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Safety Recommendation Details

Safety Recommendation A-72-058
Details
Synopsis: DURING THE NATIONAL TRANSPORTATION SAFETY BOARD'S INVESTIGATION OF AN IN-FLIGHT TURBULENCE ACCIDENT INVOLVING A NATIONAL AIRLINES BOEING MODEL B-747 AIRCRAFT NEAR GRAND ISLE, LOUISIANA, ON JANUARY 4, 1972, WE DETERMINED THAT THE SUNDSTRAND DATA CONTROL ARINC 542 FLIGHT DATA RECORDER INSTALLED ON THE SUBJECT AIRCRAFT WAS NOT RECORDING VERTICAL ACCELERATION PROPERLY. BENCH CHECKS AND CALIBRATION TESTS OF THE SUBJECT ACCELEROMETER TRANSDUCER AND FLIGHTRECORDER SHOWED NO ABNORMALITIES.
Recommendation: REEVALUATE THE INSTALLATION OF SUNDSTRAND RECORDERS ON B-747 AIRCRAFT.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Lake Charles, LA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: LAX72AL043
Accident Reports: National Airlines, Inc., Boeing 747-135, N77722
Report #: AAR-72-21
Accident Date: 1/4/1972
Issue Date: 4/19/1972
Date Closed: 9/1/1972
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 8/7/1972
Response: Closed--acceptable action.

From: FAA
To: NTSB
Date: 7/20/1972
Response: Sundstrand tested a number of flight recorders in accordance with the requirements of tso-c51a, paragraph 6.2 and found that all units tested were in compliance with those requirements. It was found, however, that a few of the units tested were marginal as to meeting the ten percent accuracy criteria of paragraph 6.2 at g levels above 4 g's, and at frequency of 2 cps. Even though these units meet the minimum requirements as to acceleration recording, sundstrand has decided to make a minor modi- fication consisting of a resistor change to increase the sensitivity of their flight recorders. This change will be described in a service bulletin.

From: FAA
To: NTSB
Date: 5/19/1972
Response: 5/19/72 - THE FAA RESPONDED STATING THEY ARE AWARE OF THE SITUATION OUTLINED BY THE BOARD WHEREIN THE VERTICAL ACCELERATION PARAMETER DID NOT APPEAR TO BE RECORDING PROPERLY ON THE SUNDSTRAND FDR. THEY HAVE BEEN WORKING WITH BOEING ON THE SUNDSTRAND BUT HAVE NOT YET BEEN ABLE TO DETERMINE IF THIS IS SOLELY A RECORDER PROBLEM, AN AIRCRAFT RECORDER SYSTEM INSTALLATION PROBLEM OR A COMBINATION OF BOTH. THE BOARD WILL BE ADVISED OF CORRECTIVE ACTIONS TAKEN. 7/20/72 - FURTHER TO THEIR LETTER OF 5/19/72, THE FAA STATED THAT SUNDSTRAND HAD TESTED A NUMBER OF FLIGHT RECORDERS. ALL MEET THE MINIMUM REQUIREMENTS OF TSO-C51A. HOWEVER, SOME TESTED WERE MARGINAL. MODIFICATIONS CONSISTING OF RESISTOR CHANGES WILL BE MADE TO INCREASE SENSITIVITY OF THE FLIGHT RECORDERS. THIS CHANGE WILL BEDESCRIBED IN A SERVICE BULLETIN. EVALUATION WAS ALSO MADE OF THE RECORDERS INSTALLATION IN THE B-747. APPROXIMATELY 35 TAPES WERE EXAMINED FROM FLIGHT TESTS WHERE A NUMBER OF MANEUVERS WERE PERFORMED. IN ALL CASES, THE ACCELERATION TRACES EXHIBITED THE INTELLIGENCE EXPECTED FROM SUCH MANUEVERS. IT IS THE FAA'S BELIEF THAT THE FLIGHT RECORDER INSTALLATION IN THE NAL 747 WAS NOT FUNCTIONING CORRECTLY. ALL RECORDERS IN 747'S ARE NOW REQUIRED TO BE RETROFITTED WITH EXPANDED PARAMETERS NOT LATER THAN SEPTEMBER 18, 1973.