COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series
AD/TPE 331/52 PT2 Sensor Icing 11/97
Applicability: TPE331-3, -5, -6, -10, -11, -12 series engines not incorporating a Pt2 sensor modified in accordance with AlliedSignal Service Bulletins (SB) TPE331-73-0235 or TPE331- 73-0236 as applicable by engine model.
Requirement: 1. All applicable aircraft:
To prevent the loss of control of engine power when operating in icing conditions, modify the Pt2 sensor in accordance with the requirements of AlliedSignal SB TPE331-73-0235 or TPE331-73-0236 as applicable by engine model number.
2. Aircraft equipped with engine inlet ice protection:
To address the possible loss of control of engine power when operating in icing conditions; pending the issue of an amendment to the Approved Flight Manual, a copy of this directive shall be placed in the Approved Flight Manual as the first page of the emergency or abnormal procedures section to reflect:
“NON RESPONSIVE POWER LEVER:
If a lack of response to power lever is observed, turn on the ignition and anti-ice for both engines. After the condition has cleared and normal operations are observed, which occurs in approximately three minutes, anti-ice and ignition can be turned off.”
Note 1: Compliance with the requirements of SB TPE331-73-0235 or TPE331-73- 0236 constitutes a terminating action for the requirements of this directive.
Note 2: FAA Airworthiness Directive 97-15-10 refers.
Compliance: 1. As detailed in the requirement documents.
2. Within 30 days from the effective date of this directive.
This airworthiness directive becomes effective on 9 October 1997.
Background: This directive has been issued to address reports of ice blockage of the Pt2 probe.
Icing of the Pt2 probe can result in erroneous signals to the fuel control unit causing little or no response to power lever movement. This directive requires the modification of the Pt2 sensor to provide Pt2 sensing in the event of the probe icing and to increase anti-ice flow to the Pt2 sensor to optimise the de-icing time.
Overview
The Civil Aviation Regulations 1998, established under the authority of the Civil Aviation Act 1988, were enacted to ensure the safety and efficiency of civil aviation within Australia. This legislation was introduced to address the need for comprehensive regulations governing the operations of civil aircraft, aiming to ensure the highest standards of safety and efficiency in the aviation industry. One of the key provisions of the Civil Aviation Regulations 1998 is Part 39, which includes the schedule of airworthiness directives, such as AD/TPE 331/52 concerning the AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series. This directive was introduced to specifically address the problem of Pt2 sensor icing in certain TPE 331 series engines, which could lead to erroneous signals and loss of control of engine power in icing conditions. The policy objective is to enhance aircraft safety by preventing such failures and ensuring the reliability of engine performance under adverse weather conditions.
Scope and Application
The Civil Aviation Regulations 1998, particularly Part 39 - 106 and the Civil Aviation Safety Authority Schedule of Airworthiness Directives, apply to specific models of AlliedSignal (Garrett/AiResearch) Turbine Engines, namely the TPE 331 series. The directive AD/TPE 331/52 pertains to the TPE331-3, -5, -6, -10, -11, and -12 series engines that do not have a Pt2 sensor modified according to AlliedSignal Service Bulletins TPE331-73-0235 or TPE331-73-0236, depending on the engine model. This regulation is mandated at a Commonwealth level and applies to all aircraft utilising the specified engine models that meet the criteria mentioned. Compliance with the directive is required within 30 days from its effective date, which is 9 October 1997, and it was issued in response to reports of ice blockage in the Pt2 probe, which can lead to a lack of engine power response under icing conditions. The directive mandates modifications to the Pt2 sensor to prevent such issues and specifies procedures for aircraft equipped with engine inlet ice protection to manage non-responsive power levers during icing conditions.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 106, mandates modifications to the Pt2 sensor of AlliedSignal (Garrett/AiResearch) Turbine Engines of the TPE 331 series to prevent loss of control during icing conditions (AD/TPE 331/52). The directive applies to TPE331-3, -5, -6, -10, -11, -12 series engines that have not been modified in accordance with AlliedSignal Service Bulletins TPE331-73-0235 or TPE331-73-0236 as applicable by engine model. The primary requirement is that all applicable aircraft must modify the Pt2 sensor as specified in these bulletins to avoid the risk of losing engine power control when operating in icing conditions (Section 1). For aircraft equipped with engine inlet ice protection, the directive additionally mandates the inclusion of a specific procedure in the Approved Flight Manual until an amendment is issued, detailing the steps to follow if a lack of response to the power lever is observed (Section 2).
The regulations impose obligations on aircraft operators and maintenance personnel to ensure compliance with these requirements. Specifically, operators must ensure that the Pt2 sensor is modified according to the relevant AlliedSignal Service Bulletin, and for aircraft with engine inlet ice protection, the emergency procedure must be included in the Approved Flight Manual (Section 1). The directive also specifies that compliance must be achieved within 30 days from the effective date, which is 9 October 1997 (Section 1).
Failure to comply with the requirements of this airworthiness directive can result in serious consequences, including the potential loss of control of the engine during icing conditions, which could endanger the aircraft and its occupants. The regulations do not explicitly state penalties for non-compliance, but it is implied that failure to adhere to these safety directives could result in legal and safety ramifications. Operators and maintenance personnel are expected to ensure strict compliance to avoid any risk to flight safety.