AD T95-18-51

T95-18-51 HAMILTON STANDARD: TELEGRAPHIC AD ISSUED ON AUGUST 25, 1995. DOCKET 95-ANE-48.

APPLICABILITY: HAMILTON STANDARD MODELS 14RF-9, 14RF-19, 14RF-21, AND 14SF-5, 14SF-7, 14SF-11, 14SFL11, 14SF-15, 14SF-17, 14SF-19, AND 14SF-23; AND HAMILTON STANDARD/BRITISH AEROSPACE 6/5500/F PROPELLERS INSTALLED ON BUT NOT LIMITED TO EMBRAER EMB-120 AND EMB 120-RT; SAAB-SCANIA SF 340B; AEROSPATIALE ATR42-100, ATR42-300, ATR42-320, ATR72; DEHAVILLAND DHC-8-100 SERIES, DHC-8-300 SERIES; CONSTRUCCIONES AERONAUTICAS SA (CASA) CN-235 SERIES AND CN-235-100; CANADAIR CL-215T AND CL-415; AND BRITISH AEROSPACE ATP AIRPLANES. NOTE: THIS AD APPLIES TO EACH PROPELLER IDENTIFIED IN THE PRECEDING APPLICABILITY PROVISION, REGARDLESS OF WHETHER IT HAS BEEN MODIFIED, ALTERED, OR REPAIRED IN THE AREA SUBJECT TO THE REQUIREMENTS OF THIS AD. FOR PROPELLERS THAT HAVE BEEN MODIFIED, ALTERED, OR REPAIRED SO THAT THE PERFORMANCE OF THE REQUIREMENTS OF THIS AD IS AFFECTED, THE OWNER/OPERATOR MUST USE THE AUTHORITY PROVIDED IN PARAGRAPH (E) TO REQUEST APPROVAL FROM THE FAA. THIS APPROVAL MAY ADDRESS EITHER NO ACTION, IF THE CURRENT CONFIGURATION ELIMINATES THE UNSAFE CONDITION, OR DIFFERENT ACTIONS NECESSARY TO ADDRESS THE UNSAFE CONDITION DESCRIBED IN THIS AD. SUCH A REQUEST SHOULD INCLUDE AN ASSESSMENT OF THE EFFECT OF THE CHANGED CONFIGURATION ON THE UNSAFE CONDITION ADDRESSED BY THIS AD. IN NO CASE DOES THE PRESENCE OF ANY MODIFICATION, ALTERATION, OR REPAIR REMOVE ANY PROPELLER FROM THE APPLICABILITY OF THIS AD.

COMPLIANCE: REQUIRED AS INDICATED, UNLESS ACCOMPLISHED PREVIOUSLY.

TO PREVENT SEPARATION OF A PROPELLER BLADE DUE TO CRACKS INITIATING IN THE BLADE TAPER BORE, THAT CAN RESULT IN AIRCRAFT DAMAGE, AND POSSIBLE LOSS OF AIRCRAFT CONTROL, ACCOMPLISH THE FOLLOWING:

(A) FOR HAMILTON STANDARD 14RF-9 PROPELLER BLADES, INSTALLED ON EMBRAER EMB-120 SERIES AIRCRAFT, WITHIN THE NEXT 10 FLIGHT CYCLES AFTER THE EFFECTIVE DATE OF THIS AD, REMOVE FROM SERVICE PROPELLER BLADES THAT HAVE BEEN ULTRASONICALLY SHEAR WAVE INSPECTED IN ACCORDANCE WITH AD 94-09-06 OR AD 95-05-03, REMOVED FROM SERVICE DUE TO CRACK INDICATIONS, AND SUBSEQUENTLY REWORKED AND RETURNED TO SERVICE. THESE PROPELLER BLADES INCLUDE, BUT ARE NOT LIMITED TO, THE FOLLOWING SERIAL NUMBERS:

847598, 851646, 852085, 852561, 853151, 854530, 854535, 854838, 855014, 855042, 855196, 855859, 857375, 858696, 859824, 860589, 867590, 876707, 880245

