NTSB Urges Inspections Of Certain Airbus A300 Rudders

NTSB PRESS RELEASE

NTSB URGES INSPECTIONS OF CERTAIN AIRBUS A300 RUDDERS

NTSB PRESS RELEASE / SAFETY RECOMMENDATION

 

National Transportation Safety Board

Washington, DC 20594

FOR IMMEDIATE RELEASE: March 24, 2006

SB-06-16

 

NTSB URGES INSPECTIONS OF CERTAIN AIRBUS A300 RUDDERS(Safety Recommendation A-06-27 and -28)

Washington, D.C. – The National Transportation Safety Boardtoday urged the Federal Aviation Administration to orderinspections of the inner skin of the composite ruddersurfaces of certain Airbus A-300 series airplanes. The safety recommendations (one of which is classifiedas urgent by the Safety Board) address a safety issueidentified during the investigation of damage found duringan inspection of a rudder from a Federal Express A300-600airplane. The Board noted that this incident might haveapplicability to a more serious rudder separation thatoccurred last year. “The Board believes that this urgent recommendation,if acted upon quickly, will go a long way to prevent acatastrophic failure of the rudder,” NTSB Acting ChairmanMark V. Rosenker said. On March 6, 2005, an Airbus A310-300, operated by AirTransat as flight 961, experienced an in-flight separationof its rudder shortly after departure from Juan G. GomezInternational Airport in Varadero, Cuba. The flightreturned to Varadero, where it landed uneventfully. Uponlanding, the crew discovered that most of the airplane’srudder had separated in flight with only the bottom closingrib and the spar between the rib and the hydraulic actuatorsremaining. Following the Air Transat accident, which is beinginvestigated by Canada with the assistance of the NTSB,Airbus issued a mandatory All Operator Telex (AOT) A300-55A6035 specifying a one-time rudder inspection for all A-300 series airplanes equipped with premodification 8827 or40904 rudders. On March 28, 2005, the FAA issuedAirworthiness Directive (AD) 2005-07, requiring operators toperform the inspections specified in the AOT. AmericanAirlines and Federal Express (the only U.S. operators ofthese airplanes) complied with the AD. On November 27, 2005, the rudder on an Airbus A300-600airplane operated by Federal Express was damaged duringroutine maintenance. To assess the extent of the damage,the rudder was shipped to the manufacturer’s facility andexamined. In addition to the damage that occurred duringmaintenance, the examination found a substantial area ofdisbonding between the inner skin of the composite ruddersurface and the honeycomb core, which is located between twocomposite skins. Further examination of the disbonded area revealedtraces of hydraulic fluid. Hydraulic fluid contaminationbetween the honeycomb skin and the fiberglass composite skincan lead to progressive disbonding, which compromises thestrength of the rudder. Tests on the damaged rudder alsorevealed that disbonding damage could spread during flight. The investigation found that the areas specified inthe AOT did not include the areas in which the disbonds werefound on the incident rudder. Further, it was determinedthat tap tests on the external surfaces of the rudder likelywould not have disclosed the disbonding of an internalsurface. On March 2, 2006 Airbus issued AOTs notifyingoperators of applicable A300 series airplanes that largedisbonds between the rudder’s inner skin and the honeycombcore could go undetected, and providing guidance forinspecting the rudders. The Safety Board is recommending amore stringent compliance time than specified in the AOT andalso requesting that FAA make the inspections mandatory. More recent examinations have disclosed that hydraulicfluid can exist along the edges of the rudder’s innersurface along with an accompanying area of substantialdisbonding and that the inspection specified in the AOTscannot detect the presence of the hydraulic fluid or thedisbonding along the edges. Therefore, the Safety Board is recommending that theFAA require that all operators of Airbus A-300 seriesairplanes immediately (possibly before further flight)comply with four Airbus All Operators Telexes dated March 2,2006. Any disbonding to the rudder skins that occurs in thepresence of hydraulic fluid contamination should be repairedor the rudder should be replaced as soon as possible, wellbefore the 2, 500 flights specified in the AOTs. (A-06-27) This is an urgent recommendation. The NTSB further recommended that the FAA establish arepetitive inspection interval for Airbus premodification8827 rudders until a terminating action is developed. Theinterval should be well below 2,500 flights. (A-06-28) It is estimated that these recommendations concernabout 400 aircraft in Airbus’s worldwide fleet. A copy of the recommendation letter may be found atthe following link on the Board’s website:http://www.ntsb.gov/recs/letters/2006/A06_27_28.pdf- 30 -NTSB

Media Contact: Keith Holloway, (202) [email protected]