with less than 600 hours' time in service on the effective date of this AD, comply with (l) before the accumulation of 700 hours' time in service. (k) Install modified wing center splice in accordance with Snow Service Letter No. 29 or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Southwest Region. (l) Install wing lower steel spar caps in accordance with Snow Drawing No. 5-1089, Revision D, or an equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Southwest Region. (Snow Service Letter No. 36 pertains to this subject.) This directive effective July 5, 1966. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 2A7](https://openairdocs.org/tcds/2A7): Thrush Aircraft LLC; names 3 of 3 models: S-2C, 600 S-2C, S-2B - [TCDS 2A9](https://openairdocs.org/tcds/2A9): Thrush Aircraft LLC; names 1 of 1 models: S2A ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 18 (18 by airframe model, 0 by engine model) - Makers: Snow 18 Models with the most aircraft: - [Snow S2A](https://openairdocs.org/model/snow-s2a): 6 aircraft (airframe model) - [Snow S2C](https://openairdocs.org/model/snow-s2c): 6 aircraft (airframe model) - [Snow 600-S2C](https://openairdocs.org/model/snow-600-s2c): 6 aircraft (airframe model) All 3 models: https://openairdocs.org/ad/66-14-01/models.md Every aircraft: https://openairdocs.org/ad/66-14-01/aircraft.md Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB CHI78FEP45](https://openairdocs.org/ntsb/CHI78FEP45), Jul 11, 1978: Snow S2C (N1638S), Bancroft, WI, destroyed --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.