737.1 Cold Soaked Fuel Frost Terry Sheehan 737NG Procedures Manager Boeing Commercial Airplanes May 2004 The Boeing Company 737.2 Background • Cold Soak Fuel Frost (CSFF) continues to be a concern for many 737NG operators – High frequency of occurrence – High recurring cost to detect and remove CSFF – High frequency of occurrence at stations that do not have deicing equipment – Negative impact on the value of fuel tankering The Boeing Company 737.3 Background • System solutions are not viable – Studies of many concepts in progress for four years – No viable business case for any technically feasible concept The Boeing Company 737.4 Background • AFM requires use of all center tank fuel prior to the use of main tank fuel • AD 2002-19-52 and AD 2002-24-51 provide relief from the AFM limitation to eliminate dry running of center tank fuel pumps – Unintentional benefit - reduced exposure to CSFF • Several operators have devised fuel usage procedures based on the AD to prevent exposure to CSFF – AD procedures will be eliminated with termination of the AD The Boeing Company 737.5 Typiicall CSFF Formattiion The Boeing Company 737.6 Regullattory Requiirementtss • CSFF removal is an FAA regulatory requirement (14 CFR 121.629(b)) – “No person may take off an aircraft when frost, ice, or snow is adhering to the wings, control surfaces, propellers, engine inlets, or other critical surfaces of the aircraft…….Takeoffs with frost under the wing in the area of the fuel tanks may be authorized by the Administrator” FAA The Boeing Company 737.7 Regullattory Requiirementtss • JAA/EASA also addresses cold soaked fuel frost in JAR-OPS 1.345, Ice and Other Contaminants – “A commander shall not commence take-off unless the external surfaces are clear of any deposit which might adversely affect the performance and/or controllability of the aeroplane except as permitted in the Aeroplane Flight Manual” JJAA The Boeing Company 737.8 Wiing Aerodynamiicss wiitth CSFF • Wind tunnel tests completed in December 2002 – CSFF was modeled with “grit” applied to affected wing regions • Flight demonstration completed in August 2003 with CSFF on upper wing surface • Results – For wing fuel load up to 83%, no degradation in handling qualities (pitch, roll) – Impact on aerodynamic performance not significant – No impact on certified performance The Boeing Company 737.9 Propossed Operattiionall Proceduress • Takeoff with light coatings of cold-soaked fuel frost on upper wing surfaces is permissible, provided the following are met: – Frost on the upper surface is less than 1/16 inch (1.5 mm) in thickness – The extent of the frost is similar on both wings – The frost is on or between the black lines defining the permissible cold-soaked fuel frost area with no ice or frost on the leading edges or control surfaces – The outside air temperature is above freezing – There is no precipitation or visible moisture The Boeing Company 737.10 CSFF Permiissssiiblle Area The Boeing Company 737.11 New Suppllementtary Proceduress The Boeing Company 737.12 Deplloymentt off CSFF • Boeing will incorporate CSFF permissible area in production starting with Line Number 1538 in July 2004, as a standard feature – Lines on wing upper surface – Manual updates to support operations will include Airplane Flight Manual, Airplane Maintenance Manual, and Flight Crew Operations Manual • Retrofit will be available per Boeing Service Bulletin 737-11-1125 The Boeing Company 737.13 Deplloymentt off CSFF • Boeing will work with each affected operator and the respective regulatory agency to obtain regulatory approval and to implement procedures – FAA customers will require exemption – Boeing working with FAA Flight Standards – Boeing will assist operators with their exemption requests – FAA working toward a rule change in the longer term – JAA/EASA rules do not explicitly require exemption – Boeing will work directly with operators
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发表于 2010-4-5 01:21:31
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发表于 2010-6-11 00:26:35