AD/EMB-120/49 Amdt 1 - Fuel Quantity Indication System

The central concepts in AD/EMB-120/49 Amdt 1 revolve around the Fuel Quantity Indication System (FQIS) and its verification. The FQIS is the system that provides the cockpit crew with information on the amount of fuel in each wing tank. It includes sensors (probes) in the tanks, a master indicator (likely on the overhead panel or primary display), and repeater indicators (such as on the centre pedestal or engine instrument displays). The directive requires the use of dripless measuring sticks - these are physical dipsticks inserted into the fuel tanks to obtain a precise measurement of the fuel level, without fuel leaking out during the process. The key technical parameter is the difference between the dipstick measurement (real fuel quantity) and the electronic indication (master and repeater). The threshold is 60 kg (132 lb). This number is not arbitrary; it likely represents an acceptable tolerance for the FQIS accuracy that does not pose a safety risk given the fuel consumption rates and flight planning margins. The directive specifies that the functional check must be performed using task reference 28-42-00 from one of five specified AMM publications: MM120/1459, MM120BAS/718, MM120CAL/921, MM120DLT/724, and MM120TEX/880, all with a revision date of 30 July 2004. Additionally, an alternative manual is referenced: OTFN 1VC97-2, which appears to be a Brazilian manual (titled Sistema Mecânico de Indicação de Quantidade de Combustível - Descrição e Operação) with pages dated 23 October 1986 and 8 October 1987. This suggests that the directive accommodates different operational contexts, such as aircraft operated under different national registrations. The concept of time in service (TIS) refers to the number of hours the aircraft has been operated since the last compliance or since the effective date. The 180 day interval provides a calendar-based alternative, recognising that not all aircraft accumulate hours at the same rate. The directive also introduces the concept of a grace period for corrective action: up to 10 days after the functional check if specific interim monitoring conditions are met. This balances safety with operational practicality, avoiding unnecessary grounding for minor discrepancies. The amendment itself corrects a typographical error in the compliance statements, indicating that precision in regulatory drafting is crucial for clear interpretation. The background statement from ANAC grounds the directive in a real-world failure mode: probe failure leading to false high fuel readings, which could lead to fuel starvation. This is a classic latent failure scenario where the system appears to work correctly but provides erroneous data, making the physical dipstick check the only reliable verification method.

This directive applies directly to any person or organisation responsible for the operation and maintenance of Embraer EMB-120 series aeroplanes registered in Australia. The applicability clause specifically lists models EMB-120, EMB-120RT, EMB-120ER, EMB-120FC, and EMB-120QC. This covers the standard commuter version, the extended range variant, the freighter combi, and the quick change passenger/freight model. The primary affected parties are aircraft operators - these could be scheduled regional airlines, charter operators, freight companies, or private owners who operate these aeroplanes. Maintenance organisations that perform heavy checks or line maintenance on EMB-120 aircraft are also affected, as they must incorporate this AD into their maintenance schedules and ensure their technicians are trained on the specific procedures. The directive also affects the Civil Aviation Safety Authority itself, which is responsible for issuing and enforcing the AD, and by extension, its delegates such as the signatory James Coyne. Additionally, the directive references the Brazilian ANAC AD 2009-07-04, indicating that manufacturers and foreign regulators are relevant parties. The original equipment manufacturer (Embraer) and the holder of the type certificate may also be indirectly affected, as they provide the maintenance manual data referenced in the directive. Aircraft lessors and financiers may require evidence of compliance with all applicable ADs as part of lease agreements or financing arrangements. For airlines that operate a fleet of EMB-120s, the 600 hour or 180 day repetitive inspection requirement creates a recurring operational burden. They must schedule access to the fuel tanks, which requires defuelling for access to the measuring sticks, adding to maintenance costs and aircraft downtime. The 10 day grace period for single-tank discrepancies allows some scheduling flexibility, but the conditions imposed (post-refuelling dip checks and operational flow indicators) impose additional workload on flight crews. The directive also affects parts suppliers who provide FQIS components, as the corrective action may involve replacing probes or adjusting the system. Finally, the directive has downstream effects on passengers and cargo customers, to the extent that compliance prevents fuel-related incidents and delays. However, the directive imposes costs directly on operators, which may be passed through to consumers in the form of higher airfares or freight charges, though this is not addressed in the directive itself. The background notes the safety rationale, but from an economic perspective, the directive imposes a specific compliance cost whose magnitude depends on the fleet size, utilisation rates, and existing maintenance practices.

