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Safety Recommendation Details

Safety Recommendation A-00-105
Details
Synopsis: On 7/17/96, about 2031 eastern daylight time, Trans World Airlines, Inc. (TWA) Flight 800, a Boeing 747-131, N93119, crashed into the Atlantic Ocean near East Moriches, New York. TWA Flight 800 was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 121 as a scheduled international passenger flight from John F. Kennedy International Airport (JFK), New York, NY, to Charles de Gaulle International Airport, Paris, France. The flight departed JFK about 2019, with 2 pilots, 2 flight engineers, 14 flight attendants, and 212 passengers on board. All 230 people on board were killed, and the airplane was destroyed. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Examine manufacturers' design practices with regard to bonding of components inside tanks and require changes in those practices, as necessary, to eliminate potential ignition hazards.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: EAST MORICHES, NY, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA96MA070
Accident Reports: In-flight Breakup Over the Atlantic Ocean Trans World Airlines Flight 800, Boeing 747-141, N93119
Report #: AAR-00-03
Accident Date: 7/17/1996
Issue Date: 9/19/2000
Date Closed: 1/13/2011
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Maintenance

Safety Recommendation History
From: NTSB
To: FAA
Date: 1/13/2011
Response: The FAA supplied a list of six separate activities and products that have been released since this recommendation was issued. These activities and products related to bonding inside fuel tanks demonstrate that the FAA completed the first part of this recommendation, to examine manufacturers’ design practices with regard to bonding of components inside fuel tanks. With regard to the second part of the recommendation—to require changes in those practices to eliminate potential ignition hazards—the FAA does not believe that establishing prescriptive bonding requirements is appropriate because the requirements for electrostatic charge mitigation are significantly different than the requirements for lightning protection. Instead, the FAA believes that specific electrical bonding design details should be based on the performance required for a particular feature and electromagnetic environment rather than by FAA airworthiness standards, and each certification applicant will need to define the appropriate electrical bonding for his or her particular design that meets the performance-based standards stated in 14 CFR Part 25. Included in the list of activities were revisions to Part 25.981, Amendment 25-102, concerning fuel tank flammability reduction and the requirements in Part 25.899, Amendment 25-123, together with the guidance in advisory circular (AC) 25.899-1 that specifically address bonding design practices. The FAA has completed the actions recommended; accordingly, Safety Recommendation A-00-105 is classified CLOSED -- ACCEPTABLE ACTION.

From: FAA
To: NTSB
Date: 7/27/2010
Response: Letter Mail Controlled 8/9/2010 11:09:24 AM MC# 2100271 - From J. Randolph Babbitt, Administrator: The FAA completed tasks to address improved airplane bonding and published the following regulations and guidance material (see enclosures); Issued Airworthiness Directive (AD) 98-20-40 (enclosure 3), effective November 4, 1998, for Boeing Model 747-100, -200. -300, SP, and SR series airplanes, requiring shielding and separation of electrical wiring of the fuel quantity indicating system Issued Advisory Circular (AC) 981-1 B, Fuel Tank Ignition Source prevention Guidelines, and AC 25.981-5, Fuel Tank Flammability Reduction Means. These are not provided, as they were superseded by new standards for fuel tank ignition prevention (14 CFR § 25.981, Amendment 25-102, in 2001); Established new regulations for electrical bonding and protection against static electricity (14 CFR § 25.899, Amendment 25-123) with associated guidance in AC 25.899-1, Electrical Bonding and Protection Against Static Electricity. in October 2007 (enclosure 4); Established new regulations for electrical wiring interconnection systems (EWIS), (14 CFR §§ 25.1701-25.1733. Amendment 25-123) and associated guidance (AC 25.1701-1, Certification of Electrical Wiring Interconnection Systems on Transport Category Airplanes) (enclosure 5) in December 2007; and Issued updated guidance (from 2nd bullet) with AC 25.981-2A, Fuel Tank Flammability and Reduction Means (enclosure 6), and AC 981-1C, Fuel Tank Prevention Source Ignition Guidelines (enclosure 7), in September 2008. The FAA investigated the possibility of establishing prescriptive bonding requirements. We found the electrical bonding required for electrostatic charge mitigation is significantly different than the electrical bonding for lightning protection. We determined specific electrical bonding design details should be based on the performance required for a particular feature and electromagnetic environment rather than prescribed by FAA airworthiness standards. We also noted the U.S. Military cancelled their electrical bonding specification MIL-B-5087B for similar reasons. Rather than mandate a particular electrical bonding parameter, each certification applicant will need to define the appropriate electrical bonding for their particular design that meets the performance-based standards in 14 CFR part 25 including the latest regulations noted above.

