AD/B747/283 - Fuel Tank Limitations

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Legislation au F2006B03178 In force Legislative Instrument

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AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

 

Boeing 747 Series Aeroplanes

 

AD/B747/283 Fuel Tank Limitations 1/2003 TX

 

Applicability: All Model 747 series aeroplanes.

 

Requirement:  Revise the Limitations Section of the Aircraft Flight Manual (AFM) to include the following (this may be accomplished by inserting a copy of this Directive into the AFM):

 

Model 747-100, -200B, -200F, -200C, -100B, -300, -100B SUD, 747SR and 747SP

 

CERTIFICATE LIMITATIONS

 

Fueling and use of the centre auxiliary fuel tank and auxiliary fuel tanks 1 and 4 (if installed) is prohibited.

The centre wing tank (CWT) must contain a minimum of 17,000 pounds (7,700 kilograms) of fuel prior to engine start, if the CWT override/jettison pumps are to be selected ON during flight.

The CWT fuel quantity indication system must be operative to dispatch with CWT mission fuel.

Both CWT override/jettison pump switches must be selected OFF at or before the CWT fuel quantity reaches 7,000 pounds (3,200 kilograms), if the CWT fuel quantity is less than 50,000 pounds (22,700 kilograms) prior to engine start. The CWT override pumps may be selected ON during stabilized cruise conditio ns. Both CWT override/jettison pump switches must be selected OFF at or before the CWT fuel quantity reaches 3,000 pounds (1,400 kilograms).

 

Both CWT override/jettison pump switches must be selected OFF at or before the CWT fuel quantity reaches 3,000 pounds (1,400 kilograms), if the CWT fuel quantity is greater than or equal to 50,000 pounds (22,700 kilograms) prior to engine start.

 

Both CWT override/jettison pumps must be selected OFF when either CWT override/jettison fuel pump low pressure light illuminates.

 

Boeing 747 Series Aeroplanes

 

AD/B747/283 (Continued)

 

Warning

 

Do not reset a tripped fuel pump circuit breaker.

 

Warning

Do not cycle the CWT pump switches from ON to OFF to ON with any continuous low pressure indication present.

Note

 

The CWT may be emptied normally in an emergency fuel jettison.

Note

In a low fuel situation, both CWT override/jettison pumps may be selected ON and all CWT fuel may be used.

If a centre wing tank pump fails with fuel in the centre tank, shut off the affected fuel pump.

If the main tanks are not full, the zero fuel gross weight of the aeroplane plus the weight of CWT tank fuel may exceed the maximum zero fuel gross weight by up to 7,000 pounds (3,200 kilograms) for takeoff, climb, cruise, descent, and landing, provided that the effects of balance (CG) have been considered.

 

When defueling centre or main wing tanks, the Fuel Pump Low Pressure indication lights must be monitored and the fuel pumps positioned to OFF at the first indication of fuel pump low pressure. Defueling with passengers on board is prohibited.

Model 747-400, -400D, and -400F CERTIFICATE LIMITATIONS

Fueling and use of the horizontal stabilizer tank (if installed) is prohibited.

 

The centre wing tank (CWT) must contain a minimum of 17,000 pounds (7,700 kilograms) prior to engine start, if the CWT override/jettison pumps are to be selected ON during flight.

 

The CWT fuel quantity indication system must be operative to dispatch with CWT mission fuel.

 

Both CWT override/jettison pump switches must be selected OFF at or before CWT fuel quantity reaches 7,000 pounds (3,200 kilograms), if CWT fuel quantity is less than 50,000 pounds (22,700 kilograms) prior to engine start.

The CWT override pumps may be selected ON during stabilized cruise conditions. Both CWT override/jettison pump switches must be selected OFF at or before the CWT fuel quantity reaches 3,000 pounds (1,400 kilograms).

Note

 

With CWT override/jettison pumps selected OFF and CWT fuel quantity greater than 6,000 pounds (2,800 kilograms), the FUEL OVRD CTR L & R EICAS messages will be displayed. Do not accomplish the associated non- normal procedure.

 

Both CWT override/jettison pump switches must be selected OFF at or before CWT fuel quantity reaches 3,000 pounds (1,400 kilograms), if CWT fuel quantity is greater than or equal to 50,000 pounds (22,700 kilograms) prior to engine start.

Both CWT override/jettison pumps must be selected OFF when either CWT override/jettison fuel pump low pressure light illuminates.

Warning

Do not reset a tripped fuel pump circuit breaker.

 

Warning

 

Do not cycle CWT override/jettison pump switches from ON to OFF to ON with any continuous low pressure indication present.

Note

The centre wing tank may be emptied normally during an emergency fuel jettison.

 

Note

 

In a low fuel situation, both CWT override/jettison pumps may be selected ON and all CWT fuel may be used.

 

If a centre wing tank pump fails with fuel in the centre tank, accomplish the FUEL OVRD CTR L, R non- normal procedure.

 

If the main tanks are not full, the zero fuel gross weight of the aeroplane plus the weight of CWT tank fuel may exceed the maximum zero fuel gross weight by up to 7,000 pounds (3,200 kilograms) for takeoff, climb, cruise, descent, and landing, provided that the effects of balance (CG) have been considered.

 

When defueling any fuel tanks, the Fuel Pump Low Pressure indication lights must be monitored and the fuel pumps positioned to OFF at the first indication of fuel pump low pressure. Defueling with passengers on board is prohibited.

The limitations contained in this Directive supersede any conflicting basic Aircraft Flight Manual limitations.

 

Accomplishment of Requirement 2 of AD/B747/280 is acceptable for compliance with the requirements this Directive. This Directive does not require that those actions be repeated unless the terminating actions specified in Requirements 4, 6 and 7 of AD/B747/280 have been accomplished.

