The FAA released AD 2019-08-08 for CL601/CL604 (and subsequent variants) effective on June 27, 2019, prompted by reports of on-ground hydraulic accumulator screw/end cap failure that resulted in loss of the associated hydraulic system and high-energy impact damage down range of adjacent systems and structure.

The terminating action of this AD is accomplished by c/w SB 601-0637 for CL601 aircraft (s/n 3001 to 3066, 5001 to 5194), or by c/w SB 604-29-013 R2 for CL604 aircraft (s/n 5301 to 5665).

These Service Bulletins remove the existing hydraulic system #3 accumulator and its pressure gauge/valve from the main landing gear bay and relocate them to the LH side, rear wing-to-fuselage fairing area of CL604’s or to the LH side of the aft belly fairing on CL601’s.

Compliance is mandatory within 60 months or 2,400 flight cycles (whichever occurs first) from the AD effective date of June 2019.

These Service Bulletins are covered by a dedicated schedule and parts kits are limited with extremely long lead-times in the 8–12-month range once the order is placed. Therefore, it is essential to plan well in advance to get the kits on order before time runs out for the operator.

If the aircraft does not have the LH hydraulic door previously installed, this must be accomplished at the same time as the accumulator relocation but will entail additional parts and labor. Smart Parts Plus does not pay for these kits to accomplish this modification.

West Star Aviation recommends performing these SB’s during the aircraft’s next 96-Month inspection while the aft lavatory or equipment/furnishings are removed.