Air Safety Week

8.19.02

More maintenance mayhem


       With additional research, the toll in aircraft and people from maintenance errors, in whole or as a contributing factor, continues to mount from our initial estimate (see ASW, Aug. 12). The toll of more than 3,100 killed is now some 30 percent higher than the initial estimate of 2,400 deaths.

       According to Airclaims, a UK-based aviation consulting firm, the insurance losses amount to $3.5 billion, or about 16 percent higher than the initial estimate of $3.0 billion. The period of interest basically spans the jet age. The additions, fatal and otherwise, are listed below as further evidence of the range of possibility for error. These cases also provide additional justification for maintenance error management systems (MEMS):

       * Dec. 4, 2001. B767 (operator unknown). Improperly latched pylon fairing blew off. Similar to Nov. 1996 incident involving an A320.

       * Feb. 24, 1999. China Southwest Airlines Tu-154. Sudden pitch-down and crash on approach to Wenzhou, China. Probable cause: self-locking nut - not the castle nut with cotter pin as specified - installed in bolt for connection between pull rod and bellcrank in elevator control system. Nut screwed off, resulting in loss of bolt and subsequent loss of pitch control. Circumstance similar to and prefigured Feb. 16, 2000, crash of Emery DC-8 freighter. Toll: 61 passengers [pax] and crew killed.

       *  July 30, 1998. Alliance Air D228. Pitch-up, engine fire and crash in India. Probable cause attributed by Indian authorities to "poor aircraft maintenance practices." More specifically, uncommanded movement of horizontal stabilizer "due to partial detachment of its actuator forward bearing support fitting due to non-installation of required hi-lok fasteners." Killed: 9 pax and crew, 2 on ground.

       *  Nov. 6, 1997. Royal Air Force BAe146 (one of three aircraft used to transport the Royal Family). Emergency landing at London Stansted Airport. Loss of oil from all four engines of aircraft. Magnetic chip-detector plugs (MCDPs) had been installed without oil seals ('O' rings). Supervisor with no engine maintenance training performed the work himself, asked a technician to sign the job card as doing the work, and then signed as the person who supervised the
work. No injuries.

       * March 18, 1997. Stavropol An-24. Massive corrosion in fuselage caused tail section to separate during cruise at FL197. Probable cause attributed to "superficial inspection of aircraft carried out without use of monitoring instruments, subsequent unjustified decision to extend time between overhauls, failure to detect corrosion in hard-to-reach areas, failure to carry out prescribed anti-corrosion measures during overhaul." Toll: 50 pax and crew killed.

       *  Jan. 21, 1997. A300-600F (operator unknown). As aircraft climbed from Hawarden Airport Runway 05, wheel well lining panel fell off. Determined by UK AAIB [Air Accidents Investigation Branch] to have been improperly attached after maintenance. No injuries.

       * Feb. 2, 1995. VASP B737. Emergency return to Sao Paulo, overran runway followed by collapse of nose and right main landing gear. No. 3 leading edge flap actuator fractured due to corrosion. Some 1981 Boeing service bulletins not complied with, including one calling for replacement of the aluminum leading edge actuator with a steel one. No injuries. Aircraft hulk used as fire trainer.

       * April 26, 1994. China Airlines A300B4. Crashed at Nagoya with 'go around' mode still engaged and horizontal stabilizer in full nose-up position. In addition to crew mishandling, investigators noted SB A300-22-6021 had not been incorporated into the aircraft, and cited this oversight as a factor: "The manufacturer did not categorize the SB as 'Mandatory' ... the airworthiness authority did not issue promptly an airworthiness directive pertaining to implementation of the SB." Toll: 264 fatalities.

       * Aug. 10, 1986. American Trans Air DC-10-40. Company maintenance personnel placed damaged passenger seatbacks (incorporating chemical oxygen generators) in forward cargo hold. Maintenance technician improperly handled generator by its hose, causing it to ignite. Raging fire burned through cabin floor and destroyed aircraft. No injuries.

       * March 3, 1974. THY [Turk Hava Yollari] DC-10-10. Crash after takeoff from Paris Orly Airport following blowout of aft cargo door on left side. Defective closing of door resulted from a combination of factors, including incomplete application of Service Bulletin SB 52-37, incorrect modifications and adjustments which led to failure of lock pins to fully engage and switching off of warning light in cockpit before the door was locked. Toll: 346 pax and crew killed.

       Sources: NTSB, UK AAIB, UK CAA, Aviation Safety Network, Airclaims