AD/EMB-120/49 Amdt 1 imposes clear duties on the operator. The primary duty is to perform the functional check described in Requirement 1 within the specified timeframe: within 600 hours TIS or 180 days after the effective date of the original issue (27 August 2009), and then repetitively at intervals not exceeding 600 hours TIS or 180 days. The duty is to use the correct procedure from the AMM, with at least 400 kg of fuel in each tank, and to compare the dipstick measurement to both the master and repeater indicator readings. If the difference is 60 kg or less, the duty is fulfilled for that check. If the difference exceeds 60 kg on both tanks, the duty is to correct the FQIS indication before the next flight. If the difference exceeds 60 kg on only one tank, the operator has a conditional duty: they must either correct the FQIS indication within 10 days, or immediately if the three conditions for deferral are not met. The conditions for deferral themselves impose ongoing duties: after each refuelling, the operator must determine the real fuel quantity in the affected tank using the measuring stick procedure; both fuel flow indicators must be operating properly; and the fuel used or fuel remaining functions of the totaliser must be operating properly. This means the flight crew must perform a dipstick check before every flight on the affected tank, adding to pre-flight procedures. The operator also has a duty to keep records of compliance, although this is implicit in all ADs - the directive does not explicitly state record-keeping requirements, but under CASR Part 39, operators are typically required to maintain a log of AD compliance. As for rights, the operator has the right to use any of the listed AMMs. They have the right to defer corrective action for a single-tank discrepancy for up to 10 days, but only if they can meet the conditions. This right is limited and conditional. The operator also has the right to correct the FQIS at any time, even before the 10 day period expires. The directive does not specify a right of appeal or alternative means of compliance, but such rights would be found in the broader regulatory framework (e.g., CASR Part 39 allows for alternative means of compliance with CASA approval). The operator has no right to ignore the directive or to use methods other than those prescribed. The directive also creates a right for CASA to take enforcement action if the duties are not met. For maintenance organisations, the duties flow through contracts, but the legal duty rests with the operator as the registered holder of the aircraft. The amendment correcting the typographical error does not change the substance of the duties but clarifies which compliance statements correspond to which requirements. This is important because ambiguous numbering could lead to incorrect interpretation and inadvertent non-compliance.

The directive itself does not prescribe specific penalties. However, as an Airworthiness Directive issued under the Civil Aviation Safety Regulations 1998 (CASR), non-compliance is a serious matter. Under the Civil Aviation Act 1988, operating an aircraft that does not comply with an applicable AD is an offence. The Civil Aviation Safety Regulations (specifically Part 39) make it a requirement that no person may operate an aircraft in Australian airspace unless every applicable AD has been complied with. Breach of this requirement can attract penalties including criminal prosecution, civil penalties, and administrative actions. Criminal penalties under the Civil Aviation Act can include fines of up to several hundred thousand dollars and imprisonment for individuals, with higher penalties for corporations. Civil penalties may also apply under Part 4 of the Act. Administratively, CASA can issue infringement notices (on-the-spot fines) for less serious breaches, usually ranging from $1,000 to $12,000 for individuals and up to $60,000 for corporations. More significantly, CASA can suspend or cancel the airworthiness certificate of the aircraft, effectively grounding it until compliance is demonstrated. For operators who repeatedly fail to comply, CASA may suspend or revoke the operator’s Air Operator’s Certificate (AOC), which would prevent them from conducting any commercial air transport operations. The enforcement approach depends on the nature of the non-compliance. A one-off, inadvertent failure to perform the functional check within the required interval might result in a caution or an infringement notice, especially if no unsafe condition resulted. Persistent or deliberate non-compliance, or non-compliance that leads to an incident, would likely lead to stronger enforcement action. The directive’s background mentions the risk of fuel starvation and engine shutdown, so CASA would likely treat non-compliance seriously. Additionally, since this AD is based on an ANAC directive, failure to comply could affect international recognition of the aircraft’s airworthiness status, potentially preventing the aircraft from operating in other countries’ airspace. For the maintenance organisation performing the work, contractual liability may arise if their error leads to operator non-compliance. However, the legal duty primarily rests with the operator as the person responsible for the aircraft. The enforcement provisions are not detailed in the source, but they are well established in aviation law. The directive itself does not create new penalties; it relies on the existing enforcement framework. The amendment’s correction of a typographical error reduces the risk of incorrect interpretation that could lead to inadvertent non-compliance, thus reducing enforcement risk for operators who might otherwise misread the original numbering.

