hartzell propeller inc. alert service bulletinmooney.free.fr/sauvegarde afs/hartzell/sb255.pdf ·...

HARTZELL PROPELLER INC.

ALERT SERVICE BULLETINPropellers

Propellers - Visual Inspection of Blade Clamp

HC-ASB-61-255 of 7

Dec 20/01

1. Planning Information

A. Effectivity

Hartzell propeller models ( )HC-( )( )MV( )-( )( ) that have D-6831-( ) single shoulderblade 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 clampsdiscovered. In both instances the cracks appear to have initiated due to anunusual and aggressive form of corrosion. The cracks initiated on the interiorsurface of the clamp at the inboard bearing retention radius near the clamp partingline. There were no signs of unusual vibration in either case.

(2) An unusual form of corrosion, possibly caused by bacteria, has been observed. Ifleft 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 ofthe affected clamps in accordance with this Bulletin will detect a crack before ithas an opportunity to fully develop.

(3) A special cleaning procedure, specified in the Accomplishment Instruction sectionof this Bulletin, has been implemented to eliminate suspect bacteria.

D. Description

(1) This Bulletin provides instructions for visual inspection of the affected clamps todetect cracks.

(2) This Bulletin provides instructions for overhaul of the propeller, to be performed if acrack is discovered during the visual inspection of the clamp.

(3) This Bulletin requires a repetitive 100 hour inspection of the affected bladeclamps. A terminating action for this Bulletin is currently being studied, but willrequire further research and results from this Bulletin.




Dec 20/01 HC-ASB-61-255 of 7

E. Compliance

(1) If new blade clamps were installed as part of an upgrade from V to MV bladeclamps: If time since new (TSN) of the blade clamp is greater than or equal to1,000 hours, a visual inspection of the outer surface of the blade clamp must beaccomplished within 10 flight hours, with subsequent visual clamp inspection atevery 100 hours.

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

NOTE: Removal of the spinner is necessary, but disassembly of the clamp is notrequired for compliance with this Bulletin.

F. Approval

FAA approval has been obtained on technical data in this publication that affects typedesign.

G. Manpower

Approximately 1.0 man-hour per propeller assembly is required to remove the spinnerand perform a visual inspection of the blade clamps for compliance with this ServiceBulletin.

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




HC-ASB-61-255 of 7

Dec 20/01

Blade Clamp InspectionFigure 1

Using 10 x magnification, visually inspectthe external surfaces around the

circumference of the clamp, focusing inthis area.

2. Material Information

The following material is necessary for clamp replacement (if a crack is discovered in aclamp during visual inspection in accordance with this bulletin). Standard replacementparts 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 PropellerMaintenance Manual 114C (61-10-14) or Hartzell Hydro-Selective PropellerOverhaul Manual 100E (61-10-00), as applicable.

A-321 Screw




Dec 20/01 HC-ASB-61-255 of 7

WARNING: SERIOUS PROPELLER DEFECTS MAY GIVE INDICATIONSBEFORE FAILURE, SUCH AS SUDDEN OR ABNORMAL GREASELEAKAGE OR VIBRATION DURING OPERATION. AN IN-FLIGHTBLADE SEPARATION CAN RESULT IN A CATASTROPHICAIRCRAFT ACCIDENT. IF ABNORMAL GREASE LEAKAGE ORVIBRATION ARE PRESENT, PROPELLER INSPECTION MUST BEPERFORMED BEFORE FURTHER FLIGHT. ADDITIONALLY, REFERTO HARTZELL SERVICE LETTER HC-SL-61-165, WHICHADDRESSES ABNORMAL VIBRATION OR GREASE LEAKAGE.

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

(3) Carefully remove any grease or other matter from the surface that may hindervisual examination of the blade clamps.

(4) Using 10 x magnification, visually inspect the outer surfaces of each blade clampfor cracks. Refer to Figure 1 for a description of the areas on which to focus theinspection.

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

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

(b) Indicate compliance with this Service Bulletin in the propeller logbook andnote when the next clamp inspection is due.

CAUTION: DO NOT FURTHER CLEAN THE CLAMP IF A CRACK ISDISCOVERED.

