Skip Ribbon Commands
Skip to main content
Safety Recommendation Details

Safety Recommendation A-95-082
Details
Synopsis: ABOUT 12:50 P.M. EASTERN DAYLIGHT TIME, ON 8/21/95, AN ATLANTIC SOUTHEAST AIRLINES (ASA), EMBRAER EMB-120, N255AS, OPERATING AS DELTA AIRLINES FLIGHT 7529, MADE AN OFF AIRPORT FORCED LANDING NEAR CARROLLTON, GEORGIA. THE PILOTS REPORTED AN ENGINE FAILURE AS THE FLIGHT WAS CLIMBING THROUGH ABOUT 18,000 FEET. FLIGHT 7529 WAS EN ROUTE FROM ATLANTA, GEORGIA, TO GULFPORT, MISSISSIPPI, AS A SCHEDULED COMMUTER PASSENGER FLIGHT OPERATING UNDER THE PROVISIONS OF TITLE 14 CODE OF FEDERAL REGULATIONS (CFR) PART 135. THERE WERE 26 PASSENGERS, TWO PILOTS & ONE FLIGHT ATTENDANT ABOARD THE FLIGHT. ON 3/20/94, A NORDESTA AIRLINES EMBRAER EMB-120 LOST A MAJOR PORTION OF ONE BLADE OF A HAMILTON STANDARD MODEL 14RF COMPOSITE BLADE WHILE AT CRUISE AT 22,000 FEET OVER BRAZIL. ON 8/3/95, THE MAJOR PORTION OF ANOTHER MODEL 14RF PROPELLER BLADE SEPARATED IN FLIGHT FROM THE RIGHT ENGINE OF A LUXAIR EMB-230, BELGIUM REGISTRATION LX-LGK.
Recommendation: THE NTSB RECOMMENDS THAT THE FAA: CONDUCT A VIBRATION & LOADS SURVEY & ANALYSIS OF THE PROPELLER INSTALLATION ON THE EMBRAER EMB-120 AIRPLANES WITH APPLICABLE HAMILTON STANDARD PROPELLERS THROUGHOUT THE GROUND & FLIGHT OPERATING RANGE OF THE ENGINE WITH SPECIFIC CONSIDERATION FOR THE EFFECTS OF PROPELLER IN-SERVICE WEAR, MAINTENANCE, OR OTHER CHANGES MAY HAVE ON THE RESONANT FREQUENCIES. BASED ON THE FINDINGS, BROADEN THE SURVEY & ANALYSIS TO OTHER INSTALLATIONS AS APPROPRIATE.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: CARROLLTON, GA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA95MA054
Accident Reports: In-flight Loss of Propeller Blade Forced Landing, and Collision with Terrain Atlantic Southeast Airlines, Inc., Flight 529 Embraer EMB-120RT, N256AS
Report #: AAR-96-06
Accident Date: 8/21/1995
Issue Date: 8/25/1995
Date Closed: 8/11/1997
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 8/11/1997
Response: A-95-82 ASKED THE FAA TO CONDUCT A VIBRATION & LOADS SURVEY & ANALYSIS OF THE PROPELLER INSTALLATION ON THE EMBRAER EMB-120 AIRPLANES WITH APPLICABLE HAMILTON STANDARD PROPELLERS THROUGHOUT THE GROUND & FLIGHT OPERATING RANGE OF THE ENGINE WITH SPECIFIC CONSIDERATION FOR THE EFFECTS (THAT) PROPELLER IN-SERVICE WEAR, MAINTENANCE, OR OTHER CHANGES MAY HAVE ON THE RESONANT FREQUENCIES. BASED ON THE FINDING, BROADEN THE SURVEY & ANALYSIS TO OTHER INSTALLATIONS AS APPROPRIATE. BASED ON THE FAA'S ACTIONS, THE BOARD CLASSIFIES A-95-82 "CLOSED--ACCEPTABLE ACTION."