This directive interacts with several layers of regulation. First, it is issued under the Civil Aviation Safety Regulations 1998 (CASR), specifically Part 39 which deals with airworthiness directives. Part 39 gives CASA the power to issue ADs to address unsafe conditions, and it requires compliance by all affected parties. The directive thus has the force of law. It is a mandatory regulatory instrument, not merely an advisory bulletin. Second, the directive references the original ANAC AD 2009-07-04 from Brazil. This means that Australian operators of EMB-120 aircraft must comply with both the local CASA AD and any foreign requirements that may apply if the aircraft operates internationally. However, for aircraft registered in Australia, the CASA AD is the governing instrument, and compliance with the ANAC AD alone may not suffice if the CASA AD imposes additional or different requirements. In this case, they appear aligned. Third, the directive interacts with the maintenance regulations under CASR Part 42 (Continuing Airworthiness) and Part 145 (Maintenance Organisations). The maintenance manuals referenced in the directive are approved under the type certificate and must be followed. The directive also interacts with the operational regulations under CASR Part 121 (Aeroplane Air Transport Operations) and Part 135 (Small Aeroplane Air Transport Operations), depending on the operator’s scope. For example, the requirement to perform dipstick checks after each refuelling during the 10 day deferral period may affect pre-flight procedures that are already specified in the operator’s expositions. Fourth, the directive has implications for the Civil Aviation Act 1988, which creates the offence of operating a non-compliant aircraft. If an operator fails to comply with this AD, they could be prosecuted under section 20A of the Act for operating an aircraft without a valid airworthiness certificate (since non-compliance with an AD makes the certificate invalid). Fifth, there may be interactions with the Navigation Act 2012 if the aircraft is used in international air navigation, though that is less likely for these regional aircraft. Sixth, the directive does not appear to affect state or territory laws, but it could interact with workplace health and safety laws if maintenance personnel are injured while performing the prescribed tasks. The directive itself does not address this, but the operator must ensure a safe work environment. Finally, the directive may have contractual interactions. Many lease agreements and financing documents require compliance with all ADs, so non-compliance could constitute a default. Insurance policies may also exclude coverage if the aircraft is operated in breach of an AD. The amendment correcting a typographical error reduces the risk of legal disputes about the meaning of the original compliance statements. Overall, the directive fits within a web of aviation safety regulation and commercial law.

