HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp 1. Planning Information A. Effectivity Hartzell propeller models ( )HC-( )( )MV( )-( )( ) that have D-6831-( ) single shoulder blade clamps installed are affected by this Service Bulletin. B. Concurrent Requirements None C. Reason (1)

There have been two aircraft with a total of five cracked D-6831-5A clamps discovered. In both instances the cracks appear to have initiated due to an unusual and aggressive form of corrosion. The cracks initiated on the interior surface of the clamp at the inboard bearing retention radius near the clamp parting line. There were no signs of unusual vibration in either case.

(2)

An unusual form of corrosion, possibly caused by bacteria, has been observed. If left undetected, this corrosion may lead to a crack that could result in clamp failure. Clamp failure can result in the loss of the propeller blade and aircraft. Inspection of the affected clamps in accordance with this Bulletin will detect a crack before it has an opportunity to fully develop.

(3)

A special cleaning procedure, specified in the Accomplishment Instruction section of this Bulletin, has been implemented to eliminate suspect bacteria.

D. Description (1)

This Bulletin provides instructions for visual inspection of the affected clamps to detect cracks.

(2)

This Bulletin provides instructions for overhaul of the propeller, to be performed if a crack is discovered during the visual inspection of the clamp.

(3)

This Bulletin requires a repetitive 100 hour inspection of the affected blade clamps. A terminating action for this Bulletin is currently being studied, but will require further research and results from this Bulletin.

Dec 20/01

HC-ASB-61-255 Page 1 of 7

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp E. Compliance (1)

If new blade clamps were installed as part of an upgrade from V to MV blade clamps: If time since new (TSN) of the blade clamp is greater than or equal to 1,000 hours, a visual inspection of the outer surface of the blade clamp must be accomplished within 10 flight hours, with subsequent visual clamp inspection at every 100 hours.

(2)

If a new MV propeller was purchased: If time since new (TSN) of the propeller is greater than or equal to 1,000 hours, a visual inspection of the outer surface of the blade clamp must be accomplished within 10 flight hours, with subsequent visual clamp inspection at every 100 hours.

NOTE:

Removal of the spinner is necessary, but disassembly of the clamp is not required for compliance with this Bulletin.

F. Approval FAA approval has been obtained on technical data in this publication that affects type design. G. Manpower Approximately 1.0 man-hour per propeller assembly is required to remove the spinner and perform a visual inspection of the blade clamps for compliance with this Service Bulletin. H. Weight and Balance Not changed I.

Electrical Load Data Not changed

J. References Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00) Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14) Hartzell Aluminum Blade Overhaul Manual 133C (61-13-33) Hartzell Propeller Owner's Manual 168 (61-00-68) Hartzell Standard Practices Manual 202A (61-01-02) K. Other Publications Affected None

Dec 20/01

HC-ASB-61-255 Page 2 of 7

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp 2. Material Information The following material is necessary for clamp replacement (if a crack is discovered in a clamp during visual inspection in accordance with this bulletin). Standard replacement parts are also required for propeller overhaul. Part Number

Key Word

Qty.

838-( )

Clamp Assembly

AR

3. Accomplishment Instructions A. Visual Clamp Inspection (1)

Remove the spinner dome in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14) or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable.

A-321 Screw

Using 10 x magnification, visually inspect the external surfaces around the circumference of the clamp, focusing in this area.

Blade Clamp Inspection Figure 1

Dec 20/01

HC-ASB-61-255 Page 3 of 7

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp WARNING:

SERIOUS PROPELLER DEFECTS MAY GIVE INDICATIONS BEFORE FAILURE, SUCH AS SUDDEN OR ABNORMAL GREASE LEAKAGE OR VIBRATION DURING OPERATION. AN IN-FLIGHT BLADE SEPARATION CAN RESULT IN A CATASTROPHIC AIRCRAFT ACCIDENT. IF ABNORMAL GREASE LEAKAGE OR VIBRATION ARE PRESENT, PROPELLER INSPECTION MUST BE PERFORMED BEFORE FURTHER FLIGHT. ADDITIONALLY, REFER TO HARTZELL SERVICE LETTER HC-SL-61-165, WHICH ADDRESSES ABNORMAL VIBRATION OR GREASE LEAKAGE.

(2)

Prior to any cleaning, visually inspect the blade clamp for traces of grease. A blade clamp can have traces of grease coming from a crack that would make the crack more readily visible.

(3)

Carefully remove any grease or other matter from the surface that may hinder visual examination of the blade clamps.

(4)

Using 10 x magnification, visually inspect the outer surfaces of each blade clamp for cracks. Refer to Figure 1 for a description of the areas on which to focus the inspection.

(5)

If no cracks are discovered during visual inspection of the blade clamp (a)

Reinstall the spinner in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14) or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable.

(b)

Indicate compliance with this Service Bulletin in the propeller logbook and note when the next clamp inspection is due.

CAUTION: (6)

Dec 20/01

DO NOT FURTHER CLEAN THE CLAMP IF A CRACK IS DISCOVERED.

If a crack is discovered during visual inspection of the blade clamp, remove the propeller from the aircraft in accordance with Hartzell Propeller Owner's Manual 168 (61-00-68) and return it to an authorized propeller repair facility for propeller overhaul and optical comparator inspection of the blade shanks in accordance with section 3.B of this Bulletin.

HC-ASB-61-255 Page 4 of 7

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp B. Propeller Overhaul and Optical Comparator Inspection of Blade Shank NOTE:

The following procedures must be performed if a crack is discovered during the visual inspection of the blade clamps. Refer to 3.A. of this Bulletin.

