Fuel Tank Inerting Harmonization Working Group ARAC Fuel Tank Inerting Harmonization Working Group...

Fuel Tank Inerting Harmonization Working

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ARACARACFuel Tank Inerting Fuel Tank Inerting

Harmonization Working Harmonization Working Group Group Overall Findings and Overall Findings and

Recommendations.Recommendations.Karl S. Beers - FTIHWG Member

Air Liquide - MEDAL

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Third Triennial International Third Triennial International Aircraft Fire and Aircraft Fire and Cabin Safety Cabin Safety

Research ConferenceResearch Conference2424thth October, 2001 October, 2001

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Topics for DiscussionTopics for Discussion

Background Tasking Statement

Working Group Formation

Report Summary Conclusions Recommendations

Some Additional Thoughts…..


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BackgroundBackground FAA initiated rulemaking activity to re-evaluate the industry’s

approach to fuel tank safety following the 1996 fuel tank explosion on a 747 airplane.

In 1998, the FAA tasked ARAC with a six month project to provide specific recommendations and propose regulatory text for rulemaking that would significantly reduce or eliminate the hazards associated with explosive fuel vapors on transport category airplanes. Directed Ventilation Ground Based Inerting

In July 1998, ARAC Fuel Tank Harmonized Working Group recommend that the FAA further investigate the possibility of directed ventilation and ground based inerting of fuel tanks.

The 2001 Working Group’s report is an extension of the 1998 Fuel Tank Working Group’s efforts.


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Tasking StatementTasking Statement The ARAC tasking statement was published in July of 2000.

The tasking statement gave 12 months to draft a report that would provide data needed for the FAA to evaluate the feasibility of implementing regulations that would require eliminating or significantly reducing the development of flammable vapors in fuel tanks.

The tasking statement specified that the report should evaluate the technical feasibility of three specific inerting system concepts and any other inerting concept determined by the Working Group or its individual members, to merit consideration. Ground Based Inerting - From Ground Equipment (GBI) Ground Based Inerting - Using On-Board Equipment (OBGI) On-Board Full Time Inerting Systems (OBIGGS)

- Hybrid Variants of the On-Board Systems


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Tasking Statement (Cont..)Tasking Statement (Cont..) Consider reliable designs with little or no redundancy to minimize

the cost of the design method together with a recommendation for dispatch relief using the master minimum equipment list (MMEL).

Develop regulatory text based on the lowest flammability level that could be achieved by an inerting system design that would meet FAA’s regulatory evaluation requirements.

Evaluate options for implementing these new regulations.

Identify technical limitations for design options considered impractical.

Provide guidance material on analyses and testing for demonstrating certification compliance and instructions for continued airworthiness.


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Working Group FormationWorking Group Formation U.S. and European co-chairman proposed by AIA and AEA

respectively and confirmed by ARAC EX-COM.

FAA Tasking Statement of July 10, 2000 requested from experts interested in participating in the Working Group notify them no later than August 11, 2000.

FAA received numerous replies from which the working group members were selected. The working group members represented a wide variety of organizations.

The Working Group held their first meeting September 25 - 26, 2000.

Task team members were requested from various groups and organizations to provide special expertise, resulting in over 70 task team members from U.S. and Europe.


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08/03/01 Page 1

Fuel Tank Inerting HarmonizationWorking Group Organization

Co-chair Brad MoravecCo-chair Sean O’Callaghan

Integration- Airplane Level Integration- Ad Min & Tech Writing - Project Scheduling

Grd Based Design- Design, Installation, Operation & Maintenance Requirements- Concept Development- Feasibility & Cost/Benefits- Secondary Effects

O/B Design- Design, Installation, Operation & Maintenance Requirements- Concept Development- Feasibility & Cost/Benefits- Secondary Effects

Airport Facility- Design, Installation, Opts & Maint Requirements- Concept Development- Feasibility & Cost/Benefits- Environmental Impact

Airplane Ops &Maintenance

Impact of designs on fleetperformance, operation,maintenance, dispatchreliability, MMEL, etc

Estimating andForecasting

- Economic model and trade study support- Fleet Forecast- Cost reduction proposals

Safety Analysis

- Safety Analysis- Failure Modes and Effects- Fleet history

Rulemaking

- Regulatory Text- Certification Guidance

Working GroupCo-Chairs, AIA, ATA,

AECMA, ALPA, AEA, IAM,FAA, JAA, NADA/F

Industrial Gas Co, API


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Report SummaryReport Summary


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Fleet-wide Flammability Fleet-wide Flammability ExposureExposure

Large Medium Small RegionalRegionalBizTrans Trans Trans TF TP Jet275 pax 195 pax 117 pax 44 pax 31 pax 7 pax

Baseline fuel tank flammability—no inerting system, Percent exposureBaseline fuel tank flammability—no inerting system, Percent exposure Unheated CWTs 6.8 N/A 5.1 2.6 N/A N/AHeated CWT 36.2 23.5 30.6 N/A N/A N/AMain wing tanks 3.6 2.4 3.6 1.6 0.7 1.6

Fuel tank flammability with inerting system, Percent exposureFuel tank flammability with inerting system, Percent exposure GBI Heated CWTs 4.9 2.0 5.2 N/A N/A N/AOBGI Heated CWT 7.0 1.4 5.8 N/A N/A N/AHybrid OBIGGS HCWT 0.9 0.6 0.3 N/A N/A N/AOBIGGS All tanks ~0 ~0 ~0 N/A N/A N/A


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Avoided Accidents With InertingAvoided Accidents With Inerting Avoided accidents are a function of

Current accident rate Fleet flammability exposure of the inerting system Fleet operating hours Expected benefit from SFAR 88 includes an assumption of a 75%

reduction in projected fuel tank explosions due to SFAR 88. This was not agreed by all WG members and if the reduction in fuel tank explosions due to SFAR 88 is assumed to be less than 75%, then the benefits from inerting would be proportionally greater, and vice versa.