From: NTSB
To: FAA
Date: 5/17/2002
Response: Issuance of the final rule on April 19, 2001, and of ACs 25.981-1B and 25.981-2 on April 18, 2001, are positive steps in response to this safety recommendation. However, the Safety Board is not aware that any design reviews of the practices regarding bonding of components inside fuel tanks, as required in the final rule, have actually occurred. Nor is the Board aware of any changes to the bonding of components to eliminate potential ignition hazards. Further, the Board is concerned about the amount of latitude that has been given to the parties who will conduct these reviews. The FAA notes that an aviation industry group found that bonding standards vary between manufacturers, and that the group recommended that uniform standards be developed. The FAA stated that with these actions, it believes that the intent of the safety recommendation has been met. Prior to closing this safety recommendation, the Safety Board would like to review the uniform standards that are developed and to verify that the changes resulting from the final rule and the ACs are being implemented in the air transport fleet. Pending the Board's review of this information, Safety Recommendation A-00-105 remains classified OPEN -- ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 5/24/2001
Response: Letter Mail Controlled 05/31/2001 9:08:49 PM MC# 2010450: - From Jane F. Garvey, Administrator: On April 19, 2001, the Federal Aviation Administration (FAA) issued a final rule entitled "Transport Airplane Fuel Tank System Design Review, Flammability Reduction and Maintenance and Inspection Requirements." The final rule requires a design review revalidating the fuel tank system design to ensure that failures will not create ignition sources within the fuel tanks. Manufacturers are also required to design specific programs for the maintenance and inspection of the tanks to ensure the continued safety of fuel tank systems. I have enclosed a copy of the final rule for the Board's information. The design review will include examination of manufacturers' design practices with regard to bonding of components inside fuel tanks. The required maintenance and inspection programs will include actions necessary to ensure that adequate bonding of components inside fuel tanks are maintained as part of the continued safety program. On April 18, 2001, the FAA issued Advisory Circular (AC) 25.981-lB, Fuel Tank Ignition Source Prevention Guidelines, and AC 25.981-2, Fuel Tank Flammability Minimization. I have enclosed a copy of these AC's for the Board's information. In addition to the fuel bonding issue of this safety recommendation, the international aviation industry's Aircraft Fuel System Safety Program group issued a report entitled "Aircraft Fuel System Safety Program" on August 4, 2000. The report summarized the results of the assessment of the in-service fleet. The report included the following recommendation regarding fuel tank component bonding standards: ??While the Aircraft Fuel System Safety Program inspection has confirmed that manufacturers' standards for fuel tank bonding are effective and robust in service, it also highlighted the fact that these standards vary. Therefore, in addition to the bonding inspections noted above (in the report), industry recommends that groups like the Society of Automotive Engineers or the Institute of Electrical and Electronics Engineers develop uniform standards or processes for fuel tank bonding requirements and test techniques and bonding jumpers used in fuel tanks. The FAA agrees that a coordinated industry standard for fuel tank component bonding could standardize bonding methods used by various aircraft manufactures and, therefore, reduce the resources needed to review individual manufacturers' bonding practices. However, such a standard is not required to review fuel tank component bonding under the final rule. Manufacturers may use different bonding standards provided each design meets the minimum standards established by the Federal Aviation Regulations. Consequently, the FAA will support industry's effort to create a new fuel tank component standard, but such a standard is not required to support the design review that would be required by the final rule or address Safety Recommendation A-00-105. I believe that the FM has met the full intent of this safety recommendation, and I consider the FAA's action to be completed.

From: NTSB
To: FAA
Date: 12/5/2000
Response: FAA and Safety Board staff met on 10/17/00, to discuss these recommendations. The meeting initiated a dialogue that will lead to mutually agreeable actions for each of these recommendations. The FAA anticipates providing the board with a complete response to these recommendations by 1/31/01. Pending submission of that complete response, A-00-105 through -108 are classified OPEN – ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 10/12/2000
Response: Letter Mail Controlled 10/16/2000 3:58:40 PM MC# 2001542 - From Jane F. Garvey, Administrator: Your staff has agreed to meet with FAA technical specialists on 10/17/00, to discuss these recommendations. This meeting will offer an opportunity to begin a dialogue between our agencies that can lead to mutually agreeable actions for each of these recommendations. After this meeting, the FAA will have a better understanding of the intent of these recommendations and be in a better position to provide detailed response to these recommendations. We anticipate providing the Board with a complete response to these recommendations by 1/31/01.