AD/EMB-120/49 Amdt 1 is an amendment to the original AD/EMB-120/49. The source document itself is the amendment, and it states that the original issue became effective on 27 August 2009. This amendment is dated 12 August 2009 and becomes effective on the same date - 27 August 2009. The purpose of the amendment is limited: it corrects a typographical error in the numbering of the Compliance statements. The original directive presumably had a numbering error that could cause confusion. The amendment does not change the requirements or the compliance times; it only fixes the numbering in the compliance section. The amendment is signed by James Coyne, a Delegate of CASA, on 12 August 2009. The document is identified as DM 10/2009, indicating it is part of CASA’s formal directive management system. The aviation regulatory environment often sees amendments for errors like this, as precision is critical. The background note explicitly states: This amendment corrects a typographical error in the numbering of the Compliance statements. This suggests that the original compliance statements may have misnumbered paragraphs, potentially leading operators to apply the wrong compliance time to a requirement. For example, Requirement 3 might have been mis-numbered as 2 or vice versa. The amendment ensures that each requirement has the correct compliance statement associated with it. There is no indication of any other amendments before or after this one, based on the source. However, as an AD can be superseded, it is possible that later amendments exist but are not referenced here. The effective date of 27 August 2009 is the same for both the original and the amendment, indicating that the amendment was issued contemporaneously to correct the error before the effective date. This is a common practice: regulators discover an error during pre-publication review and issue an amendment immediately. For operators tracking compliance history, this amendment is a ministerial correction that should be read as part of the original directive. The original issue and the amendment are both dated August 2009, so there is no gap where the erroneous version was in force. This minimises confusion and ensures that from the moment the directive took effect, the correct compliance statements applied. The amendment history is thus straightforward: original issue (27 August 2009) and this amendment (also effective 27 August 2009) correcting a typo. No further history is provided in the source.

The source document does not reference any litigation history. There is no mention of any court cases, appeals, or legal challenges related to AD/EMB-120/49 or the underlying ANAC AD 2009-07-04. This is typical for individual airworthiness directives; they are technical safety instruments that are rarely litigated directly. Challenges to ADs are possible in theory - for example, an operator might argue that the directive is not justified by the safety evidence or that it imposes an unreasonable burden - but such challenges are uncommon in Australia. The Civil Aviation Act 1988 provides for judicial review of CASA decisions under the Administrative Decisions (Judicial Review) Act 1977, but that would require an operator to have standing and to demonstrate that CASA exceeded its powers or acted unreasonably. No such challenges are recorded in the source. The lack of litigation history does not necessarily mean no disputes have arisen; it may mean that any disputes were resolved administratively through CASA’s internal processes or through alternative means of compliance requests. Given that this directive is based on a Brazilian ANAC directive, operators might have engaged with CASA or ANAC to request extensions or modifications, but that would not constitute litigation. The amendment itself - correcting a typo - suggests that CASA realised an error and fixed it without adversarial proceedings. The background states that ANAC found probe failures causing erroneous indications, which is a technical finding that would be hard to dispute. So litigation history is blank. In a deep dive, it is appropriate to note this absence and explain why litigation is rare for such instruments.

Several potential traps exist in this directive for the unwary operator or maintainer. First, the 60 kg threshold applies to both the master indicator and the repeater indicator. It says the difference of the indicated fuel quantity is 60 kg or less. This means the difference between the dipstick reading and the master indicator, and separately between the dipstick reading and the repeater indicator, must each be 60 kg or less. If one indicator is out of tolerance but the other is within, does the operator need to correct only the faulty one? The directive treats indicated fuel quantity collectively but then requires correction based on the difference on each tank. The phrasing could be interpreted to mean that if either indicator reading differs from the dipstick by more than 60 kg, action is required. Second, for Requirement 2.b. (single tank out of tolerance, deferral allowed), the conditions require that after each refuelling, the real fuel quantity must be determined using the measuring stick procedure per Requirement 1. This means the operator must constantly redo the dipstick check before every flight after refuelling. This may be operationally burdensome and easy to overlook, especially if refuelling occurs at multiple stops. Third, the directive requires both fuel flow indicators to be operating properly, and the fuel used or fuel remaining functions of the totaliser to be operating properly. If any of these functions are inoperative, the deferral is invalid and the FQIS must be corrected before the next flight. Operators might not immediately connect the inoperative totaliser to their ability to defer the FQIS correction. Fourth, the terms master indicator and repeater indicator are not defined in the directive. In different EMB-120 configurations, these may be located in different places. The AMM task reference helps, but if the manual is not easily accessible, the operator must know which indicators correspond. Fifth, the amendment corrects a typo, but if the operator is using the original issue without realising it has been amended, they might follow the wrong compliance statements. Sixth, the compliance time for the initial inspection: it must be done within the next 600 hours TIS or 180 days after the effective date of the original issue of this Directive. The original issue effective date is 27 August 2009. If an operator starts using a new-to-fleet aircraft after that date, the calculation might be from a different point. Note 2 says that if the initial inspection was accomplished under the original issue, the repetitive intervals start from that inspection date. But if no initial inspection was done, the operator must start from the effective date. Seventh, for aircraft that are not in service for long periods, the 180 day calendar limit may catch operators who do not track it carefully. Eighth, the requirement to perform the check with at least 400 kg in each tank means the operator cannot do the check on a nearly empty aircraft; they must plan for fuelling. Ninth, the directive does not specify who pays for the corrective action, but that is a commercial issue, not a regulatory one. Nonetheless, disputes over cost allocation could arise. Finally, the directive is signed by a delegate of CASA, but the authority to issue it is not contested. These gotchas highlight the importance of thorough compliance tracking.

