Airworthiness Directive · Amendment 39-13830 · Raytheon (Beech) Model MU-300-10, 400, 400A, and 400T Series Airplanes; and Raytheon (Mitsubishi) Model Beech MU-300 Airplanes
Raytheon (Beech) Model MU-300-10, 400, 400A, and 400T Series Airplanes; and Raytheon (Mitsubishi) Model Beech MU-300 Airplanes
This AD applies to Raytheon (Beech) Model MU-300-10, 400, 400A, and 400T series airplanes; and Raytheon (Mitsubishi) Model Beech MU-300 airplanes; certificated in any category; as listed in Raytheon Service Bulletin SB 53-3486, dated June, 2003.
The FAA is adopting a new airworthiness directive (AD) for certain Raytheon (Beech) Model MU-300-10, 400, 400A, and 400T series airplanes; and certain Raytheon (Mitsubishi) Model Beech MU-300 airplanes. This AD requires a one-time inspection of certain panels in the spoiler mixer bay for the presence of drain holes, and the addition of at least one new drain hole; and a one-time inspection for discrepancies of the sealant on the relief cutout on the aft pressure bulkhead, and on certain baffles; and corrective actions if necessary. This AD is prompted by a report of fuel leaking from components in the spoiler mixer bay of several Raytheon (Beech) Model 400A series airplanes. We are issuing this AD to prevent the accumulation of fuel and/or fuel vapor in the spoiler mixer bay and/or the aft fuselage compartment, which could result in a fire in the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 400 flight hours or 12 months after the effective date of this AD, whichever occurs first, do the actions in paragraphs (f)(1) and (f)(2) of this AD. Do all actions in accordance with the Accomplishment Instructions of Raytheon Service Bulletin SB 53-3486, dated June 2003.
(1) Do a one-time general visual inspection of the spoiler mixer bay panels to determine the presence of drain holes. Before further flight after doing this inspection, drill at least one new drain hole, and any additional drain holes needed to make a total of five, at the places in each mixer bay panel specified in the service bulletin.
(2) Do a one-time general visual inspection for discrepancies of the sealant on the relief cutout on the aft pressure bulkhead, and of the small triangular-shaped baffles at left butt line (BL) 19.13 and right BL 10.43. Before further flight after doing this inspection, do any applicable corrective actions.
Note 1: For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
As of the effective date of this AD, no person may install on any airplane a spoiler mixer bay panel that has a part number listed in paragraph 3.B., “Spares,” of the Accomplishment Instructions of Raytheon Service Bulletin SB 53-3486, dated June 2003, unless the panel has been inspected and modified in accordance with paragraph (f)(1) of this AD.
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.
