Mind the OEBs

An Operations Engineering Bulletin (OEB) is a temporary procedure published for flight crews, which must be applied in specific conditions to ensure the safe and efficient operation of the aircraft. An OEB is applicable until a permanent corrective solution is installed on the aircraft.

There are two types of OEB:

• Red OEB: Safety related OEB where non-compliance may have a significant impact on the safe operations of the aircraft
• White OEB: Non-compliance may have a significant impact on the efficient operations of the aircraft (e.g. diversions or delays)

OEBs can be published and made applicable to any Airbus aircraft with the exception of the A220 family.

OEBs can be found in the FCOM of A350 and A380 aircraft. OEBs are currently published in both the FCOM and the QRH for the A320 family and A330/A340 aircraft. From the end of 2020, OEBs for these aircraft will only be available in the QRH. A300/A310 aircraft OEBs can be found in both the FCOM and QRH.

When preparing for a flight, the flight crew must know the answers to the following questions:

• What are the OEBs applicable to this aircraft?
• What are the specific entry conditions for applying these OEBs?
• What are the cockpit effects and system effects of the OEBs when applied on the aircraft?

It is essential that flight crews know precisely which OEBs are applicable to their aircraft before each flight.

Several events with the potential of negative outcomes have occurred when flight crews inappropriately applied an OEB that was not applicable for the aircraft they were flying. This risk is higher for Operators with diverse fleets of aircraft models and of different ages. Some flight crews may fly several aircraft over a short period of time with different OEBs that are applicable.

Review the OEBs before each flight

Airbus Standard Operating Procedures (SOPs) request flight crews to review all applicable OEBs during the preliminary cockpit preparation phase of each flight to mitigate this risk, even when in transit.

OEBs only apply in very specific conditions. These conditions can be either an ECAM alert or another defined event.

Flight crews must be precisely able to recognize the defined conditions that will require the application of an OEB. Any ECAM entry conditions are defined in the OEB and are also described in the LEOEB. If an OEB does not have an ECAM entry condition, the conditions of a defined event that requires application of an OEB is provided in the OEB description.

Inappropriate application of an OEB can potentially impair safety

Events have occurred as a result of inappropriate application of an OEB following the misinterpretation of the aircraft parameters. Refer to the “Overspeed event with crew take-over and OEB49 application” Safety first article (June 2019) that describes an incident in which the flight crew improperly applied an OEB whereas the entry conditions were not met.

Flight crews must fully understand the OEB procedure and the effects of its application. A well-prepared flight crew should already know the content of the applicable OEBs before entering the cockpit or take the time to review them during the preliminary cockpit preparation phase.

The explanation of each OEB is attached to the procedure (in the FCOM today for all Airbus aircraft, but from the end of 2020 only in the QRH for A320 family and A330/A340 aircraft). The explanation provides a concise description of the context and the reason for the OEB. Flight crews must refer to these explanations, and any other supporting materials provided by Airbus, or their flight operations department, to be confident in the correct application of the OEB procedures.

Airbus may decide to publish an OEB when a situation is identified that could pose a potential risk to the safe operations of the aircraft and there is no existing procedure or technical solution to manage this risk. A published OEB is applicable until a permanent corrective solution is installed on the aircraft.

Airbus will closely coordinate with Authorities throughout the OEB decision-making process and publication of the relevant documentation. As in the case of a red OEB, Authorities will issue an Airworthiness Directive (AD) and Airbus will issue the associated update of the Airplane Flight Manual (AFM).

When the decision is made to issue an OEB, the goal is to make it available to Operators as soon as possible.

Notice of an OEB sent to Operators

Airbus Flight Operations will issue a Flight Operations Transmission (FOT) explaining the rationale for the OEB, the content of the OEB itself as an advance copy, and the AFM Temporary Revision text if required (for red OEBs).

Operational Documentation Update

An update to the FCOM and QRH will incorporate the new applicable OEBs published since the last revision. The AFM will also be updated if required (for red OEBs).

Continuous Support to Operators

Airbus provides Operators with supporting materials via the AirbusWorld portal and web conferences to well understand and manage the new OEB, which is key to safe application of the OEB.

The objective for Operators is to deploy any new OEB as soon as it is available. It is best practice that all Operators have a defined process, which will ensure rapid implementation of the OEB and its content is fully understood by flight crews. This will contribute to ensuring that the flight crew is aware of any applicable OEBs and will reduce the risk of inappropriate application of an OEB.

Operators can use the OEB advance copy sent by Airbus with the FOT to make the OEB available in the cockpit for flight crews as soon as possible.

When the decision is made to issue an OEB, Airbus takes the necessary actions at the same time to quickly find a solution to cancel this OEB. We must keep in mind that an OEB is only temporary pending the availability of a permanent solution.

As soon as a solution is found to cancel the OEB, Airbus will publish one or several Service Bulletins (SBs) with instructions to apply the modifications on the aircraft. A Retrofit Information Letter (RIL) is usually sent to Operators to inform them of the availability of the SB.

As soon as the fix is available to cancel an OEB, it is important to implement it in a timely manner on affected aircraft. It is always better from a safety and operational perspective to operate aircraft with the minimum possible number of OEBs.

Operational Documentation Update When SBs are Implemented

To prevent inappropriate application of an OEB, it is crucial that the aircraft configuration (SB installation) and the onboard operational documentation (list of applicable OEBs) are aligned. This requires close coordination between Maintenance Engineering and Flight Operations to confirm when modifications are implemented on the aircraft which will cancel an OEB. This is to avoid the risk of any significant impact to the safety of a flight if a flight crew were to attempt to apply an OEB procedure that is no longer applicable to their aircraft.

Report of Service Bulletin Installation to Airbus

Service Bulletin reporting is required to ensure that Airbus and Operators share the same view of the retrofit status for the fleet and to trigger the update of all operational documentation. Operators can also request operational documentation to be updated in advance of the standard revision cycle.

Reporting is done via the Service Bulletin Reporting Online tool. (Ref. ISI 00.00.00135 available on the AirbusWorld portal)

• Service Bulletin reporting should be done aircraft per aircraft and not only reported at the completion of the retrofit cycle for the entire fleet.
• Operators can manually remove the OEBs from their current versions of operational documentation pending the availability of the updated version.

Limiting the number of OEBs applicable to an aircraft improves safety because it enables the Operator to resume standard aircraft operations. Operators should therefore install the OEB cancellation modifications as soon as possible after they are informed they are available.

Airbus Support for OEB Reduction Strategies

Operators should define and secure a retrofit strategy for their fleets with appropriate priority management, for example, any corrective actions mandated by an Airworthiness Directive or red OEBs.

Operators can ask Airbus Customer Support to provide them with a full status of the available solutions for their current list of effective OEBs, the retrofit priorities, instructions, and recommendations.

Operators can also access information on the AirbusWorld portal with the updates of the Technical Follow-Up (TFU) associated with an OEB and the latest “Digest of Available Safety Enhancements” brochure published annually. This brochure includes information on safety enhancements, which were developed in response to the in-service experience of the Airbus fleet. Many of these enhancements will also cancel an associated OEB.