An FAA airworthiness directive (AD) issued in October could ground more than 70 narrow-body bizliners worldwide that are equipped with auxiliary fuel systems designed to give the aircraft additional range.
Affected are Boeing’s 727; 737-200, -300, -400 and -500 models; 737-800 and -900 (the BBJ and BBJ2, respectively); 757-200 and 767-200; Bombardier’s CRJ100/ 440; and the McDonnell Douglas DC-8-62, DC-9-33F, MD-81, MD-82, MD-83 and MD-87. The FAA estimates that the AD affects about 59 U.S.-registered aircraft.
The AD stems from the NTSB’s findings following the crash of a TWA Boeing 747-100 in 1996 that killed all 230 people on board. The Safety Board concluded that even though the exact origin of the spark that ignited the highly volatile vapor in the centerline fuel tank was unknown, it was probably a short-circuit outside the tank that allowed a high-voltage charge to travel into the tank through the wire of the fuel quantity indication system.
The FAA subsequently issued rules regarding fuel tank safety for new aircraft, along with Special Federal Aviation Regulation (SFAR) 88, Parts 1 and 2, requiring STC holders for existing aircraft to “substantiate that their fuel tank systems can prevent ignition sources in the fuel tanks.” The rule eventually included providers of auxiliary fuel systems, tanks and equipment used to increase the range of airliners converted to executive use.
The agency then issued an AD requiring that the affected auxiliary fuel systems either be modified to eliminate potential ignition sources or be deactivated by Dec. 16, 2009. To do neither would result in grounding of the aircraft. The FAA estimates the cost to deactivate the auxiliary fuel systems at $3,600 per aircraft. The previous SFAR 88 Part 1 and Part 2 requirements are part of the AD.
Mod Approvals Coming
Among the manufacturers of affected auxiliary fuel tanks are DeCrane subsidiary PATS of Georgetown, Del., Canadian aviation services provider Flying Colours of Peterborough, Ontario and Elisen Technologies of Dorval, Quebec.
According to a PATS spokes-man, the FAA has yet to approve any alternate means of compliance through system modification; however, PATS has developed modification kits, the first of which has been available for the BBJ series and 737-300 since last year. The kits will eventually be certified for all aircraft fitted with the PATS auxiliary fuel systems, including Boeing’s 737 series and BBJs, the Boeing 757, Boeing 767 and the CRJ200.
Flying Colours said it has only one CRJ200 in service with its auxiliary fuel system. The airplane has received Transport Canada certification and is in service with an Asian operator. According to director of marketing and sales Sean Gillespie, the company was hoping for FAA certification this month.
Elisen Technologies is producing an auxiliary fuel system for a CRJ200 for subsidiary MJet. The work was scheduled for completion late this year, with Transport Canada certification of the aircraft and auxiliary fuel system anticipated in next year’s first quarter. According to Elisen co-chairman Taif Rahman, the system will comply with the latest FAA AD and Elisen will apply for that agency’s approval.