COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Fairchild (Swearingen) SA226 and SA227 Series Aeroplanes
AD/SWSA226/57
Amdt 1
Battery Bus Relay 10/90
Applicability: All model SA226-T S/N T201 through T275 and T277 through T291; SA226-T(B) S/No T(B) 276, and T(B) 292 throught T(B) 417; SA226-AT S/No AT 001 thorught AT 074; SA226-TC S/No TC 201 through TC 419; SA227TT S/No TT 421 through TT 541; SA227-AT S/No AT 423 through AT 695; SA227-AC S/No AC 406, AC
415, AC 416, AC 420 through AC 705, and AC 707 through AC 733.
Requirement: Modify the battery bus relay electrical system as follows:
- Remove the access cover from the ‘J-box’, EP 11;
2. Remove the diode from terminals X1 and X2 of the battery bus relay K40;
3. Reinstall access cover; and
4. Using the battery switches, varify that battery voltage is present on the LH essential, RH essential and non essential busses.
Note: Fairchild SB’s SA226-24-032, SA227-24-013 and FAA AD 90-03-19 R1 also
refer.
Compliance: Prior to exceeding 100 hours time in service from 17 May 1990.
Background: Fairchild and the FAA have determined that a short circuited battery relay diode will cause de-energization of the battery relay and prevent any subsequent re-energization of the battery relay. This in combination with the loss or interruption of electrical power could result in an un-recoverable loss of electrical power to the aircraft. Tests by Fairchild indicate that removal of the battery relay diode as required by this AD did not impose any high voltage spike problems on the DC system.
Amendment 1 to this AD is issued to correct the applicable S/No range only. - No additional work is required.
Overview
The Civil Aviation Regulations 1998, specifically Part 39, incorporates Airworthiness Directives (AD) under the oversight of the Civil Aviation Safety Authority (CASA). One such AD is AD/SWSA226/57 Amendment 1, which pertains to the Fairchild (Swearingen) SA226 and SA227 Series Aeroplanes. Enacted to address safety concerns related to the electrical systems of these aircraft models, this AD was introduced to mitigate the risk of de-energization of the battery relay due to a short-circuited battery relay diode, which could lead to an unrecoverable loss of electrical power. The directive mandates modifications to the battery bus relay electrical system and requires compliance before the aircraft exceeds 100 hours of time in service from 17 May 1990. The policy objective is to enhance aviation safety by preventing potential electrical failures that could compromise aircraft operations.
Scope and Application
The Civil Aviation Safety Authority (CASA) Regulations 1998, specifically Part 39 - 105, which is the Schedule of Airworthiness Directives for Fairchild (Swearingen) SA226 and SA227 series aeroplanes, mandates particular modifications to the battery bus relay system. This directive applies to certain serial numbers of the SA226-T, SA226-T(B), SA226-AT, SA226-TC, SA227-TT, SA227-AT, and SA227-AC models. The requirement is for the removal of a specific diode from the battery bus relay K40, followed by a verification of battery voltage on the relevant busses. This modification must be completed prior to the aircraft exceeding 100 hours of time in service from the directive's effective date of 17 May 1990. The regulation is geographically applicable within Australia and adheres to the jurisdictional authority of the Civil Aviation Safety Authority, encompassing all relevant aircraft operating within the Commonwealth of Australia. There are no stated exclusions or exemptions in the directive itself, and any further details or specifications are left to the interpretation of the subordinate instruments issued by CASA.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, include the Civil Aviation Safety Authority Schedule of Airworthiness Directives. One such directive pertains to Fairchild (Swearingen) SA226 and SA227 Series Aeroplanes, identified as AD/SWSA226/57 Amendment 1. This directive focuses on the modification of the battery bus relay electrical system (section 1). The directive applies to specific serial numbers of the SA226-T, SA226-T(B), SA226-AT, SA226-TC, SA227-TT, SA227-AT, and SA227-AC models (section 2).
Under this directive, operators must modify the battery bus relay electrical system by removing the access cover from the 'J-box', EP 11, removing the diode from terminals X1 and X2 of the battery bus relay K40, reinstalling the access cover, and verifying the battery voltage on the left-hand essential, right-hand essential, and non-essential busses using the battery switches (section 3). Compliance with these requirements must be achieved before the aircraft exceeds 100 hours of time in service from 17 May 1990 (section 4).
The obligations imposed by this directive are clear: operators must ensure that the specified modifications to the battery bus relay system are performed before the aircraft accumulates 100 hours of operational time. This involves the removal and reinstallation of specific components and verification of electrical integrity through battery voltage checks. The directive references relevant service bulletins and FAA airworthiness directives, indicating that this modification is integral to maintaining the aircraft's airworthiness and preventing potential electrical failures.
Failure to comply with the provisions of this airworthiness directive could result in significant safety risks. The Civil Aviation Regulations 1998 do not explicitly detail penalties for non-compliance within this directive, but non-compliance with airworthiness directives generally can lead to enforcement actions by the Civil Aviation Safety Authority. Such actions may include fines, grounding of the aircraft, or other regulatory penalties. Ensuring adherence to the directive is thus critical to maintaining the operational safety and legality of the aircraft.