(B) FOR HAMILTON STANDARD MODELS 14RF-19, 14RF-21, AND 14SF-5, 14SF-7, 14SF-11, 14SFL11, 14SF-15, 14SF-17, 14SF-19, AND 14SF-23; AND HAMILTON STANDARD/BRITISH AEROSPACE 6/5500/F PROPELLER BLADES, INSTALLED ON AIRCRAFT OTHER THAN EMBRAER EMB-120 AIRCRAFT, WITHIN THE NEXT 10 FLIGHT CYCLES AFTER THE EFFECTIVE DATE OF THIS AD, AND THEREAFTER AT INTERVALS NOT TO EXCEED 1,250 FLIGHT CYCLES SINCE LAST INSPECTION, PERFORM AN ULTRASONIC SHEAR WAVE INSPECTION FOR CRACKS IN THE BLADE TAPER BORE OF PROPELLER BLADES THAT HAVE BEEN ULTRASONICALLY INSPECTED IN ACCORDANCE WITH AD 94-09-06 OR AD 95-05-03, REMOVED FROM SERVICE DUE TO CRACK INDICATIONS, AND SUBSEQUENTLY REWORKED AND RETURNED TO SERVICE. PERFORM THE ULTRASONIC SHEAR WAVE INSPECTION IN ACCORDANCE WITH THE ACCOMPLISHMENT INSTRUCTIONS OF THE FOLLOWING HAMILTON STANDARD ALERT SERVICE BULLETINS (ASB'S), AS APPLICABLE: NO. 14RF-21-61-A68, DATED AUGUST 25, 1995; NO. 14SF-61-A88, DATED AUGUST 25, 1995; NO. 14RF-19-61-A49, DATED AUGUST 25, 1995; NO. 6/5500/F-61-A36, DATED AUGUST 25, 1995. REMOVE CRACKED PROPELLER BLADES FROM SERVICE AND REPLACE WITH SERVICEABLE PARTS.

(C) PROPELLER BLADES REMOVED FROM SERVICE IN ACCORDANCE WITH THIS AD MAY NOT BE RETURNED TO SERVICE.

(D) FOR THE PURPOSE OF THIS AD, A FLIGHT CYCLE IS DEFINED AS ONE TAKEOFF AND THE NEXT LANDING OF AN AIRCRAFT.

(E) AN ALTERNATIVE METHOD OF COMPLIANCE OR ADJUSTMENT OF THE INITIAL COMPLIANCE TIME THAT PROVIDES AN ACCEPTABLE LEVEL OF SAFETY MAY BE USED IF APPROVED BY THE MANAGER, BOSTON AIRCRAFT CERTIFICATION OFFICE. THE REQUEST SHOULD BE FORWARDED THROUGH AN APPROPRIATE FAA PRINCIPAL MAINTENANCE INSPECTOR, WHO MAY ADD COMMENTS AND THEN SEND IT TO THE MANAGER, BOSTON AIRCRAFT CERTIFICATION OFFICE. NOTE: INFORMATION CONCERNING THE EXISTENCE OF APPROVED ALTERNATIVE METHODS OF COMPLIANCE WITH THIS AIRWORTHINESS DIRECTIVE, IF ANY, MAY BE OBTAINED FROM THE BOSTON AIRCRAFT CERTIFICATION OFFICE.

(F) SPECIAL FLIGHT PERMITS MAY BE ISSUED IN ACCORDANCE WITH SECTIONS 21.197 AND 21.199 OF THE FEDERAL AVIATION REGULATIONS (14 CFR 21.197 AND 21.199) TO OPERATE THE AIRCRAFT TO A LOCATION WHERE THE REQUIREMENTS OF THIS AD CAN BE ACCOMPLISHED.

(G) COPIES OF THE APPLICABLE SERVICE INFORMATION MAY BE OBTAINED FROM HAMILTON STANDARD, ONE HAMILTON ROAD, WINDSOR LOCKS, CT 06096-1010; TELEPHONE (203) 654-3610. THIS INFORMATION MAY BE EXAMINED AT THE FAA, NEW ENGLAND REGION, OFFICE OF THE ASSISTANT CHIEF COUNSEL, 12 NEW ENGLAND EXECUTIVE PARK, BURLINGTON, MA.

(H) TELEGRAPHIC AD T95-18-51, ISSUED ONAUGUST 25, 1995, BECOMES EFFECTIVE UPON RECEIPT.

EMERGENCY DISTRIBUTION BY TELEGRAM IS REQUIRED.

TRANSMITTED AS FOLLOWS IS TELEGRAPHIC AIRWORTHINESS DIRECTIVE T95-18-51 FOR IMMEDIATE TRANSMITTAL TO ALL OWNERS AND OPERATORS OF HAMILTON STANDARD MODELS 14RF-9, 14RF-19, 14RF-21, AND 14SF-5, 14SF-7, 14SF-11, 14SFL11, 14SF-15, 14SF-17, 14SF-19, AND 14SF-23; AND HAMILTON STANDARD/BRITISH AEROSPACE 6/5500/F PROPELLERS INSTALLED ON BUT NOT LIMITED TO EMBRAER EMB-120 AND EMB 120-RT; SAAB-SCANIA SF 340B; AEROSPATIALE ATR42-100, ATR42-300, ATR42-320, ATR72; DEHAVILLAND DHC-8-100 SERIES, DHC-8-300 SERIES; CONSTRUCCIONES AERONAUTICAS SA (CASA) CN-235 SERIES AND CN-235-100; CANADAIR CL-215T AND CL-415; AND BRITISH AEROSPACE ATP AIRPLANES.

