Rotor blade cracks

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FAA Aircraft Certification Service SPECIAL AIRWORTHINESS INFORMATION BULLETIN http://www.faa.gov/aircraft/safety/alerts/SAIB

SAIB: SW-07-28 Date: April 17, 2007 This is information only. Recommendations aren’t mandatory.

CORRECTED COPY – to add figure (page 2) inadvertently deleted from original

Introduction

This Special Airworthiness Information Bulletin (SAIB) alerts owners and operators of Brantly International, Inc., Model B-2B helicopters with main rotor blades, part number (P/N) 248-202 installed, that some of these rotor blades have developed cracks at the root area of the blade just aft of the main spar. In some cases, the rotor blade cracks have resulted in a section of the aft portion of the blade to separate from the aircraft resulting in large vibrations and emergency landings. Brantly has informed the FAA of these failures and is in the process of creating service information to address the rotor blade cracks. Background

Brantly International Inc., issued Service Letter No. 110, Revised October 31, 2005 to remind operators to perform the “Daily Inspections” described in the Maintenance Manual, Overhaul Instructions, And Parts Catalog, reissued May 15, 1981. The inspections are intended to be performed at least once daily before the start of the day’s flight activities. They also recommend that a visual check be incorporated into the pilot’s preflight inspection routine. They also state that you should inspect the upper and lower surface of the blade, paying close attention to the root of the main rotor outboard blades. Recommendations

As soon as possible, perform the inspections and pilot visual check specified in Service Letter No. 110 (attached).

In addition, we recommend that you remove the main rotor blade, P/N 248-202, from the helicopter and:

1) Inspect at the root near the fastener holes that attach the skins to the hinge block to 12 inches outboard of that area for cracks or stop drill holes (see figure below);

2) Eddy current or fluorescent penetrant inspect the same area as described in 1 above;

3) Replace any blade that reveals cracks or stop drilled holes with an airworthy component which also has these recommendations accomplished; and

4) Report any findings to the FAA contact person specified below.

For Further Information Contact

Marc Belhumeur, Aerospace Engineer, Rotorcraft Certification Office, ASW-170, 2601 Meacham Blvd., Fort Worth, Texas 76193; phone (817)222-5177; fax: (817) 222-5783, email: [email protected].

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Area for Inspection