Compliance with AD/EMB-120/49 Amdt 1 requires a systematic approach. First, the operator must identify all EMB-120 series aircraft in their fleet (including EMB-120, EMB-120RT, EMB-120ER, EMB-120FC, and EMB-120QC) and verify whether they have complied with the original issue of this AD. If the initial functional check (Requirement 1) has not been performed since the effective date (27 August 2009), it must be scheduled immediately within 600 hours TIS or 180 days from that date, whichever comes first. The check must be performed with at least 400 kg (882 lb) of fuel in each tank. The technician must refer to the AMM task 28-42-00 from one of the manuals listed in Table 1: MM120/1459, MM120BAS/718, MM120CAL/921, MM120DLT/724, MM120TEX/880 (all revision date 30 July 2004), or the alternative OTFN 1VC97-2 (pages dated 1986/1987). The procedure involves using dripless measuring sticks to obtain the real fuel quantity. Then, the technician compares this measurement to the master indicator and repeater indicator for each tank. If each difference is 60 kg or less, no further action is needed, and the operator records compliance and sets the next interval at 600 hours TIS or 180 days. If the difference exceeds 60 kg on both tanks, the FQIS must be corrected before the next flight. This likely involves replacing or adjusting the probes, wiring, or indicators per the AMM. If the difference exceeds 60 kg on only one tank, the operator has two options: either correct the FQIS before the next flight, or defer correction for up to 10 days provided three conditions are met. Condition a: after each refuelling, the real fuel quantity in the affected tank must be determined using the same measuring stick procedure. The flight crew must implement this as an additional pre-flight step. Condition b: both fuel flow indicators must be operating properly - these must be checked as serviceable. Condition c: the fuel used or fuel remaining functions of the totaliser must be operating properly. If any condition fails at any time during the 10 day period, the FQIS must be corrected before the next flight. If the conditions are met, the operator has 10 days from the functional check to correct the indication. Requirement 3 states that if the conditions for deferral (2.b. a,b,c) are not met, the FQIS must be corrected before the next flight. The operator must document all steps, including the dipstick readings, indicator readings, the decision to defer or correct, and the date of correction. The maintenance log must show compliance with the repetitive interval. For repetitive compliance, the next functional check must be performed within 600 hours TIS or 180 days from the last check. The operator should set up a tracking system (e.g., in the maintenance computer system) to alert before the deadline. Finally, keep a copy of the directive (including this amendment) in the maintenance manual for reference. Ensure that technicians are trained on the specific AMM procedure, including the correct use of dripless measuring sticks. For international operations, verify that compliance with this CASA AD also satisfies the ANAC AD if the aircraft flies to Brazil. If any part of the compliance process is unclear, contact CASA’s airworthiness division for guidance. The key is to start the process early, track intervals diligently, and document thoroughly to avoid enforcement action.