Flap actuator lubrication – Challenger 300 series
Effectivity: Challenger 300/350/3500 aircraft
ATA: 27 - Flap
By: Patrick Bernèche – Technical Services Every 600 hours or 12 months (whichever occurs first), lubrication of the inboard and outboard flap actuators is required (Chapter 5 Task 27-52-13-201).
Some operators reported that during the lubrication, they could not grease the actuators (see Reference 1) because some grease fittings were found with the ball valve stuck in the open position and did not take any grease. Consequently, many flap actuator assemblies were removed and returned to the vendor for repair.
Reference 1
Vendor evaluation showed that in many cases, the spring installed inside the grease fitting (see Reference 2) was forced and pushed through the grease exit hole due to excessive pressure on the ball valve. Stuck in the open position, the ball valve clogs the grease exit hole and the grease fitting becomes unusable.
Reference 2 (Grease fitting p/n NAS 516-1A)
In most cases, the damage was caused by the use of an unapproved tool. Needle type nozzles or shop air pressurized grease guns can produce excessive pressure inside the grease fitting and cause damage. To prevent damaging the grease fittings during the lubrication, the ground support equipment (GSE) 27C-52-01 (p/n GWKTBB-300) was purposely designed to perform lubrication of the flap actuators. This is a grease gun assembly equipped with a specially designed greasing nozzle meeting MS24203-1 specifications, a 24-inch flexible hose and dedicated low-pressure one-hand operated grease gun that allows the use of a standard 14 oz cartridge.
The complete assembly (see Reference 3) meets flap actuator manufacturer requirements and will minimize potential damage. This GSE is available from Bombardier as a turnkey solution in lieu of the “commercially available” component specifications listed under the AMM task 27-52-00-640-801 (Lubrication of the Inboard and Outboard Flap Actuator).
Reference 3
To reduce the cost associated with the replacement of an actuator, the lubrication task has been revised with instructions that allow the replacement of the flap actuator grease fitting. Replacement fitting P/N NAS 516-1A is available from Bombardier spare parts.
Furthermore, to ease the maintenance if the recommended tools are not readily available, RIL BD-0034 allows the use of standard shop tools to extract and install a grease fitting NAS516-1A. RIL BD-0034 is available on the Customer Portal: https://my.businessaircraft.bombardier.com > Technical Library > Challenger > Engineering Documents > RIL BD-0034.
If you have any questions concerning the flap actuator grease fitting replacement procedure, please contact your local Field Service Representative or the Customer Response Centre (CRC).