Airworthiness Directive · Amendment 39-17446 · Fuselage
Twin Commander Aircraft LLC Airplanes
This AD applies to the following Twin Commander Aircraft LLC airplanes, certificated in any category:
(1) Model 690, all serial numbers except 11057;
(2) Model 690A, all serial numbers except 11104, 11106, 11129, 11134, 11146, 11159, 11173, 11192, 11220, 11237, 11252, 11263, 11280, 11287, 11298, 11303, 11317, 11339, and 11341; and
(3) Model 690B, all serial numbers except 11383, 11384, 11401, and 11436.
(4) Aircraft equipped with AVIADESIGN, Inc. STC No. SA5740NM (You may find information on STC No. SA5740NM at Internet: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/FEC5B7544E15F14C85256CC200122B19?OpenDocument&Highlight=sa5740nm) are not compatible with the modifications contained in Twin Commander Aircraft LLC Service Bulletin 241, dated September 26, 2012. When an airplane has been modified, altered, or repaired in the area addressed by the AD action, according to 14 CFR part 39.15, the AD action still applies to that airplane. Following 14 CFR 39.19, the owner/operator of that airplane must request approval from the FAA for an alternative method of compliance (AMOC) following the instructions in paragraph (j) of this AD.
We are adopting a new airworthiness directive (AD) for certain Twin Commander Aircraft LLC Models 690, 690A, and 690B airplanes. This AD requires inspection for cracking of the outer fuselage attachments, the lower wing main spar, the vertical channels, the upper picture window channels, aft cabin pressure web, external wing to fuselage fillets, and fasteners; repair or replacement of damaged parts as necessary; and modification of the structure with reinforced parts. This AD was prompted by cracks found in the upper picture window frame channels, left- and right-hand wing main spar frame support channels, and aft pressure bulkhead web. This condition, if not corrected, could result in structural failure of the airplane. We are issuing this AD to correct the unsafe condition on these products.
(1) Inspect the airplane structural components, at the compliance times specified in paragraphs (g)(1)(i) through (g)(1)(iv) of this AD following Part I of Twin Commander Aircraft LLC Service Bulletin 241, September 26, 2012:
(i) For airplanes with 10,000 or more hours time-in-service (TIS), inspect within the next 30 days after the effective date of this AD.
(ii) For airplanes with 7,500 through 9,999 hours TIS, inspect within the next 60 days after the effective date of this AD.
(iii) For airplanes with 5,000 through 7,499 hours TIS, inspect within the next 6 months after the effective date of this AD.
(iv) For airplanes with less than 5,000 hours TIS, inspect when the airplane accumulates a total of 5,000 hours TIS or within the next 12 months after the effective date of this AD, whichever occurs later.
If any damage, cracks, and/or cracks that exceed the allowable limits specified in the service bulletin are found during the inspection required in paragraph (g)(1) of this AD, before further flight, repair or replace parts as necessary following Twin Commander Aircraft LLC Service Bulletin 241, dated, September 26, 2012. If Twin Commander Aircraft LLC Service Bulletin 241, dated, September 26, 2012, does not give procedures for repair of the damaged area, before further flight, you must contact Twin Commander Aircraft LLC to obtain repair instructions approved by the Seattle Aircraft Certification Office (ACO) specifically for compliance with this AD and incorporate those instructions. You can find contact information for Twin Commander Aircraft LLC in paragraph (l)(2) of this AD.
(1) Before further flight after completing the actions in paragraphs (g) and (h) of this AD, modify and reassemble the airplane using the modification and reassembly procedures in Part II of Twin Commander Aircraft LLC Service Bulletin 241, dated, September 26, 2012.
(2) Although Twin Commander Aircraft LLC Service Bulletin 241, dated September 26, 2012, states that at least one person on the modification team must have completed the Twin Commander Aircraft LLC approved training, the FAA does not require that a mechanic complete this specialized training to do the modification work required in this AD. Regulations 14 CFR 65.81(a) and 14 CFR 65.81(b) provide criteria about qualifications of those performing maintenance; in this case, the requirements of this AD.
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.
