Potential For Corrosion In Empennage Structure Found On Some Airplanes

The FAA's Wichita Aircraft Certification Office (ACO), has received reports from the Beechcraft Repair Design Office (RDO) of approximately 100 repairs in the past decade to address structural corrosion of the empennage.

Typically, the RDO is consulted when corrosion levels exceed repair limits governed by the standard repair manual (SRM). In the reported cases, Beechcraft cited that the most extreme corrosion was experienced on the rear spar cap (or chord) of both the horizontal and vertical stabilizers. However, corrosion damage was not limited to those areas and was also discovered inside the horizontal and vertical stabilizers.

In response to the reports, the FAA has issued a Special Airworthiness Information Bulletin (SAIB) intended to inform owners, operators, and maintenance personnel of Beechcraft Corporation (Beechcraft) (formerly Hawker Beechcraft, Raytheon Aircraft, and Beech Aircraft Corporation) King Air Model F90 airplanes and King Air Series 200, B200, 300, B300, and Commuter 1900 Series airplanes (specific models on type certificate data sheet A24CE) of the issue.

Although the horizontal and vertical stabilizers were originally designed with access panels, Beechcraft has designed kits for the installation of additional access panels in order to facilitate more thorough inspections of these areas.

Beechcraft has also revised the Airworthiness Limitations Manual (ALM) of the Instructions for Continuing Airworthiness (ICA) for the affected models. The respective ALM’s refer to inspections defined in the SRM for each model.

The FAA recommends that the latest revision of the airworthiness limitations be incorporated for the affected airplanes. Doing so will ensure corrosion inspections for both the horizontal and vertical stabilizers are included in the maintenance program. The respective Airworthiness Limitations are included in the following documents:

• Airworthiness Limitations Section of King Air F90 Series Maintenance Manual Part No. 109-590010-19 Revision B7, May 2014;
• Airworthiness Limitations Manual King Air 200 Series
• Part No. 101-590010-453 Revision E, February 2015;
• Airworthiness Limitations Manual King Air 300/300LW
• Part No. 101-590097-161 Initial Revision, May 2011;
• Airworthiness Limitations Manual King Air B300/B300C
• Part No. 130-590031-211 Revision D, February 2015;
• Airworthiness Limitations Manual Model 1900 Airliner Series Part No. 129-590000-133 Revision C, August 2014

All of the Airworthiness Limitations utilize similar instructions to inspect the horizontal and vertical stabilizers for corrosion. The model specific Structural Inspection and Repair Manuals are as follows:

• For the horizontal stabilizer on F90, 200 Series, 300 and B300 Series airplanes, utilize Chapter 55-00-11 of the Structural Inspection and Repair Manual 98-39006 Revision C10, Nov 2013.
• For the vertical stabilizer on F90, 200 Series, 300 and B300 Series airplanes, utilize Chapter 55-00-12 of the Structural Inspection and Repair Manual 98-39006 Revision C10, Nov 2013.
• For the horizontal and vertical stabilizers on Model 1900/1900C airplanes, utilize Structural Inspection Manual 98-30937 Revision G3, August 1, 2014 “I” Check Procedures.
• For the horizontal and vertical stabilizers on Model 1900D airplanes, utilize Structural Inspection Manual 129-590000-65 Revision E6, August 1, 2014 “I” Check Procedures.

In order to accomplish the recommended inspections internal to the horizontal and vertical stabilizers, Beechcraft has designed additional inspection access kits. The kits are referenced in the ALM. We recommend that these access kits be incorporated.

FMI: SAIB