ASB 412-11-148 Rev A Page 1 of 4

ECCN EAR99 ALERT SERVICE BULLETIN 412-11-148 15 September 2011
Revision A, 12 December 2011

MODEL AFFECTED: 412/412EP

SUBJECT: COLLECTIVE LEVER 412-010-408-101, 100 HOUR

SPECIAL INSPECTION INTRODUCTION OF

HELICOPTERS AFFECTED: Serial num ber 33001 through 33213, S/N 34001 through 34036 and 36001 through subsequent.

[Serial numbers 36571 and subsequent will have the intent of this bulletin accomplished prior to delivery. Recurring inspection will be required as indicated in the COMPLIANCE section]

COMPLIANCE: Within the next 100 hours accumulated on the collective lever or 90 days after release of this bulletin whichever comes first and every 100 hours

accumulated on the collect ive lever thereafter.

DESCRIPTION:

Revision A allows the lower side of the colle ctive lever to be visually inspected with a mirror (no magnifying glass) due to diffi cult access. Other changes are also incorporated for clarity.

Bell Helicopter has received a report of a fractured colle ctive lever 412-010-408-101. The investigation has revealed that resi dual stresses induced duri ng manufacturing may have contributed to the fatigue fracture. This anomaly in the forging that could lead to cracking cannot be detected using existing Non Destructive Inspection methods. This Alert Service Bulletin introduces a recurring 100 hrs 10 X magnifying glass inspection of

the collective lever. The Maintenance Manual wi ll be revised to include the intent of this

Alert Service Bulletin as a 100 hour Special Inspection (Mandatory Structural Inspection). Applicability of this bulletin to any spare part shall be determined prior to its installation on an affected helicopter.

APPROVAL:

The engineering design aspects of th is bulletin are FAA/ODA approved.ASB 412-11-148 Rev A Page 2 of 4

ECCN EAR99 CONTACT INFO:

For any questions regarding this bulletin, please contact:

Bell Helicopter Product Support E ngineering - Medium Helicopters Tel: 450-437-6201 / 1-800-363-8028 / psem edium@bellhelicopter.textron.com

MANPOWER:

The man-hours required to comple te this bulletin are negligib le. This estimate is based on hands-on time, and may vary with per sonnel and facilities available.

WARRANTY:

There is no warranty credit applicable for parts or labor associated with this bulletin.

MATERIAL:

Required Material: The following material may be required for t he accomplishment of this bulletin and may be obtained through your Bell Helic opter Textron S upply Center.

Part Number Nomenclature Qty

412-010-408-101 Collective lever assembly (Note)

Note: Ordering will be required only if a crack is found.

Consumable Material: The following material is required to acco mplish this bulletin, but may not require ordering, depending on t he operator’s consumable material stock levels. This material may be obtained through your Bell He licopter Textron Supply Center.

Part Number Nomenclature Qty Reference *

MILC87936TYI Cleaning Compound A/R C-318

* C-XXX numbers refer to the co nsumables list in BHT-ALL-SPM Standard Practices Manual

SPECIAL TOOLS:

None required.ASB 412-11-148 Rev A Page 3 of 4

ECCN EAR99 WEIGHT AND BALANCE:

Not affected.

ELECTRICAL LOAD DATA:

Not affected.

REFERENCES:

BHT-412-MM, Maintenance Manual

BHT-ALL-SPM

PUBLICATIONS AFFECTED:

BHT-412-MM, Maintenance Manual

ACCOMPLISHMENT INSTRUCTIONS:

Collective lever inspection.

1. Prepare helicopter for maintenance.

a. Gain access to the collective lever.

2. Using cleaning compound (C-318) or equ ivalent, thoroughly clean the collective lever in preparation for inspection.

3. Using a strong light source and a 10X magn ifying glass, inspect the collective lever in the area shown on Figure 1. Due to difficu lt access, it is acceptable to inspect the

lower side of the affected area with a st rong light source and a mirror only.

4. Look for evidence of crack in the paint.

5. If a crack is suspected, remove the colle ctive lever from the swashplate assembly. (BHT-412-MM)

a. Perform a Fluorescent Penetrant Inspec tion with local paint and primer removed in the suspected area. (BHT-ALL-SPM.

6. If a crack is found, replace the collect ive lever with a serviceable part and contact Product Support Engineering to report the defect.

7. If no crack is found, refini sh as required per BHT-412-CR&O and make an entry in the helicopter records to indicate findi ngs and compliance with this Alert Service

Bulletin.ASB 412-11-148 Rev A Page 4 of 4

ECCN EAR99 Figure 1. Collective lever inspection.