Lives saved in post-crash fuel tank fires (initial cause unrelated to the fuel system). 132 for GBI 253 for OBIGGS


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Avoided AccidentsAvoided AccidentsBased on Assumption that SFAR 88 Will Prevent 75% of Future Based on Assumption that SFAR 88 Will Prevent 75% of Future

AccidentsAccidents

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1990 1995 2000 2005 2010 2015 2020Year

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Avoided accidents from SFAR no. 88

Avoided accidents from inerting

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World accidents (pre-SFAR no. 88)Baseline w orld accidents with SFAR no. 88SFAR and onboard, all tanks, <1% flammability exposureSFAR and GBI HCWT, ~2% flammability exposure

Legend:World accidents (pre-SFAR no. 88)Baseline w orld accidents with SFAR no. 88SFAR and onboard, all tanks, <1% flammability exposureSFAR and GBI HCWT, ~2% flammability exposure

Legend:


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Cost-Benefit AnalysisCost-Benefit Analysis The cost-benefit analysis methods that were used are similar

to the FAA’s methods used in regulatory evaluations. The benefits include the monetary value of avoided accidents and

lives saved in post-crash fires. Monetary values are based on FAA and Department of Transportation (DOT) data.

The analysis includes an assumption of a 75% reduction in projected fuel tank explosions due to SFAR no. 88. This was not agreed by all WG members.

Costs and benefits were calculated for the 16 year study period from 2005 to the end of 2020. Present values were calculated by discounting the annual values at 7% to the year 2005.

The total cost for each inerting system includes the cost for modifying in-service, current production, and new type design airplanes.


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Cost Benefit RatioCost Benefit RatioCost-Benefit Analysis

Worldwide ImplementationPresent Value in 2005 $US

Benefit Cost Cost-Benefit

$US billion $US billion RatioGBI (HCWT only) 0.245 10.4 42:1

OBGI (HCWT only) 0.219 11.6 53:1

Hybrid OBIGGS (HCWT only) 0.257 9.9 39:1

OBIGGS (all tanks) 0.441 20.8 47:1


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Report Conclusions Report Conclusions and and

RecommendationsRecommendations


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Report ConclusionsReport Conclusions A goal was set to have the conclusions of this study reached

by Working Group consensus. => NOT ACHEIVED After extensive efforts by many industry experts, the Working

Group did not find a cost-beneficial inerting system concept as defined by the statement of work.

Because this study was unable to identify an inerting design concept that met the FAA’s regulatory evaluation requirements, the FTIHWG concluded that they could not recommend regulatory text based on the flammability level of an inerting system. However, the report does include recommendation of issues for the FAA to consider should the FAA propose performance based regulations based on fuel tank inerting.


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Report RecommendationsReport RecommendationsThe ARAC FTIHWG recommends that the FAA, NASA, and industry expeditiously carry out the following actions:

Investigate means to achieve a practical onboard fuel tank inerting system design concept for future new type design airplanes.

Pursue technological advancements that would decrease the complexity, size, weight, and electrical power requirements, and increased efficiency, reliability, and maintainability of onboard inerting system concepts.

Perform NEA membrane research to improve the efficiency and performance of membranes resulting in lower cost NEA membrane air-separation systems.


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Report RecommendationsReport Recommendations Conduct basic research into high-efficiency, vacuum-jacketed heat exchangers,

and lighter, more efficient cryogenic refrigerators for use in inerting systems.

If a practical fuel tank inerting system is developed, establish a corresponding minimum flammability level and reevaluate and propose regulatory texts and guidance materials accordingly.

Initiate a project to improve and substantiate current flammability and ignitability analyses to better predict when airplane fuel tank ullage mixtures are flammable. This research is needed to support informed design decisions and rulemaking.

Initiate a project to thoroughly document and substantiate the flammability model used in this study.


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Some Additional Thoughts….Some Additional Thoughts….


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Some Additional Thoughts…….Some Additional Thoughts……. The FTIHWG report is the most comprehensive set of data and information ever

gathered in what it would take to inert the fuel tanks of the current and future fleet. It was estimated that over 50,000 man-hours of effort went into the report.

There were some problems with the report identified by the Ex-Com members including the FAA. More detail needed to clarify the “facts and figures” given in the report.

A last minute sensitivity analysis was done and the data was presented at the August 8th Ex-Com meeting. While this data is pertinent to the FTIHWG efforts, it was not documented in the report. Because of the lack of detail on the facts and figures, it may be difficult for anyone to realize the full meaning of the sensitivity analysis.


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More Additional Thoughts…….More Additional Thoughts……. A concern was raised by the Ex-Com that the data was not in the report as to

the cost per ticket for traveling public. At pre-Sept 11 ticket sale levels cost were calculated at levels anywhere from $0.25/seat to

$2.00/seat. If the Inerting Hardware installed on an aircraft were to have dual use, it may

significantly change the cost benefit ratio => more work is need in this area. Using NEA as part of a system used to replace Halon1301 as a cargo bay fire

suppressant. The availability of resources on today’s fleet of commercial aircraft needs to be

evaluated. Would play a significant part in reducing the number of parts in a system and increasing the reliability.

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