A310 Rudder Attachment Failure and Separation

The A310 rudder separation is possibly related to trapped moisture freezing at altitude (i.e. expanding and leading to failure of the top rudder hinge-bracket attachment point - which seems to be missing in the photos - but is obvious from the photo below of an intact attached rudder. i.e. that top hinge and the fin-mounted bracket departed with the rudder).

The theory there is that moisture is more likely to gather/be trapped at the top of the rudder internally. Once the rudder hinge-bracket failed at that topmost point, the upper part of the rudder would be somewhat similar to a flag flying in a breeze. The resultant flail-induced flutter would probably get out of sync with the induced upper fin-flutter and the rudder's composite structure would rip away, from the top down. Think of holding a sheet of paper at the bottom and 3/4ths of the way up out of a car window at speed. The unrestrained 1/4 would tear away if you were going fast enough.

However there are also a number of applicable AD's (and who knows how many Service Bulletins or Service Information Letters). See some of those reproduced in part (with links) below the graphics.

 
See the solid shadow below the fin trailing edge cross-strut by comparison with the absence of any such shadow on the cross-struts below (appears to indicate a closed compartment (i.e. a possible moisture-trap). Moisture traps can also form when drain-holes become clogged by liberal grease insertions into a hinge via an access port.

Just above that arrow-point is where the top rudder hinge-bracket should be

 

 
Note missing topmost rudder hinge-bracket (went with rudder).

 Normally the reason for such a failure would be a loss of bracket attachment-point strength due to disbonding and delamination brought about by moisture ingress/freeze and refreeze cycles)

 

 
Note position of uppermost rudder hinge attachment point access port.

Not sure that the position of the trailing edge static wicks would be relevant except inasmuch as being the shortest path to the static wicks exit-point for a lightning strike elsewhere on the airplane would've been via the uppermost rudder hinge-bracket. That may have scorched and weakened (delaminated) the composite fin's side of the rudder hinge-bracket attachment.

 

 
Part of a rudder hinge-bracket can be seen here just behind the top of the rudder remnant.
 
Expanded View
 
A different perspective
 
Some A310 tail hangar rash
 
A310 AD's (affecting rudders) - Highlit for Significance to Air Transat Rudder Loss
AD 2005-04-11 Airworthiness Directives; Airbus Model A300 B2 and B4 Series Airplanes; A300 B4-600, B4-600R and F4-600R Series Airplanes, and Model C4-605R Variant F Airplanes (Collectively Called A300-600); and A310 Series Airplanes
Unsafe Condition

(d) This AD was prompted by a decision by the FAA and a civil airworthiness authority to require modification or replacement of all affected parking brake operated valves (PBOV). We are issuing this AD to prevent loss of the yellow hydraulic system, which provides all the hydraulics for certain spoilers; elements of the hydraulics for flaps, stabilizer, pitch and yaw feel systems, pitch and yaw autopilot, and yaw damper; and elevator, rudder, and aileron.

effective date: 05 Apr 05

AD 2005-03-14 Airbus Model A300 B2 and B4 Series Airplanes (but not A310?)

amendment supersedes an existing airworthiness directive (AD) that applies to all Airbus Model A300 B2 and B4 series airplanes. The existing AD currently requires determining the part and amendment number of the variable lever arm (VLA) of the rudder control system to verify the parts were installed using the correct standard, and corrective actions if necessary. For certain VLAs, this new AD requires repetitive inspections of the VLA and corrective action if necessary. This new AD also provides a terminating action for the repetitive inspections. Furthermore, this new AD reduces the applicability of affected airplanes. The actions specified by this AD are intended to prevent failure of both spring boxes of certain VLAs due to corrosion damage, which could result in loss of rudder control and consequent reduced controllability of the airplane.

....before further flight, do a detailed inspection of the VLA tie rod for damage (bent or ruptured rod)

....If any damage is found to the VLA or the rudder control system during any inspection .......

effective date: 21 Mar 05

AD 98-13-33 SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to all Airbus Model A300, A300-600, and A310 series airplanes, that requires repetitive tests to detect desynchronization of the rudder servo actuators, and adjustment or replacement of the spring rods of the rudder servo actuators, if necessary. For certain airplanes, this AD also requires repetitive inspections to detect cracking of the rudder attachments, and repair, if necessary; or modification of the rudder attachments. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to detect and correct desynchronization of the rudder servo actuators, which could result in reduced structural integrity of the rudder attachments and reduced controllability of the airplane

(1) Conduct a visual inspection, high frequency eddy current inspection, or ultrasonic inspection, as applicable, to detect cracking of the rudder attachments; and repeat the inspection thereafter, as applicable, at the intervals specified in the applicable service bulletin. Or

(2) Modify the rudder attachments to cold expand the rivet holes.

DATES: Effective July 30, 1998.

The subject of this AD is addressed in French airworthiness directive 96-242-208(B) R2, dated November 19, 1997.

AD 99-16-14 SUMMARY: This amendment adopts a new airworthiness directive (AD) that is applicable to all Airbus Model A300, A310, and A300-600 series airplanes. This action requires a one-time inspection of the autopilot systems for proper engagement to determine if the main electro valve electrical connectors of the yaw, roll, and pitch autopilot actuators are correctly installed; and corrective actions, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to prevent erratic movements of the ailerons, elevator, and/or rudder that are commanded by discrepant autopilot actuators, which could result in reduced controllability of the airplane.
One operator of an Airbus Model A300-600 reported high rudder forces and uncommanded rudder inputs during final approach. The uncommanded rudder inputs caused deflections of the rudder control surface resulting in yawing of the airplane. Investigation of the incident is ongoing, but preliminary results indicate that failure of both the main valve and the clutch valve of the autopilot yaw actuator can lead to the actuator generating uncommanded rudder deflections.

DATES: Effective August 24, 1999.

 
This is another "post AA587" AD that applies to A310's as well  (in addition to the compendium of relevant AD's above)

AD/AB3/183 Vertical Stabiliser and Rudder Attachment 1/2002

DM

Applicability: All Model A300-600 and A310 aircraft, equipped with post modification 4886

(composite) vertical stabilisers.

Requirement: Perform one-time detailed visual inspections in accordance with DGAC Telegraphic

AD T2001-560(B).

Compliance: Within 15 days after 28 November 2001, unless already accomplished.

This Airworthiness Directive becomes effective on 28 November 2001.