Adds Models To AD Covering Exhaust Systems On The Aircraft

The FAA has posted a proposed revision to an NPRM for an AD that originally applied to Models A36TC and B36TC airplanes. The revision adds all Textron Aviation Inc. Models S35, V35, V35A, and V35B airplanes that have the optional turbocharger engine installed to the applicability and adding an annual visual inspection of the exhaust tailpipe v-band coupling (clamp).

The original NPRM, published in the Federal Register on April 12, 2017 (82 FR 17594), was prompted by a fatal accident where the exhaust tailpipe fell off during takeoff. The NPRM proposed to add a life limit to the exhaust tailpipe v-band coupling (clamp) and, if the coupling is removed for any reason before the life limit is reached, require an inspection of the vband coupling before reinstalling.

Since that NPRM was issued, the FAA received information that Textron Models S35, V35, V35A, and V35B airplanes could have a turbocharged reciprocating engine installed, either at manufacture as an optional installation or post-manufacture as a supplemental type certificate (STC) installation. Either engine installation would include installation of an affected v-band coupling. The agency also received comments to the NPRM requesting an annual visual inspection of the v-band couplings and requesting language changes to address the replacement of the engine with a non-turbocharged engine.

The NTSB requested that the FAA add repetitive visual inspections of the vband coupling. The NTSB noted that the FAA included repetitive visual inspections of the v-band coupling in a previous AD affecting Piper Aircraft Inc. airplanes. They believe a similar repetitive visual inspection of the vband coupling for the airplanes affected by this proposed AD, in addition to the proposed life limit, would help identify the cracks before failure. The FAA agreed with the comment, and has added a repetitive visual inspection of the v-band coupling to this SNPRM.

The FAA estimates that this proposed AD affects 731 airplanes of U.S. registry. The estimates costs to comply with this proposed AD include:

• Visual inspection of the exhaust tailpipe v-band coupling (Installed); $42.50
• Replacement of the exhaust tailpipe vband coupling; $470 per aircraft for parts and labor
• Inspection of the exhaust tailpipe v-band coupling (Not installed, includes removal and reinstallation); $127.50
• Installation of part number N1000897–40 exhaust tailpipe v-band coupling;  $632 per aircraft for parts and labor.

Comments must be received on this SNPRM by December 26, 2017.  

(Image from file)

FMI: www.gpo.gov/fdsys/pkg/FR-2017-11-08/pdf/2017-24065.pdf