SAIB CE-04-33 —

1 SPECIAL AIRWORTHINESS INFORMATION BULLETIN

Aircraft Certification Service Washington, DC

U.S. Department of Transportation Federal Aviation Administration

No. CE-04-33 December 11, 2003 www.faa.gov - Search "SAIBs" This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin informs you, owners and operators of the Commander Aircraft Company (Rockwell International) Model 112 and 114 aircraft listed below, of the potential for cracking in the flange radius of the Wing Station (WS) 66.00 Leading Edge Rib aft attach angle.

Model Serial Numbers 112 471 through 499 112B 500 through 544 112TC 13000 through 13149 112TCA 13150 through 13286 114 14000 through 14454

Background

We received a report of cracks in the left and right WS 66.00 Leading Edge Rib aft attach angles on a Model 114 airplane. On the above listed Commander Model 112 and 114 airplanes, the aft end of the WS 66.00 Leading Edge Rib attaches to the auxiliary front spar by a “zee” angle. The reported cracks travel up the zee bend radius between the 2 legs where the angle attaches to the rib and auxiliary spar. A doubler plate with captive nuts covers the lower half of the forward face of the aft flange, masking the crack until it grows above the end of the doubler (see attached figures).

Recommendation

We strongly recommend that, starting at the next maintenance interval, and at each annual inspection thereafter, you visually inspect the WS 66.00 Leading Edge Rib aft attach angle and surrounding area for cracks. These actions will help insure the continued airworthiness of your airplane.

Using a flashlight and extension mirror, inspect for evidence of cracking, paying particular attention to the aft flange radius. Gain access through the wheel well and insert the inspection mirror through lightening holes in the auxiliary spar web and WS 66 rib. You can gain alternate access through the lower wing access panel, centered at WS 78.3 between the WS 66.00 and WS 82.5 ribs forward of the auxiliary spar.

Replace any part found cracked before continued flight. Report any cracks found, including crack location and size, to the FAA point of contact listed below.

2 For Further Information Contact

Andrew McAnaul, Aerospace Engineer, DOT/FAA, SAT SW-MIDO-43, 10100 Reunion Place, Suite 650, San Antonio, TX 78216; phone: (210) 308-3365; fax: (210) 308-3370; e-mail: [email protected]

Figure 1. Front View Showing Crack Extending Above The Aft Flange Doubler

Crack Doubler Lower Rib Surface

3

Figure 2. Aft View of Crack Extending Up Aft Flange Radius

Figure 3. WS 66.00 Rib Crack Area Zee Angle Aft Flange Crack Auxiliary Spar