THIS TELEGRAPHIC AIRWORTHINESS DIRECTIVE (AD) IS PROMPTED BY REPORT OF A HAMILTON STANDARD 14RF-9 PROPELLER BLADE INSTALLED ON AN EMBRAER EMB-120 AIRCRAFT THAT SEPARATED IN FLIGHT. THE PRELIMINARY INVESTIGATION HAS REVEALED THAT THIS PROPELLER BLADE TAPER BORE HAD BEEN ULTRASONICALLY INSPECTED FOR CRACKS IN ACCORDANCE WITH AIRWORTHINESS DIRECTIVE (AD) 94-09-06, AMENDMENT 39-8894 (59 FR 19127, APRIL 22, 1994). THAT AD WAS SUBSEQUENTLY SUPERSEDED BY AD 95-05-03, AMENDMENT 39-9170 (60 FR 12663, MARCH 8, 1995). THAT INSPECTION DETERMINED THAT THE SUBJECT PROPELLER BLADE HAD CRACK INDICATIONS AND WAS REMOVED FROM SERVICE. THE PROPELLER WAS SUBSEQUENTLY REWORKED IN ACCORDANCE WITH APPROVED DATA AND RETURNED TO SERVICE. AFTER THE PROPELLER WAS REWORKED IN ACCORDANCE WITH APPROVED DATA, DEFECTS REMAINED THAT WERE UNDETECTABLE USING CURRENT METHODS. IN ADDITION, SERVICE EXPERIENCE SUGGESTS THE POSSIBILITY THAT PROPELLER BLADES INSTALLED ON EMBRAER EMB-120 SERIES AIRCRAFT MAY EXPERIENCE HIGHER STRESS THAN SIMILAR PROPELLER BLADES INSTALLED ON OTHER AIRCRAFT. THIS CONDITION, IF NOT CORRECTED, COULD RESULT IN SEPARATION OF A PROPELLER BLADE DUE TO CRACKS INITIATING IN THE BLADE TAPER BORE, THAT CAN RESULT IN AIRCRAFT DAMAGE, AND POSSIBLE LOSS OF AIRCRAFT CONTROL.

THE FAA HAS REVIEWED AND APPROVED THE TECHNICAL CONTENTS OF HAMILTON STANDARD ALERT SERVICE BULLETINS (ASB'S): NO. 14RF-21-61-A68, DATED AUGUST 25, 1995; NO. 14SF-61-A88, DATED AUGUST 25, 1995; NO. 14RF-19-61-A49, DATED AUGUST 25, 1995; NO. 6/5500/F-61-A36, DATED AUGUST 25, 1995.

SINCE AN UNSAFE CONDITION HAS BEEN IDENTIFIED THAT IS LIKELY TO EXIST OR DEVELOP ON OTHER PROPELLERS OF THIS SAME TYPE DESIGN, THIS TELEGRAPHIC AD WILL REQUIRE: REMOVAL FROM SERVICE OF CERTAIN HAMILTON STANDARD 14RF-9 PROPELLER BLADES INSTALLED ON EMBRAER EMB-120 SERIES AIRCRAFT; AND AN INITIAL AND REPETITIVE ULTRASONIC SHEAR WAVE INSPECTIONS FOR CRACKS ON CERTAIN REWORKED PROPELLER BLADES INSTALLED ON AIRCRAFT OTHER THAN THE EMBRAER EMB-120 SERIES. PROPELLER BLADES REMOVED FROM SERVICE IN ACCORDANCE WITH THIS AD MAY NOT BE RETURNED TO SERVICE. THE ACTIONS ARE REQUIRED TO BE ACCOMPLISHED IN ACCORDANCE WITH THE ASB'S DESCRIBED PREVIOUSLY.

THIS RULE IS ISSUED UNDER 49 U.S.C. SECTION 44701 (FORMERLY SECTION 601 OF THEFEDERAL AVIATION ACT OF 1958) PURSUANT TO THE AUTHORITY DELEGATED TO ME BY THE ADMINISTRATOR, AND IS EFFECTIVE IMMEDIATELY UPON RECEIPT OF THIS TELEGRAM: