1. NPA 2007-09 WG145.012: Single and multiple releases
Juan Anton
05 July 2007

2. Current certification system
Current Part-145 requirements for certification of aircraft maintenance:
145.A.50(a): “A certificate of release to service shall be issued by appropriately authorised certifying staff when it has been verified that …..”
145.A.50(b): “A certificate of release to service shall be issued before flight at the completion of any maintenance”.
05 July 2007
WG : Single and multiple releases

3. Current certification system
Currently, two different certification systems coexist in Europe:
Single release:
Maintenance tasks are signed-off by authorised personnel.
A final CRS is issued before flight by certifying staff.
Multiple release:
Each organisation may issue one or several CRS, each one of them covering one or several tasks.
05 July 2007
WG : Single and multiple releases

4. Current certification system
Single release system:
Advantages:
All actions are certified by a single person who is also responsible for coordination.
The pilot knows that when the CRS is issued it means that all maintenance has been completed and the aircraft is ready for service.
05 July 2007
WG : Single and multiple releases

5. Current certification system
Single release system:
Shortcomings:
It is not clear how this system can address the case where several organisations are involved:
Which organisation is responsible for the final CRS?
The person issuing the final CRS must have capability to sign for all the work.
The person issuing the final CRS is responsible for the work performed by all organisations.
Usually, in this case, the system becomes a Multiple Release System where each organisation issues a CRS for its own work.
05 July 2007
WG : Single and multiple releases

6. Current certification system
Multiple release system:
Advantages:
From a practical point of view, the system is more flexible, allowing each individual to be responsible for his own work.
It allows, in Line Maintenance, the use of several category A certifying staff, without intervention of B1 or B2 license holders.
05 July 2007
WG : Single and multiple releases

7. Current certification system
Multiple release system:
Shortcomings:
When several organisations or individuals are involved in a maintenance event, there could be lack of coordination (work performed in 2 engines requiring in some cases a flight test, functional tests that can not be performed until another organisation finishes its work….)
It is more difficult to ensure compliance with all the work ordered by the operator.
It is more difficult for the pilot to know when all maintenance has been completed and when the aircraft is ready for service.
05 July 2007
WG : Single and multiple releases

8. Current certification system
Issues related to the coexistence of both systems
In addition to lack of standardisation, there may be safety issues:
Example:
An operator performing maintenance in different countries may receive release documentation issued under both systems. This may lead an operator used to receive a final CRS to think that the aircraft is ready for service when receiving a CRS under a multiple release system, which may not be true.
05 July 2007
WG : Single and multiple releases

9. WG 145.012: Single and multiple releases
Task
A working group was created, with members from Industry, NAA´s and EASA.
12 meetings (2 full days each) were held between July 2005 and April 2007
Very different points of view.
Rulemaking action would affect only Part-145 organisations. Subpart-F environment requires a much lower level of coordination (more simple maintenance requirements & fewer contracted organisations)
Rulemaking action affects aircraft maintenance (not component maintenance).
05 July 2007
WG : Single and multiple releases

10. WG 145.012: Single and multiple releases
Possible options
Option 1: Do nothing (coexistence of 2 systems)
Option 2: Single CRS with coordination (currently exists):
Base Maintenance: tasks are signed-off. Each organisation issues a CRS and there is a final CRS.
Line Maintenance: tasks are signed-off and there is a final CRS.
No formal concept of PMO (Primary Maintenance Organisation) responsible for coordination and issuance of final CRS.
The final CRS certifies that the aircraft is ready for service but the other CRS don´t.
Option 3: Multiple CRS (currently exists)
One or several CRS issued by each organisation, both in line and base maintenance. Each CRS covers one or several tasks.
05 July 2007
WG : Single and multiple releases

11. WG 145.012: Single and multiple releases
Possible options
Options 4a & 4b: Multiple maintenance certification and final CRS
One or several MRC (Maintenance Release Certificate) issued by each organisation. Final CRS issued by PMO.
Different options in line maintenance depending on whether the organisation issuing the final CRS is the one that performed the maintenance or not. May not be necessary the issuance of the MRC.
Option 5:
One MRC issued by each organisation both in line and base maintenance. Final CRS issued by PMO.
05 July 2007
WG : Single and multiple releases

12. WG 145.012: Single and multiple releases
Possible options
A consensus could not be reached as to what option should be selected, and an Option 6 was proposed (combination of Options 2, 4a, 4b and 5). This Option 6 was agreed by the majority of the group.
Option 6 was based on the concepts of Maintenance Release Certificates (MRC) and final CRS issued by a Primary Maintenance Organisation (PMO) nominated by the operator.
05 July 2007
WG : Single and multiple releases

13. WG 145.012: Single and multiple releases
Option 6: Key aspects
Initially, Option 6 consisted of:
Base Maintenance: An MRC issued by each organisation and final CRS issued by PMO. Both MRC and CRS signed by certifying staff.
Line Maintenance: At least 1 MRC per organisation for each license category and final CRS issued by PMO. Both MRC and CRS signed by certifying staff.
After further development to cover cases where there is additional line maintenance performed after base maintenance, Option 6 resulted in the following concept, as proposed by the NPA (including a BMRC)
05 July 2007
WG : Single and multiple releases

14. Primary Maintenance Organisation (PMO)
The Operator nominates a PMO (M.A.708(b)7 and AMC):
Base Maintenance: the organisation performing the majority of maintenance (linked to number of tasks or man-hours or number of affected systems). Should be the organisation with the broadest view and control of the base maintenance event.
Line Maintenance: the organisation that will be responsible for issuing the CRS.
Nomination may be included in the maintenance contract or in the work order. It can be a long term agreement or single event agreement.
Between two flights the operator may nominate one PMO for base + line or one for base and another for line. It must be clear. Only 1 PMO at each particular moment.
If the PMO is changed, the operator should provide the new PMO all the necessary information regarding the previous maintenance.
05 July 2007
WG : Single and multiple releases

15. Certification of aircraft maintenance
The certification of maintenance shall include (145.A.50(a)):
Maintenance Release Certificates (MRC), and
Base Maintenance Release Certificate (BMRC), if applicable, and
Certificate of Release to Service (CRS).
A key aspect is that a single CRS must be issued before flight, ensuring to the pilot that the aircraft is ready for service (always in relation to the maintenance ordered by the operator, who retains the final responsibility for the airworthiness of the aircraft and for contracting the required maintenance)
05 July 2007
WG : Single and multiple releases

16. Maintenance Release Certificates (MRC) (responsibilities)
The MRC is issued when: (145.A.50(b)(1) and AMC)
The maintenance ordered to that organisation has been properly carried out in accordance with Part-145, and
The maintenance performed by contracted Part-145 organisations has been coordinated and the MRCs have been received, and
Outstanding defects and non-compliances have been properly recorded and notified to the PMO.
05 July 2007
WG : Single and multiple releases

17. Maintenance Release Certificates (MRC) (responsibilities)
Other aspects of the MRC:
The MRC does not imply that the aircraft is ready for service.
Allows the certification of maintenance even if the aircraft has been left in a non-approved configuration (engine removed, crack found after NDT, etc).
Not responsible for the work performed by contracted Part-145 organisations nor for the qualification of their personnel (they issue their own MRC).
05 July 2007
WG : Single and multiple releases

18. Maintenance Release Certificates (MRC) (who issues the MRC)
The MRC is issued by: (145.A.50(b)(1))
For Base Maintenance: An MRC issued by each Part-145 organisation, using:
Category C certifying staff.
Organisations other than PMO may use:
B1/B2/A certifying staff if tasks performed under line maintenance approval.
NDT certifying staff for D1 rated organisations.
For Line Maintenance: At least one MRC issued by each Part-145 organisation, using:
B1/B2/A certifying staff.
05 July 2007
WG : Single and multiple releases

19. WG 145.012: Single and multiple releases
Maintenance Release Certificates (MRC) (comparison with current system)
For Base Maintenance:
The MRC is similar to the current CRS issued by each organisation in Base Maintenance.
For Line Maintenance:
The MRC is similar to the current CRS issued in:
multiple release systems;
single release systems prior to the issuance of a final CRS.
It is also a flexible system because each organisation can choose whether it issues one MRC to cover all tasks or issues an MRC for each single task.
05 July 2007
WG : Single and multiple releases

20. WG 145.012: Single and multiple releases
Maintenance Release Certificates (MRC) (comparison with current system)
Similarly to the current CRS, each organisation issuing an MRC takes full responsibility for the work performed.
The MRC allows the certification of maintenance also in the following cases:
The organisation has received a Work Order that leaves the aircraft in a non-approved configuration (removal of engine, NDT inspection which detects a crack out of limits….)
The organisation leaves uncompleted work to be finished by another organisation.
In both cases non-conformances need to be recorded and notified to the PMO.
05 July 2007
WG : Single and multiple releases

21. Base Maintenance Release Certificate (BMRC) (responsibilities)
The BMRC is issued by the PMO when: (ref. 145.A.50(b)(2) and AMC)
All required MRCs have been issued, and
All the maintenance ordered by the operator in a Base Maintenance event has been completed or properly deferred, and
All activities were properly coordinated, and
There are no non-compliances which are known that seriously hazard the flight safety.
05 July 2007
WG : Single and multiple releases

22. Base Maintenance Release Certificate (BMRC) (responsibilities)
Other aspects of the BMRC:
The BMRC does not imply that the aircraft is ready for service.
Proper coordination between organisations must be ensured.
The PMO is not responsible for the work performed by the other Part-145 organisations nor for the qualification of their personnel (they issue their own MRC).
05 July 2007
WG : Single and multiple releases

23. Base Maintenance Release Certificate (BMRC) (who issues the BMRC)
The BMRC is issued by: (ref.145.A.50(b)(2))
Category C certifying staff of the PMO.
05 July 2007
WG : Single and multiple releases

24. WG 145.012: Single and multiple releases
Base Maintenance Release Certificate (BMRC) (comparison with current system)
Currently, in a pure single release system, a final CRS is issued after Base Maintenance covering the CRS issued by each organisation. However, it is not clear what responsibility assumes the organisation who issues the final CRS in relation to the work performed by the other organisations.
In the proposed system the BMRC is issued after Base Maintenance, without assuming the responsibility of the work already certified by each MRC.
05 July 2007
WG : Single and multiple releases

25. WG 145.012: Single and multiple releases
Base Maintenance Release Certificate (BMRC) (comparison with current system)
Question: If the BMRC is equivalent to the current final CRS after Base Maintenance, why we don´t call it CRS?
The reason is that there are cases where, after the Base Maintenance is finished, there is a need to perform additional Line Maintenance, even changing organisations.
Nevertheless, the BMRC certifies that all the work ordered in the Base Maintenance event has been performed or properly deferred.
05 July 2007
WG : Single and multiple releases

26. Certificate of Release to Service (CRS) (responsibilities)
The CRS is issued by the PMO when: (145.A.50(b)(3) and AMC):
All required MRCs for Line Maintenance and the BMRC for Base Maintenance, as applicable, have been issued, and
All the maintenance ordered by the operator has been completed or properly deferred, and
All activities were properly coordinated, and
There are no non-compliances which are known that seriously hazard the flight safety.
05 July 2007
WG : Single and multiple releases

27. Certificate of Release to Service (CRS) (responsibilities)
Other aspects of the CRS:
If the operator nominates a PMO responsible for issuing the CRS different from the one that issued the BMRC, the operator is responsible for informing the new PMO about the maintenance already performed and any possible conflicts with the new maintenance to be performed.
The PMO is not responsible for the work certified by the MRC´s and BMRC issued by other organisations nor for the qualification of their personnel.
05 July 2007
WG : Single and multiple releases

28. Certificate of Release to Service (CRS) (who issues the CRS)
The CRS is issued by the PMO using: (ref. 145.A.50(b)(3))
Category B1 or B2 certifying staff (any of them), or
Category C certifying staff when no line maintenance has been performed after the issuance of the BMRC.
Category A certifying staff when no Base Maintenance has been performed and all the Line Maintenance has been performed by this person.
05 July 2007
WG : Single and multiple releases

29. WG 145.012: Single and multiple releases
Conclusions
Appropriate coordination is ensured by the PMO, both in Line & Base maintenance.
Each organisation issuing an MRC takes full responsibility for the work performed and the qualification of its personnel.
The BMRC certifies that all the work ordered in a Base maintenance event has been completed or properly deferred.
During a Base Maintenance event it is possible to include also Line Maintenance Tasks, and cover all of them within the BMRC.
05 July 2007
WG : Single and multiple releases

30. WG 145.012: Single and multiple releases
Conclusions
One single certificate can accommodate MRC, BMRC and CRS.
Different types of Technical Log can be developed to fit current existing systems:
Each maintenance action is issued an MRC, or
Each maintenance action is signed-off and one or several MRCs are issued combining several tasks.
The system is very flexible and does not require to assume responsibility for the work performed by other organisations.
The system very clearly delimits the responsibility of each organisation.
05 July 2007
WG : Single and multiple releases