Disbonded Or Missing Cable Guards Cited In The Bulletin

The FAA has issued an SAIB (Special Airworthiness Information Bulletin) concerning the degradation of normal aileron control of Hawker 4000 airplanes due to disbonded or missing cable guards.

The FAA received notification of field reports of disbonded or missing cable guards for the wing aileron cables. These guards are normally attached to the midboard and outboard spoiler actuator fittings. Two airplanes had higher-than-normal aileron forces during flight. The autopilot faulted off on one of these airplanes, followed by an amber “AP Roll Mistrim” CAS message, and a temporary restriction of aileron control. Reportedly, the pilot relaxed pressure on the ailerons and was able to operate them, although forces remained high. The flightcrew determined that operating the roll control disconnect mechanism to separate left and right aileron control was not necessary.

The cable guards are installed by adhesive bonding, which is disbonding, and the cause has not been determined. However, it has been determined that these cable guards are not necessary for proper functioning of the aileron control system and safe flight of the airplane. Removal of these cable guards will prevent the potential of loose or disbonded cable guards, which could result in degradation of aileron control. Hawker Beechcraft Corporation issued Mandatory Service Bulletin SB 27-4116, dated December 2012, to provide operators with guidelines for removing the existing cable guards for the wing aileron cables.

The FAA recommends that all owners and operators of the subject airplanes incorporate the modifications outlined in Hawker Beechcraft Mandatory Service Bulletin SB 27-4116, dated December 2012.

The agency requests that owners and operators report the date of removal of the cable guards, or if the cable guards were not removed, to Paul DeVore.

(Hawker 4000 pictured in file photo)

FMI: SAIB