(1)

Remove the propeller from the aircraft in accordance with Hartzell Propeller Owner's Manual 168 (61-00-68).

(2)

Perform propeller overhaul procedures in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14) or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable.

(3)

Disassemble each blade clamp. Refer to Disassembly in the Blade Clamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02).

(4)

Visually inspect the blade clamp for cracks.

CAUTION:

DO NOT CLEAN THE CLAMP IF A CRACK IS DISCOVERED.

(a)

If a crack is discovered in the clamp, do not clean the clamp. Put the clamp into a clean, sealed, plastic bag and return it to Hartzell Propeller for evaluation.

(b)

If no cracks are detected, proceed to step 3.B.5.

(5)

Strip the cadmium plating from each blade clamp. Refer to Cleaning in the Blade Clamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02).

(6)

Inspect each blade clamp in accordance with the Inspection section in the Blade Clamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02).

(7)

Magnetic particle inspect each blade clamp in accordance with the Magnetic Particle Inspection chapter of Hartzell Standard Practices Manual 202A (61-01-02), focusing on the interior surfaces at the inboard bearing retention radius of the clamp.

(8)

(a)

If a crack is discovered in the clamp, put the clamp in a clean, sealed, plastic bag and return it to Hartzell Propeller for evaluation.

(b)

If no cracks or other indications are detected, proceed to step 3.B.8.

Rework each blade clamp as necessary. Refer to the Repair section in the Blade Clamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02). (a)

Dec 20/01

If the blade clamp has been reworked to its maximum repair limit and still contains defects, return the clamp to Hartzell Propeller. Refer to the Inspection and Repair Criteria section in the Blade Clamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02). HC-ASB-61-255 Page 5 of 7

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp (9)

Thoroughly clean the clamp (a)

Using a clean paper towel soaked in a solution consisting of 70% by volume alcohol and 30% by volume distilled water, thoroughly wipe all surfaces of the clamp, using moderate pressure. The alcohol solution should consist of one of the following mixtures: 1

35% methanol (>99% pure ), 35% isopropyl alcohol (>99% pure) and 30% distilled water.

2

If 70% commercial grade isopropyl alcohol is used: 50% (70% isopropyl alcohol), 35% methanol (>99% pure ), and 15% distilled water.

3

If 91% commercial grade isopropyl alcohol is used: 40% (91% isopropyl alcohol), 35% methanol (>99% pure ), and 25% distilled water.

CAUTION 1:

TO MAINTAIN SOLUTION INTEGRITY, USE A FRESH BATCH OF ALCOHOL SOLUTION FOR EACH CLAMP. THE CONTAINER MUST BE CLEANED AFTER EACH USE .

CAUTION 2:

KEEP THE ALCOHOL SOLUTION COVERED AT ALL TIMES TO PREVENT EVAPORATION OF THE ALCOHOL.

(b)

Using the alcohol mixture as specified in 3.B.(9)(a), immediately immerse and soak each clamp in the solution for between five and ten minutes.

CAUTION:

(c)

Wipe the clamp thoroughly with a clean, dry paper towel.

WARNING:

(d)

THE CLAMP MUST BE THOROUGHLY WIPED FOLLOWING THE ALCOHOL SOLUTION SOAK TO REMOVE ANY TRACES OF FILM THAT ARE LEFT ON THE SURFACE OF THE CLAMP.

CLEANING AGENT METHYLETHYLKETONE (MEK) IS FLAMMABLE AND TOXIC TO THE SKIN, EYES AND RESPIRATORY TRACT. SKIN AND EYE PROTECTION ARE REQUIRED. AVOID PROLONGED CONTACT. USE IN A WELL VENTILATED AREA.

Rinse the clamp with acetone or MEK and allow it to dry.

(10) Apply an approved corrosion preventive compound to each clamp. (11) Cadmium plate each blade clamp in accordance with the Cadmium Replating chapter of Hartzell Standard Practices Manual 202A (61-01-02). (12) Repeat the cleaning procedure in 3.B.(9) for each clamp. (13) Paint the outside surface of each blade clamp. Refer to Painting in the Blade Clamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02). Dec 20/01

HC-ASB-61-255 Page 6 of 7

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETIN Propellers Propellers - Visual Inspection of Blade Clamp (14) Reassemble each blade clamp in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14), or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable. (15) Perform an optical comparator inspection of each blade shank in accordance with Appendix A - Optical Comparator chapter of Hartzell Aluminum Blade Overhaul Manual 133C (61-13-33). (a)

Blade shank retention areas that fall below the repair line on the comparator overlay are considered unairworthy and must be retired from service in accordance with the established procedure outlined in Hartzell Standard Practices Manual 202A (61-01-02).

(16) Reinstall each blade and blade clamp on the propeller assembly in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14), or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable. (17) Set blade angles and check blade track in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14), or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable. (18) Complete propeller assembly procedures in accordance with Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14) or Hartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), as applicable. (19) Indicate accomplishment of propeller overhaul in the propeller logbook. C. Appendix (1)

If a propeller overhaul for compliance with this Bulletin is necessary before the required overhaul time interval specified in Hartzell Service Letter HC-SL-61-61, contact Hartzell Propeller Product Support Department at (937) 778-4379 for warranty consideration and instructions.

(2)

Any findings discovered as a result of compliance with this Bulletin should be reported to Hartzell Propeller. Hartzell Propeller Inc. Product Support Department One Propeller Place Piqua, Ohio 45356 U.S.A.

Dec 20/01

Telephone: 937.778.4379 Fax: 937.778.4391 email: [email protected]

HC-ASB-61-255 Page 7 of 7