From: FAA
To: NTSB
Date: 4/14/1997
Response: THE FAA STATED THAT IT HAD ISSUED AIRWORTHINESS DIRECTIVE (AD) 95-25-11 12/27/95, TO LIMIT PROPELLER EXPOSURE TO HIGH VIBRATORY STRESSES DURING GROUND OPERATION IN CERTAIN WINDS & RPM CONDITIONS. THE FAA FURTHER STATED THAT IT HAD EVALUATED ADDITIONAL FLIGHT TEST DATA & RECOMMENDATIONS MADE BY THE PROPELLER MANUFACTURER ON THE MODIFICATION OF THE CURRENT OPERATIONAL INSTRUCTION REQUIRED BY AD 95-24-11. THE VARIATION OF THE PROPELLER'S 2P RESONANT FREQUENCY & AIRCRAFT GROUND OPERATING PRCEDURES REQUIRES THE REDUCED EXPOSURE THE REDUCED EXPOSURE TO HIGH VIBRATORY STRESS THAT IS PROVIDED BY THE AD. BASED ON ITS REVIEW, THE FAA DETERMINED THAT THE REQUIREMENT CONTAINED IN AD 95-25-11 ADDRESS THE ISSUE COMPLETELY & NO FURTHER REGULATORY ACTION WILL BE INITIATED.

From: NTSB
To: FAA
Date: 11/15/1996
Response: BASED ON THE FAA'S INTERIM ACTIONS, & THE STATEMENT CONTAINED IN ITS ANNOUNCEMENT OF THE FINAL RULE, THE BOARD CLASSIFIES A-95-82 "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 7/24/1996
Response: HAMILTON STANDARD CONDUCTED A VIBRATION & LOADS SURVEY & ANALYSIS OF THE PROPELLER INSTALLATION ON THE EMBRAER EMB-120 AIRPLANE WITH APPLICABLE HAMILTON STANDARD PROPELLER & SUBMITTED THE RESULTS TO THE FAA. ALTHOUGH THE STRESS SURVEY RESULTS DISCLOSED NO NEW HIGH STRESS CONDITIONS IT DID REVEAL A POSSIBLE SMALL DOWNWARD SHIFT IN THE 2P RESONANT FREQUENCY RELATIVE TO THE ORIGINAL 1983 CERTIFICATION TEST DATA. AS A RESULT, THE FAA ISSUED AIRWORTHINESS DIRECTIVE 95-25-11 ON 12/27/95, TO LIMIT THE RPM RANGE DURING GROUND OPERATIONS AS AN INTERIM ACTION UNTIL FINAL ACTION IS IDENTIFIED.

From: NTSB
To: FAA
Date: 1/16/1996
Response: THE BOARD NOTES THAT THE FAA WILL UNDERTAKE A VIBRATION & FLIGHT STRAIN SURVEY WITH HAMILTON STANDARD & EMBRAER ON THE EMB-120 AIRPLANE TO EVALUATE GROUND & FLIGHT LOADS ON THE PROPELLER INSTALLATION. THE FAA ANTICIPATES THAT THE SURVEY PROGRAM WILL BE COMPLETED BY 2/6/96. PENDING COMPLETION OF THE PROGRAM, THE BOARD CLASSIFIES A-95-82 "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 9/6/1995
Response: THE FAA AGREES WITH THIS RECOMMENDATION & IS DEVELOPING A VIBRATION & FLIGHT STRAIN SURVEY & ANALYSIS IN CONJUCTION WITH HAMILTON STANDARDS & EMBRAER TO EVALUATE LOADS OF THE PROPELLER INSTALLATION OF THE EMBRAER EMB-120. THE PROGRAM WILL INVOLVE TESTS & EVALUATION ON THREE INSTRUMENTED EMB-120 AIRCRAFT. THE OUTFITTING OF THE AIRCRAFT & DEVELOPMENT OF THE DATA WILL REQUIRE 90 DAYS, AFTER WHICH THE FAA WILL EVALUATE THE EFFECTS OF PROPELLER IN-SERVICE WEAR, MAINTENANCE, OR OTHER CHANGES ON THE RESONANT FREQUENCIES. I ANTICIPATE THAT THE PROGRAM WILL BE COMPLETED BY 2/6/96. I WILL KEEP THE BOARD APPRISED OF THE FAA'S PROGRESS ON THIS RECOMMENDATION.