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Monday, January 13, 2003

News Briefs

  • Patent protected. One reader questioned the amount 17-year period Boeing [BA] was protected on its patented fuel tank inerting system (see ASW, Dec. 23, 2002). A double-check reveals the following: the patent was good for 17-years from the April 5, 1983 date of issue by the U.S. Patent Office. The law was changed subsequently to cover a 20-year period from the date on which the patent application was filed. This time period is specified in Section 35, U.S. Code, Part 154, as contained in the November 2002 edition of the Manual of Patent Examining Procedures.

    There would have been no effect had the 20-year coverage been in effect two decades ago. Boeing filed its patent application July 15, 1980, three years before receiving its patent. Thus, the patent would have been in effect for virtually the same period of time, through either April or July 2000, whichever baseline is used.

 

  • Understatement of the year. With the recent spate of airworthiness directives on fuel tank ignition sources, it may be useful to recall that the SFAR-88 effort launched in May 2001 was intended to yield a 75 percent reduction in fuel tank ignition sources (see ASW, Aug. 6, 2002). In a Nov. 4, 2002, letter to the chairman of the Fuel Tank Inerting Harmonizaiton Working Group (FTIHWG), Nicholas Sabatini, Federal Aviaiton Administration head of regulaiton and certificaiton, thanked the committee for its work studying the problem, hailed the FAA's new lightweight inerting system, and, in an attached table, offered this masterfully understated assessment of the SFAR-88 effort: "Industry is finding it difficult to obtain the high estimated benefits they predicted they could achieve with ignition prevention under SFAR-88."

 

  • No comment. Last fall the Federal Aviation Administration (FAA) endorsed a Boeing redesign of the rudder power control unit in the B737, to be installed in the worldwide fleet (see ASW, Oct. 14, 2002). Does the redesign meet the National Transportation Safety Board (NTSB) call for a "reliably redundant" system? The question was posed to FAA administrator Marion Blakey, not only because the question is relevant, but because in her previous position as head of the NTSB, Blakey signed the Jan. 14, 2002, NTSB submission to the docket saying the board had not received sufficient information to determine if the redesign was adequate:

    "Although the Board fully supports modification that will increase rudder system redundancy, it remains unable to determine if the proposed revision to the Boeing 737's rudder system will sufficiently address Safety Recommendation A-99-20 ... The Board is concerned that the design does not provide full independence for the main PCU [power control unit]. It would appear that true redundancy would require two fully independent PCUs. Additionally, although the standby rudder PCU will be automatically activated in certain conditions, such a design is more complex and, therefore, may increase the number of possible failure modes compared to the installation of a third full-time independent PCU."

    By way of additional explanation, the proposed redesign features two servo valves with one PCU. The B757, in comparison, features three fully independent PCUs. Boeing officials have said the B737 redesign is functionally the same as the system on the B757. However, the B757 does not have a shared PCU or a standby that is automatically activated.

    The obvious questions were posed to the FAA: Does Administrator Blakey believe that the Boeing redesign meets the NTSB's call for a reliably redundant system? If so, on what basis?

    In response to repeated queries over the past 12 weeks, FAA officials have said a substantive response would be forthcoming. The latest such assurance was made just last week. Alas, the answer did not arrive by press time, leaving the seminal question of reliable redundancy unanswered for another week. Stay tuned.

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