(6) If a crack is discovered during visual inspection of the blade clamp, remove thepropeller from the aircraft in accordance with Hartzell Propeller Owner's Manual168 (61-00-68) and return it to an authorized propeller repair facility for propelleroverhaul and optical comparator inspection of the blade shanks in accordancewith section 3.B of this Bulletin.




HC-ASB-61-255 of 7

Dec 20/01

B. Propeller Overhaul and Optical Comparator Inspection of Blade Shank

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

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

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

(3) Disassemble each blade clamp. Refer to Disassembly in the Blade ClampOverhaul 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 clampinto a clean, sealed, plastic bag and return it to Hartzell Propeller forevaluation.

(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 BladeClamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02).

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

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

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

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

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

(a) If the blade clamp has been reworked to its maximum repair limit and stillcontains defects, return the clamp to Hartzell Propeller. Refer to theInspection and Repair Criteria section in the Blade Clamp Overhaul chapterof Hartzell Standard Practices Manual 202A (61-01-02).




Dec 20/01 HC-ASB-61-255 of 7

(9) Thoroughly clean the clamp

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

1 35% methanol (>99% pure ), 35% isopropyl alcohol (>99% pure) and30% distilled water.

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

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

CAUTION 1: TO MAINTAIN SOLUTION INTEGRITY, USE A FRESH BATCHOF ALCOHOL SOLUTION FOR EACH CLAMP. THECONTAINER MUST BE CLEANED AFTER EACH USE .

CAUTION 2: KEEP THE ALCOHOL SOLUTION COVERED AT ALL TIMESTO PREVENT EVAPORATION OF THE ALCOHOL.

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

CAUTION: THE CLAMP MUST BE THOROUGHLY WIPED FOLLOWINGTHE ALCOHOL SOLUTION SOAK TO REMOVE ANY TRACESOF FILM THAT ARE LEFT ON THE SURFACE OF THE CLAMP.

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

WARNING: CLEANING AGENT METHYLETHYLKETONE (MEK) ISFLAMMABLE AND TOXIC TO THE SKIN, EYES ANDRESPIRATORY TRACT. SKIN AND EYE PROTECTION AREREQUIRED. AVOID PROLONGED CONTACT. USE IN A WELLVENTILATED AREA.

(d) 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 Replatingchapter 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 BladeClamp Overhaul chapter of Hartzell Standard Practices Manual 202A (61-01-02).




HC-ASB-61-255 of 7

Dec 20/01

(14) Reassemble each blade clamp in accordance with Hartzell Steel Hub PropellerMaintenance Manual 114C (61-10-14), or Hartzell Hydro-Selective PropellerOverhaul Manual 100E (61-10-00), as applicable.

(15) Perform an optical comparator inspection of each blade shank in accordance withAppendix A - Optical Comparator chapter of Hartzell Aluminum Blade OverhaulManual 133C (61-13-33).

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

(16) Reinstall each blade and blade clamp on the propeller assembly in accordancewith Hartzell Steel Hub Propeller Maintenance Manual 114C (61-10-14), orHartzell Hydro-Selective Propeller Overhaul Manual 100E (61-10-00), asapplicable.

(17) Set blade angles and check blade track in accordance with Hartzell Steel HubPropeller Maintenance Manual 114C (61-10-14), or Hartzell Hydro-SelectivePropeller Overhaul Manual 100E (61-10-00), as applicable.

(18) Complete propeller assembly procedures in accordance with Hartzell Steel HubPropeller Maintenance Manual 114C (61-10-14) or Hartzell Hydro-SelectivePropeller 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 therequired overhaul time interval specified in Hartzell Service Letter HC-SL-61-61,contact Hartzell Propeller Product Support Department at (937) 778-4379 forwarranty consideration and instructions.

(2) Any findings discovered as a result of compliance with this Bulletin should bereported to Hartzell Propeller.

Hartzell Propeller Inc. Telephone: 937.778.4379Product Support Department Fax: 937.778.4391One Propeller Place email: [email protected], Ohio 45356 U.S.A.

hartzell propeller inc. alert service bulletinmooney.free.fr/sauvegarde afs/hartzell/sb255.pdf ·...

Documents