Accomplishment of the terminating actions specified in Requirement 4, 6 and 7 of AD/B747/280, does not allow removal of the AFM revisions required by this Directive.

 

Note: FAA Emergency AD 2002-24-51 and AD2002-24-52 refer.

 

Compliance: Before 29 November 2002.

 

This Airworthiness Directive becomes effective on 26 November 2002.

 

Background: The United States Federal Aviation Administration has received reports indicating that two fuel tank pumps from different Model 747 series aeroplanes showed evidence of extreme localized overheating of parts in the priming and vapour pump section of the fuel pump. The priming and vapour pump section of the pump is open to the fuel tank via the pump inlet line and the vapour vent of the pump. The cause of this overheating is believed to be friction between the pump parts; however, the specific cause of the friction is unknown at this time.

 

Overheating of the parts in the priming and vapour pump section of the fuel pump provides an ignition source in the fuel tank during dry running of the pump, which could result in fire/explosion of the fuel tank.

 

This Directive requires revision of the AFM to require the flight crew to maintain certain minimum fuel levels in the centre fuel tanks, together with a prohibition of the use of the horizontal stabilizer fuel tank (for Model 747-400 series aeroplanes) and certain centre auxiliary fuel tanks (on Model 747 series aeroplanes). These procedures specify crew monitoring of fuel levels and shutoff of centre fuel tank pumps at specified levels that ensure the pump inlet remains covered during pump operation. Covering the pump inlet prevents fuel vapours from coming into contact with potentially overheated parts in the priming and vapour pump section of the fuel pump, together with the likelihood of preventing the overheating condition itself.

This action is considered interim and further rule making is anticipated.


 

James Coyne

Delegate of the Civil Aviation Safety Authority 25 November 2002

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


The above AD is notified in the Commonwealth of Australia Gazette on 26 November 2002.

Overview

The Civil Aviation Safety Authority (CASA) issued Airworthiness Directive AD/B747/283 on 26 November 2002, aimed at addressing the safety issue of potential overheating in the fuel tank pumps of Boeing 747 series aeroplanes. This directive was enacted under subregulation 39.1(1) of the Civil Aviation Regulations 1998, responding to reports from the United States Federal Aviation Administration of extreme localised overheating in the priming and vapour pump sections of fuel tank pumps. The overheating, believed to be caused by friction between the pump parts, posed a risk of ignition within the fuel tanks, leading to potential fire or explosion. The directive's primary policy objective is to mitigate this risk by imposing specific limitations on the use of certain fuel tanks and mandating minimum fuel levels in the centre wing tanks to prevent dry running of the fuel pumps. This Airworthiness Directive applies to all models of the Boeing 747 series aeroplanes and requires the revision of the Aircraft Flight Manual to include the specified fuel tank limitations. It prohibits the use of certain auxiliary fuel tanks and the horizontal stabilizer tank, depending on the model, and mandates that the flight crew maintain a minimum fuel level in the centre wing tank before engine start. Additionally, it specifies conditions under which the fuel tank pumps must be shut off to avoid overheating and ignition risks. Compliance with this directive is required before 29 November 2002, ensuring that all affected aircraft adhere to the new safety measures to prevent potential fire hazards.

Scope and Application

The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998 pertains specifically to all Model 747 series aeroplanes, including various sub-models such as the 747-100, -200B, -200F, -200C, -100B, -300, -100B SUD, 747SR, and 747SP. The directive mandates revisions to the Aircraft Flight Manual (AFM) to address unsafe conditions related to the overheating of fuel pump parts, which could potentially lead to fire or explosion within the fuel tanks. The AD is applicable to all operators and flight crews of the specified Boeing 747 series aeroplanes, necessitating compliance with the outlined fuel management protocols and limitations. These include prohibitions on the use of certain fuel tanks and the implementation of minimum fuel level requirements to prevent dry running of the fuel pumps, thus mitigating the risk of overheating. The directive is effective from 26 November 2002, and compliance must be achieved before 29 November 2002. This AD extends its jurisdictional reach across the Commonwealth, enforcing strict operational standards to ensure air safety.

Key Provisions

The Airworthiness Directive (AD) AD/B747/283 (section 1) mandates specific actions for all Boeing 747 series aeroplanes to address the safety concerns related to overheating of fuel pump components. The requirement (section 2) is to revise the Limitations Section of the Aircraft Flight Manual (AFM) to include specific fuel management procedures. These include prohibiting the use of certain auxiliary and centre fuel tanks, setting minimum fuel levels in the centre wing tank before engine start, and specifying conditions for switching off the centre wing tank override/jettison pumps. Additionally, operators are advised against certain actions such as resetting a tripped fuel pump circuit breaker or cycling the pump switches under low-pressure conditions. The AD imposes obligations on operators of Boeing 747 series aeroplanes to ensure compliance with the revised AFM limitations by the specified compliance date (section 3). Operators must integrate the AD's requirements into their operational procedures, including training their flight crews on the new limitations and ensuring that all flight manuals are updated accordingly. The AD also references other related ADs (section 4) and specifies that compliance must be achieved before 29 November 2002. Failure to comply with this AD can result in serious safety risks, including the potential for fuel tank fires or explosions due to overheating of fuel pump components. Under Australian law, non-compliance with an AD can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). Potential consequences include fines, operational restrictions, or more severe penalties if the non-compliance results in an accident or incident. The specific penalties are not detailed in the AD but typically align with the severity of the non-compliance and its impact on aviation safety.

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Sourced from the Federal Register of Legislation at 26 August 2026. For the latest information on Australian Government law please go to https://www.legislation.gov.au.