AD/BEECH 1900/12 - Pneumatic Air System Plumbing (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

Beechcraft 1900 Series Aeroplanes

AD/BEECH 1900/12 Pneumatic Air System Plumbing 11/95

Applicability: This Directive is applicable to the following aircraft:

Model Serial Numbers

1900 UA-2 and UA-3

1900C UB-1 through UB-74 and UC-1 through UC-174

1900C (C12J) UD-1 through UD-6

1900D UE-2 through UE-115

Requirement: Modify the plumbing of the pneumatic air system in accordance with the instructions provided with the following Beechcraft kits and as specified in the applicable Beechcraft Mandatory Service Bulletin:

Models Kit Number Service Bulletin 1900 and 1900C 118-9003-1 or 118-9003-3 2539 1900D 129-9010-1 or 118-9010-3 2591

Note: FAA AD 95-14-02 Amdt 39-9294 refers and supersedes FAA AD 91-24-15 Amdt 39-8173.

Compliance: Within 1,000 hours time in service after 12 October 1995 or by 31 December 1997, whichever occurs first.

Background: This Directive supersedes and cancels AD/BEECH 1900/6 which mandated certain modification of the instrument/pneumatic air system. Following eight additional reports of moisture freezing in the pneumatic air system plumbing of Model 1900 and 1900C aircraft, fitted with the same modification as that required by AD/BEECH 1900/6, the FAA determined that further modifications were required. Recent testing of the Model 1900D by the FAA also indicates that the design of the pneumatic air system on these aircraft is also conducive to moisture freezing. Actions specified by this Directive are designed to prevent ice formation in the pneumatic air system, which, if not detected, could result in the vacuum for the deice boot operation being unavailable which could result in the subsequent loss of the aircraft.