Airworthiness Directive · Amendment 39-15734 · Hawker Beechcraft Corporation Model 390 Airplanes
Hawker Beechcraft Corporation Model 390 Airplanes
This AD applies to Model 390 airplanes, serial numbers RB-4 through RB-224, that are certificated in any category.
We are adopting a new airworthiness directive (AD) for certain Hawker Beechcraft Corporation (HBC) Model 390 airplanes. This AD requires you to remove the current preformed packing, elbow fitting, and jam nut from the left and right hydraulic pump pressure output port and replace with new parts. This AD also requires you to install a hydraulic pump case drain check valve. This AD results from nine occurrences of hydraulic fluid leaking from the engine hydraulic pump output fitting as a result of an improperly installed elbow connecting the output port to the pulse dampener hose. We are issuing this AD to prevent hydraulic fluid leaks from the left and right hydraulic fluid pump and to prevent the flow of hydraulic fluid into the engine compartment. The loss of hydraulic fluid can result in loss of airplane hydraulic system pressure and the consequent loss of hydraulic system functions including gear extension/retraction, spoiler functions, and anti-skid braking system actuation. The inability of the hydraulic installation to isolate flow of hydraulic fluid could result in a hazardous amount of flammable fluid in the corresponding engine compartment. These conditions, if not corrected, could result in loss of system functions and/or fire in the engine compartment.
To address this problem, you must do the following, unless already done:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Remove current preformed packing (part number (P/N) MS28778-6), elbow fitting (P/N MS21908J6), and jam nut (P/N AN924-6J) from the left and right hydraulic pump pressure output port and install new preformed packing (P/N MS28778-6), union (P/N MS21902J6), and swivel fitting (P/N NAS1762J0606) in the left and right hydraulic pressure pump output port | Within the next 200 hours time-in-service (TIS) after December 22, 2008 (the effective date of this AD) or within the next 6 months after December 22, 2008 (the effective date of this AD), whichever occurs first | Follow Hawker Beechcraft Mandatory Service Bulletin SB 29-3869, dated January 2008. |
| (2) Install hydraulic pump case drain check valve Kit No. 390-5803-0001 | Within the next 200 hours TIS after December 22, 2008 (the effective date of this AD) or within the next 6 months after December 22, 2008 (the effective date of this AD), whichever occurs first | Hawker Beechcraft Mandatory Service Bulletin SB 29-3851, dated January 2008. |
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
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