On November 12th, an Airbus Model A300 B4-605R aircraft was involved in an accident shortly after takeoff from John F. Kennedy International Airport in New York causing a tragic loss of life to all its passengers and crew.
Since the accident, the aircraft’s vertical stabiliser and rudder have been found in Jamaica Bay in New York, having apparently come off the aircraft before the plane hit the ground.
The vertical stabiliser on Airbus Model A300-600 series aircraft with Airbus Modification 4886 is manufactured from carbon fibre reinforced epoxy. So is the vertical stabiliser on Airbus Model A310 series aircraft with the same modification.
And now, an investigation is underway to attempt to determine why those components separated in flight.
Failure of the vertical stabiliser-to-fuselage attachment fittings, transverse (side) load fittings, or rudder-to-vertical stabiliser attachment fittings, if not corrected, could have resulted in the loss of the vertical stabiliser and/or rudder and consequent loss of control of the aircraft.
Recently, opon issuing an airworthiness directive (AD) for the A300-600 aircraft, a statement from the US Federal Aviation Authority (FAA) indicated that, before such a structural failure occurs, it may be possible to detect indications of possible failure modes that could result in the separation of the vertical stabiliser from the aeroplane.
These indications would include edge delaminations, cracked paint, surface distortions, other surface damage, and failure of the transverse (side) load fittings. Similarly, indications of failure of the rudder assembly, which could lead to failure of the vertical stabiliser, may also be detectable with such an inspection.
Although neither the FAA nor the NTSB have reached conclusions with respect to these possible failures on the aircraft involved in the accident, they have stated that they consider it prudent to require an inspection of these structures to identify any such indication that may exist.
Since a potential unsafe condition may exist, the FAA has issued the AD to require a one-time detailed visual inspection to detect repairs and alterations to, and damage of the vertical stabiliser attachment fittings, including the main attachment lugs and the transverse (side) load fittings, and the rudder hinge fittings, hinge arms, and support fittings for all rudder hinges, and rudder actuator support fittings. It requires them to be repaired, if necessary.
The AD also requires that operators report results of inspection findings to the FAA.
This week, US National Transportation Safety Board (NTSB) structures investigators met with composite experts from Iowa State University, Sandia National Laboratories, the National Aeronautics and Space Administration and the FAA, to visually examine the tail structure at its temporary storage facility in New York.
The NTSB is planning to move the vertical stabiliser and rudder parts to NASA’s Langley Research Center in Hampton, Virginia. The facility was chosen to assist the Board in further examination of these components because of its expertise with composite materials and structures involving civil and military aircraft, and spacecraft.
The facility has capabilities that include materials synthesis and processing, analytical modelling, non-destructive evaluations, structural dynamics, aeroelasticity, structural durability and damage tolerance, and experimental methods.
Sources: FAA, NTSB